BIOLOGICAL CLASSIFICATION

GUMROAD eBook link:-

BY SHAILENDRA KUMAR VERMA

1.	CHALLENGING SYLLOGISM
	https://skverma29.gumroad.com/l/ktxvzi
2.	STRAIT OF HORMUZ: STRATEGIC & ECONOMIC ROLE
	https://skverma29.gumroad.com/l/upobrv
4.	STATIC GENERAL KNOWLEDGE
	https://skverma29.gumroad.com/l/kzmca
5.	SSC ENGLISH PREVIOUS YEAR QUESTIONS MCQ
	https://skverma29.gumroad.com/l/vtotyp
6.	SSC REASONING PREVIOUS YEAR QUESTIONS MCQ
	https://skverma29.gumroad.com/l/fsyvp
7.	SSC MATH PREVIOUS YEAR QUESTIONS (MCQ): TIER I
	https://skverma29.gumroad.com/l/nesioq
8.	BANKING KNOWLEDGE QUESTIONS AND ANSWERS MCQ
	https://skverma29.gumroad.com/l/sgbbul
9.	BIHAR ANM, GNM & PHARMACIST EXAM: PAST MCQ QUESTIONS & ANSWERS –
	https://skverma29.gumroad.com/l/yotjat
10.	ARAVALLI MOUNTAIN RANGE: THE ANCIENT SPINE OF INDIA
	https://skverma29.gumroad.com/l/khpakf
11.	मौर्य काल (322 ईसा पूर्व – 185 ईसा पूर्व): पीएसयू परीक्षा हेतु प्रश्नोत्तर सहित विस्तृत अध्ययन
	https://skverma29.gumroad.com/l/kgmrw
12.	VOLCANOES AND EARTHQUAKES: A COMPLETE GUIDE
	https://share.google/gMZLAnx4hcCV82NTI
13.	TERMINOLOGY: RAILWAY, COMPUTER, SHARE MARKET, BIOLOGY, BADMINTON, CRICKET, FOOTBALL, KABBADI AND HOCKEY
	https://share.google/fvdFN53HtyXlqTCgd
14.	भारतीय संसद का सत्र: प्रक्रिया, नियमऔर एस ओ पी; पी एस यू परीक्षा के लिए संपूर्ण मार्ग दर्शिका
	https://share.google/1HFwXZA3qUiKyrI1l
15.	REITs AND InvITs IN INDIA: COMPLETE GUIDE (SCOPE, RISKS & FUTURE)
	https://share.google/EChDc9heQmPPeyhoi
16.	GK SSC TIER I PREVIOUS YEAR MCQ
	https://share.google/5pLzqYKQtg822wk3Y
17.	PETROLEUM REFINERY PROCESS: WITH 200 MCQ
	https://skverma29.gumroad.com/l/jgydi
18.	SET THEORY:  A COMPLETE GUIDE WITH 400 MCQ
	https://skverma29.gumroad.com/l/zkhqzm
19.	WORLD’S SMALLEST, LONGEST, THINNEST, THICKEST AND TALLEST
	https://skverma29.gumroad.com/l/kzaenh
20.	HIGH TIDE AND LOW TIDE: A COMPLETE GUIDE https://skverma29.gumroad.com/l/virke
21.	1000 HISTORY QESTIONS & ANSWERS FOR PSU
	https://skverma29.gumroad.com/l/fjapus
22.	नालंदा विश्वविद्यालय : सम्पूर्ण अध्ययन
	https://skverma29.gumroad.com/l/pmjab?wanted=true
23.	भगवान  शिव के 12 ज्योतिर्लिंग: इतिहास, महत्व और दर्शन क्रम
	https://skverma29.gumroad.com/l/wdkgo
24	NISM-SERIES-V-A MUTUAL FUND DISTRIBUTOR: COMPLETE STUDY GUIDE  & EXAM PREPARATION
	https://skverma29.gumroad.com/l/qgcviu
25.	WORKSHOP TECHNOLOGY & MANUFACTURING PROCESSES COMPLETE EXAM GUIDE
	https://skverma29.gumroad.com/l/xvqxnp

AMAZON eBook link:-

BY SHAILENDRA KUMAR VERMA

1.	SSC MATH PREVIOUS YEAR MCQ: SSC MATH
	https://amzn.in/d/097Ocsnl
2.	SSC REASONING PREVIOUS YEAR MCQ: SSC REASONING
	https://amzn.in/d/00EHQGE8
3.	SSC ENGLISH PREVIOUS YEAR MCQ: SSC ENGLISH
	https://amzn.in/d/0f8sxJoy
4.	STATIC GENERAL KNOWLEDGE : WITH 620 MCQs
	https://amzn.in/d/09xNEWmt

PLAYSTORE eBook link:-

BY SHAILENDRA KUMAR VERMA

1.	SSC MATH PREVIOUS YEAR MCQ
	https://share.google/KzWbvkFuNk51PEpiu
2.	SSC REASONING PREVIOUS YEAR MCQ
	https://play.google.com/books/publish/a/12574378860292240754#book/GGKEY:EUPQZ9ZUAFR/review
3.	STATIC GENERAL KNOWLEDGE
	https://play.google.com/books/publish/a/12574378860292240754#book/GGKEY:CQDT2G4CCQP/review
4.	CHALLENGING SYLLOGISM
	https://share.google/w9xLMwyiJdNVnpHxI
5.	STRAIT OF HORMUZ: STRATEGIC & ECONOMIC ROLE
	https://share.google/V10H7UKeTkstLIMmc
6.	BIHAR TEACHER ELIGIBILITY TEST (BIHAR TET) : COMPLETE GUIDE
	https://share.google/AcCXPFa69dAWyYaZZ
7.	SSC ENGLISH PREVIOUS YEAR MCQ
	https://share.google/pr7b0YhDoDwttaq2s
8.	BANKING KNOWLEDGE QUESTIONS AND ANSWERS MCQ
	https://share.google/yqYOabKhNppcz89hl
9.	BIHAR ANM, GNM & PHARMACIST EXAM: PAST MCQ QUESTIONS & ANSWERS –
	https://share.google/NFhtU1JoBfxPS4wa3
10.	ARAVALLI MOUNTAIN RANGE: THE ANCIENT SPINE OF INDIA
	https://share.google/Yo4RYnaZrbRu9qwzj
11.	GK SSC TIER I PREVIOUS YEAR MCQ
	https://share.google/sBdCcsEeebM44QZ0X
12.	REITs AND InvITs IN INDIA: COMPLETE GUIDE (SCOPE, RISKS & FUTURE)
	https://share.google/XAwUio1deUOxFe2M7
13.	भारतीय संसद का सत्र: प्रक्रिया, नियमऔर एस ओ पी ; पी एस यू परीक्षा के लिए संपूर्ण मार्ग दर्शिका
	https://share.google/6XVrfQ2PcuWmqvKol
14.	मौर्य काल (322 ईसा पूर्व – 185 ईसा पूर्व): पीएसयू परीक्षा हेतु प्रश्नोत्तर सहित विस्तृत अध्ययन
	https://share.google/Lwu7JKHE54kxsL5e2
15.	TERMINOLOGY: RAILWAY, COMPUTER, SHARE MARKET, BIOLOGY, BADMINTON, CRICKET, FOOTBALL, KABBADI AND HOCKEY
	https://share.google/WWVO9ZFd81R9G9h69
16.	VOLCANOES AND EARTHQUAKES: A COMPLETE GUIDE
	https://share.google/aXi2evRVgmzpQguye
17.	PETROLEUM REFINERY PROCESS: WITH 200 MCQ
	https://play.google.com/books/publish/u/0/a/12574378860292240754#book/GGKEY:P34SQBHUJ7F/review
18.	SET THEORY:  A COMPLETE GUIDE WITH 400 MCQ	SET THEORY:  A COMPLETE GUIDE WITH 400 MCQ
	https://play.google.com/books/publish/u/0/a/12574378860292240754#book/GGKEY:83LKH7QHRQH/review
19.	WORLD’S SMALLEST, LONGEST, THINNEST, THICKEST AND TALLEST
	https://play.google.com/books/publish/u/0/a/12574378860292240754#book/GGKEY:9LE49HEDZJE/review
20.	HIGH TIDE AND LOW TIDE: A COMPLETE GUIDE
	https://play.google.com/books/publish/u/0/a/12574378860292240754#book/GGKEY:TKR79QBDE7R/review
21.	1000 HISTORY QESTIONS & ANSWERS FOR PSU
	https://play.google.com/books/publish/u/0/a/12574378860292240754#book/GGKEY:1SGWQKT7BDF/review
22.	नालंदा विश्वविद्यालय : सम्पूर्ण अध्ययन
	https://play.google.com/books/publish/u/0/a/12574378860292240754#book/GGKEY:RY0EDLDK7TL/review
23.	भगवान  शिव के 12 ज्योतिर्लिंग: इतिहास, महत्व और दर्शन क्रम
	https://play.google.com/books/publish/u/0/a/12574378860292240754#book/GGKEY:KNT0X6L8YCQ/review
24.	NISM-SERIES-V-A MUTUAL FUND DISTRIBUTOR: COMPLETE STUDY GUIDE  & EXAM PREPARATION
	https://play.google.com/books/publish/u/0/a/12574378860292240754#book/GGKEY:YP1PQ8RQY07/review
25.	WORKSHOP TECHNOLOGY & MANUFACTURING PROCESSES COMPLETE EXAM GUIDE
	https://play.google.com/books/publish/u/0/a/12574378860292240754#book/GGKEY:PK621P1ZHXX/review

OPEN DMAT ACCONT FROM THI LINK IN ANGEL ONE:-

Open your Trading & Investment account with Angel One for FREE*

You will get:

All trades in Rs.20

Quick SIP in Direct MF

1Lac MTF @ 0% interest

Download only using my referral link to get Free Demat Account⬇

https://angel-one.onelink.me/Wjgr/2o2au42h

_link may expire within 48hrs_

_T&C Apply_

CLICK TO APPLY:

Click the application link below: 👉 Apply Here for SBI Credit Card (Referral Code: 243zfQ0yYm3)

OPEN DMAT ACCOUNT FROM  THIS LINK:

HI THERE, I SEE YOU HAVEN’T BOUGHT THE FREEDOM PLAN ON INDIAN BANK YET. DON’T MISS OUT ON UNLIMITED TRADING AT A POCKET-FRIENDLY COST. GO BROKERAGE-FREE AND SAVE BIG WITH THE FREEDOM PLAN. USE MY REFERRAL CODE, SHAI0634 TO DOWNLOAD THE APP NOW.

https://play.google.com/store/apps/details?id=com.finwizard.fisdom

BIOLOGICAL CLASSIFICATION

DISCLAIMER :

The content provided on this webpage/article on “BIOLOGICAL CLASSIFICATION” is intended strictly for educational, informational and examination-preparation purposes only. This material is designed to help students prepare for NEET and other competitive examinations.

This webpage may contain MCQ questions, answers, previous-year questions (PYQs), exam names, examination years, explanations, practice questions and NCERT-oriented study material. The questions and answers, including their exam names and years, have been compiled or presented for educational practice and revision. Although reasonable efforts have been made to maintain accuracy, the website owner does not guarantee that every question, answer, explanation, exam year, wording or classification is completely accurate or identical to the original official examination paper.

Some questions may be memory-based, reconstructed, adapted, paraphrased or compiled from publicly available educational/reference material. Therefore, students should verify the original question, answer, examination year and official examination details from the relevant official examination authority or original source wherever required.

The content relating to Biological Classification, including Monera, Protista, Fungi, viruses, viroids, prions, lichens, mycorrhiza and related topics, is presented primarily from an NCERT/NEET preparation perspective. Scientific classification and terminology may change with advances in scientific knowledge; therefore, the latest NCERT textbook and authoritative scientific sources should be consulted where applicable.

The website owner makes no representation or guarantee regarding the accuracy, completeness or current validity of any MCQ, answer, explanation, examination year or PYQ information provided on this webpage.

The website owner shall not be responsible or liable for any error, omission, incorrect answer, incorrect examination year, discrepancy, academic loss, examination result, or any other consequence arising from the use of these MCQs, answers, PYQs or study materials. Students are advised to verify important information with the latest NCERT textbook and official examination sources before relying upon it for examination purposes.

This website and its content are not affiliated with, endorsed by, sponsored by or officially associated with NTA, NEET, NCERT, the Government of India, or any examination authority, unless specifically stated.

For educational purposes only. Verify important questions, answers, exam years and syllabus information with official sources.

Website Owner: The website owner shall not be responsible for any discrepancy or consequence arising from the use of the information, MCQs, answers, PYQs or examination-year details provided on this webpage.

PART A : COMPLETE THEORY

2.1 Introduction

The living world contains an enormous variety of organisms. They differ in their structure, mode of nutrition, habitat, reproduction, cellular organisation and evolutionary relationships.

To study this enormous diversity systematically, organisms are classified into groups and sub-groups based on their similarities and differences.

The process of grouping organisms into convenient categories is called biological classification.

Classification helps us to:

Identify organisms.

Study their characteristics systematically.

Understand relationships among organisms.

Study evolutionary relationships.

Organise the enormous diversity of living organisms.

2.2 Early Systems of Classification

Two-Kingdom Classification

The earliest widely used classification system divided organisms into two kingdoms:

1. Plantae
2. Animalia

This system was associated with Carolus Linnaeus.

Major limitations

The two-kingdom system could not satisfactorily distinguish:

Prokaryotes from eukaryotes

Unicellular organisms from multicellular organisms

Autotrophs from heterotrophs

Organisms with different types of cell walls

Fungi from plants

Single-celled eukaryotic organisms

Therefore, more comprehensive classification systems were developed.

2.3 Three-Kingdom Classification

Ernst Haeckel proposed the three-kingdom classification.

The three kingdoms were:

1. Plantae
2. Animalia
3. Protista

Protista was created mainly to accommodate organisms that did not fit properly into Plantae or Animalia.

2.4 Four-Kingdom Classification

H.F. Copeland proposed a four-kingdom system.

The four kingdoms were:

1. Monera
2. Protista
3. Plantae
4. Animalia

This system separated prokaryotic organisms from eukaryotic organisms.

2.5 Five-Kingdom Classification

The most important classification system for NEET is the five-kingdom classification proposed by R.H. Whittaker in 1969.

The five kingdoms are:

1. Monera
2. Protista
3. Fungi
4. Plantae
5. Animalia

Major criteria used by Whittaker

Whittaker considered:

Cell structure

Body organisation

Mode of nutrition

Reproduction

Phylogenetic relationships

These criteria are repeatedly tested in NEET.

2.6 Five Kingdoms — Quick Comparison

Kingdom	Cell type	Organisation	Nutrition	Cell wall
Monera	Prokaryotic	Mainly unicellular	Autotrophic/heterotrophic	Usually present
Protista	Eukaryotic	Mainly unicellular	Autotrophic/heterotrophic	Variable
Fungi	Eukaryotic	Mostly multicellular	Heterotrophic, absorptive	Chitin
Plantae	Eukaryotic	Multicellular	Mainly autotrophic	Cellulose
Animalia	Eukaryotic	Multicellular	Heterotrophic, ingestive	Absent

2.7 KINGDOM MONERA

Kingdom Monera includes prokaryotic organisms.

Important examples include:

Bacteria

Cyanobacteria

Archaebacteria

Mycoplasma

General characteristics

Monerans generally:

Are prokaryotic.

Lack a true nucleus.

Lack membrane-bound organelles.

Usually possess a cell wall.

May be autotrophic or heterotrophic.

Are generally unicellular.

Their genetic material is not enclosed within a nuclear membrane.

2.8 Bacteria

Bacteria are extremely diverse organisms.

They can occur in:

Soil

Water

Air

Living organisms

Extreme environments

Based on shape, bacteria are commonly classified as:

1. Coccus

Spherical or nearly spherical.

2. Bacillus

Rod-shaped.

3. Vibrio

Comma-shaped.

4. Spirillum

Spiral-shaped.

2.9 Bacterial Cell Structure

A typical bacterial cell may contain:

Cell wall

Plasma membrane

Cytoplasm

Ribosomes

Genetic material

Flagellum

Pili

Fimbriae

Capsule/slime layer in some species

Important NEET point

Bacteria do not possess membrane-bound organelles such as:

Mitochondria

Chloroplasts

Endoplasmic reticulum

Golgi apparatus

2.10 Bacterial Cell Wall

The bacterial cell wall is generally composed of peptidoglycan.

The cell wall provides:

Shape

Mechanical support

Protection against osmotic pressure

2.11 Flagella

Some bacteria possess flagella for locomotion.

The bacterial flagellum has three main components:

1. Filament
2. Hook
3. Basal body

2.12 Pili and Fimbriae

Pili and fimbriae are hair-like structures found on some bacteria.

They can have roles in:

Attachment

Conjugation

Interaction with surfaces

NEET trap

Pili and fimbriae should not simply be considered structures mainly responsible for bacterial locomotion.

2.13 Archaebacteria

Archaebacteria are distinctive prokaryotes that can live in extreme environments.

Important groups include:

Methanogens

They produce methane and occur in anaerobic environments.

They are found in:

Marshy areas

Anaerobic environments

Rumen of cattle and other ruminants

Halophiles

They live in environments with very high salt concentration.

Thermoacidophiles

They can survive high temperatures and acidic conditions.

Important difference

Archaebacterial cell walls differ chemically from those of typical eubacteria.

This difference is an important NEET topic.

2.14 EUBACTERIA

Eubacteria are often referred to as true bacteria.

They include a very large variety of bacterial forms.

Their cell wall generally contains peptidoglycan.

2.15 Cyanobacteria

Cyanobacteria are photosynthetic prokaryotes.

They are commonly called:

Blue-green algae

However, they are bacteria, not true algae.

Examples:

Nostoc

Anabaena

They contain photosynthetic pigments and can perform photosynthesis.

Nitrogen Fixation

Some cyanobacteria can fix atmospheric nitrogen.

Specialised cells called heterocysts are associated with nitrogen fixation in certain cyanobacteria.

Examples

Nostoc

Anabaena

2.16 Mycoplasma

Mycoplasma are unusual bacteria because they lack a cell wall.

Therefore:

They are very small.

They can pass through very fine filters.

They are resistant to antibiotics that target bacterial cell walls.

They possess a plasma membrane.

Extremely important NEET fact

Mycoplasma = wall-less bacteria.

2.17 KINGDOM PROTISTA

Kingdom Protista contains mainly unicellular eukaryotic organisms.

They possess:

True nucleus

Membrane-bound organelles

Important groups include:

Chrysophytes

Dinoflagellates

Euglenoids

Slime moulds

Protozoans

2.18 Chrysophytes

Chrysophytes include:

Diatoms

Golden algae

They are mostly found in:

Freshwater

Marine environments

Diatoms have a characteristic cell wall containing silica.

Their accumulated remains can form diatomaceous earth.

Uses of diatomaceous earth

It has applications including:

Filtration

Polishing

Insulation

2.19 Dinoflagellates

Dinoflagellates are primarily marine organisms.

Many are photosynthetic.

Their cell wall may contain cellulose plates.

Some dinoflagellates produce toxins.

Red tides

Rapid multiplication of certain red-coloured dinoflagellates can cause red tides.

Some species release toxins that may kill fish and other marine animals.

2.20 Euglenoids

Euglenoids are mostly freshwater organisms.

Important example:

Euglena

They possess a flexible covering called a:

Pellicle

The pellicle provides flexibility.

Nutrition

Euglenoids can show both:

Photosynthetic/autotrophic nutrition

Heterotrophic nutrition

Therefore, they are often described as mixotrophic.

2.21 Slime Moulds

Slime moulds are saprophytic protists.

They generally feed on:

Decaying organic matter

Microorganisms

Under favourable conditions they form a multinucleate mass called a plasmodium.

Under unfavourable conditions they may form fruiting structures that produce spores.

2.22 Protozoans

Protozoans are animal-like protists.

They are generally heterotrophic.

Important groups include:

Amoeboid protozoans

They move using pseudopodia.

Example:

Amoeba

Flagellated protozoans

They possess flagella.

Example:

Trypanosoma

Ciliated protozoans

They possess cilia.

Example:

Paramecium

Sporozoans

They generally possess an infectious spore-like stage.

Example:

Plasmodium

Plasmodium causes malaria.

2.23 KINGDOM FUNGI

Fungi are:

Eukaryotic

Heterotrophic

Mostly multicellular

Non-photosynthetic

Their cell wall is primarily composed of:

Chitin

Their nutrition is generally absorptive.

2.24 Fungal Body

The body of a fungus consists of thread-like structures called:

Hyphae

A network of hyphae is called:

Mycelium

Hyphae may be:

Septate

Aseptate/coenocytic

2.25 Fungal Nutrition

Fungi may be:

Saprophytic

Parasitic

Symbiotic

Saprophytic fungi

Obtain nutrients from dead and decaying organic matter.

Parasitic fungi

Obtain nutrients from living hosts.

Symbiotic fungi

Live in association with other organisms.

Examples include:

Lichens

Mycorrhiza

2.26 Fungal Reproduction

Fungi reproduce by:

Vegetative methods

Fragmentation

Fission

Budding

Asexual reproduction

Common asexual spores include:

Conidia

Sporangiospores

Zoospores

Sexual reproduction

The three major events are:

1. Plasmogamy
2. Karyogamy
3. Meiosis

2.27 Plasmogamy

Fusion of the protoplasm of two compatible cells is called:

Plasmogamy

2.28 Karyogamy

Fusion of two nuclei is called:

Karyogamy

2.29 Meiosis

Meiosis restores the haploid condition and leads to the formation of haploid sexual spores in fungi.

NEET sequence

Plasmogamy → Karyogamy → Meiosis

However, the timing between these events varies among fungal groups.

2.30 Major Groups of Fungi

For traditional NCERT/NEET classification, fungi are discussed under:

1. Phycomycetes
2. Ascomycetes
3. Basidiomycetes
4. Deuteromycetes

Phycomycetes

Important characteristics include:

Aseptate/coenocytic mycelium

Asexual spores commonly produced in sporangia

Sexual reproduction may occur

Examples:

Rhizopus

Mucor

Albugo

Rhizopus

Commonly known as:

Bread mould

2.31 Ascomycetes

Ascomycetes are commonly called:

Sac fungi

Sexual spores are called:

Ascospores

They are produced inside:

Asci

Examples:

Aspergillus

Penicillium

Saccharomyces

Claviceps

Neurospora

2.32 Basidiomycetes

Basidiomycetes are commonly called:

Club fungi

Sexual spores are:

Basidiospores

They are produced externally on:

Basidia

Examples:

Agaricus

Ustilago

Puccinia

Important associations

Agaricus → Mushroom

Ustilago → Smut

Puccinia → Rust

2.33 Deuteromycetes

Deuteromycetes are commonly called:

Imperfect fungi

The term reflects the fact that the sexual stage was not known for the fungi placed in this group in the traditional classification.

They reproduce primarily through asexual spores.

Examples include:

Alternaria

Colletotrichum

Trichoderma

2.34 LICHENS

Lichens represent a symbiotic association between:

Alga + Fungus

The algal partner is called the:

Phycobiont

The fungal partner is called the:

Mycobiont

Functions

The algal partner:

Performs photosynthesis.

Provides organic food.

The fungal partner:

Provides shelter.

Helps absorb water and minerals.

NEET point

Lichens are good indicators of air pollution, particularly because they are sensitive to atmospheric pollutants.

2.35 MYCORRHIZA

Mycorrhiza represents a symbiotic association between:

Fungus + Roots of higher plants

The fungus helps in:

Water absorption

Mineral absorption, especially phosphorus

The plant provides organic nutrients to the fungus.

2.36 KINGDOM PLANTAE

Plants are:

Eukaryotic

Multicellular

Primarily autotrophic

Usually photosynthetic

Possess cellulose-containing cell walls

Their reserve food is generally:

Starch

2.37 KINGDOM ANIMALIA

Animals are:

Eukaryotic

Multicellular

Heterotrophic

Generally ingestive in nutrition

Without cell walls

2.38 VIRUSES

Viruses are acellular infectious entities.

They do not have a typical cellular organisation.

A virus generally consists of:

Genetic material

Protein coat

The genetic material may be:

DNA

RNA

A virus generally contains either DNA or RNA as its genetic material, not both as its genomic material.

2.39 Viral Nature

Viruses show a unique position between living and non-living systems.

Outside a host cell, they may behave like non-living particles.

Inside a suitable host cell, they replicate using the host’s machinery.

Important properties

Viruses:

Lack cellular organisation.

Lack independent metabolism.

Cannot reproduce independently outside a suitable host.

Can be crystallised in certain circumstances.

2.40 Bacteriophages

Viruses that infect bacteria are called:

Bacteriophages

They are also called:

Phages

2.41 VIROIDS

Viroids are smaller infectious agents than viruses.

They consist of:

Small circular RNA molecules without a protein coat.

They primarily cause diseases in plants.

Important example:

Potato spindle tuber disease

NEET key point

Viroid = naked infectious RNA.

2.42 PRIONS

Prions are infectious protein particles.

They are associated with certain neurodegenerative diseases.

Examples include:

Scrapie

Bovine spongiform encephalopathy (BSE), commonly called mad cow disease

Creutzfeldt–Jakob disease

Key distinction

Agent	Basic nature
Virus	Nucleic acid + protein coat
Viroid	Naked RNA
Prion	Infectious protein

2.43 MOST IMPORTANT NEET ONE-LINERS

1. Five-kingdom classification → R.H. Whittaker
2. Five kingdoms proposed → 1969
3. Monera → Prokaryotic
4. Protista → Mainly unicellular eukaryotes
5. Fungi cell wall → Chitin
6. Plant cell wall → Cellulose
7. Mycoplasma → Wall-less bacteria
8. Archaebacteria → Distinctive cell-wall chemistry
9. Methanogens → Methane production
10. Cyanobacteria → Photosynthetic bacteria
11. Heterocysts → Nitrogen fixation in certain cyanobacteria
12. Euglena → Mixotrophic
13. Diatoms → Silica-containing cell walls
14. Red tide → Certain dinoflagellates
15. Plasmodium → Sporozoan
16. Fungal body → Mycelium
17. Hyphal network → Mycelium
18. Fungal cell wall → Chitin
19. Plasmogamy → Fusion of protoplasm
20. Karyogamy → Fusion of nuclei
21. Ascomycetes → Ascospores
22. Basidiomycetes → Basidiospores
23. Agaricus → Mushroom
24. Ustilago → Smut
25. Puccinia → Rust
26. Rhizopus → Bread mould
27. Lichen → Alga + fungus
28. Mycorrhiza → Fungus + plant root
29. Virus → Acellular infectious entity
30. Bacteriophage → Virus infecting bacteria
31. Viroid → Naked infectious RNA
32. Prion → Infectious protein

PART B — NEET/AIPMT PREVIOUS-YEAR QUESTION BANK

PYQ 1 — Five Kingdom Classification

Exam: AIPMT 2009

The five-kingdom classification system was proposed by:

A. Linnaeus
B. R.H. Whittaker
C. Ernst Haeckel
D. Aristotle

Answer: B. R.H. Whittaker

Explanation: R.H. Whittaker proposed the five-kingdom classification in 1969. The kingdoms are Monera, Protista, Fungi, Plantae and Animalia.

PYQ 2 — Archaebacteria

Exam: AIPMT 2010

Archaebacteria differ from eubacteria particularly in their:

A. Nucleus
B. Ribosomes
C. Cell-wall composition
D. Genetic material

Answer: C. Cell-wall composition

Explanation: Archaebacteria possess a distinctive cell-wall composition different from the typical peptidoglycan-containing wall of eubacteria.

PYQ 3 — Five Kingdom Criteria

Exam: NEET 2026

Which set represents important criteria used by Whittaker for five-kingdom classification?

A. Cell structure, body organisation, nutrition, reproduction and phylogeny
B. Only habitat and reproduction
C. Only cell size and shape
D. Only locomotion and habitat

Answer: A

Explanation: Whittaker’s classification considered cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships.

PYQ 4 — Complexity of Body Organisation

Exam: NEET 2025

Arrange the kingdoms represented by the following descriptions in increasing complexity:

Prokaryotic organisms

Unicellular eukaryotes

Multicellular fungi

Plants

Animals

A. Monera → Protista → Fungi → Plantae → Animalia
B. Protista → Monera → Fungi → Animalia → Plantae
C. Monera → Fungi → Protista → Plantae → Animalia
D. Fungi → Monera → Protista → Animalia → Plantae

Answer: A

Explanation: The progression begins with prokaryotic organisation in Monera, followed by unicellular eukaryotic organisation in Protista, then multicellular fungal organisation and finally the more complex tissue/organ organisation of plants and animals. The 2025 PYQ specifically tested this increasing-complexity concept.

PYQ 5 — Archaebacteria

Exam: NEET 2017

Archaebacteria are particularly notable because many members can survive:

A. Only in freshwater
B. Only inside animals
C. Extreme environmental conditions
D. Only in oxygen-rich environments

Answer: C. Extreme environmental conditions

Explanation: Archaebacteria include halophiles, thermoacidophiles and methanogens, many of which occupy unusual or extreme habitats.

PYQ 6 — Mycoplasma

Exam: NEET 2020

The distinctive feature of Mycoplasma is:

A. Absence of DNA
B. Absence of cell wall
C. Presence of mitochondria
D. Presence of a true nucleus

Answer: B. Absence of cell wall

Explanation: Mycoplasma are wall-less bacteria. They possess a plasma membrane but lack the typical bacterial cell wall.

PYQ 7 — Mycoplasma Statements

Exam: NEET 2022 Phase 1

Consider:

Statement I: Mycoplasma can pass through very fine filters.
Statement II: Mycoplasma possess a cell wall.

A. Both statements are correct
B. Both statements are incorrect
C. I is correct, II is incorrect
D. I is incorrect, II is correct

Answer: C

Explanation: Mycoplasma are exceptionally small and lack a cell wall. This is why the second statement is incorrect.

PYQ 8 — Protista Nutrition

Exam: NEET 2024 Re-Examination

Match:

Euglenoid

Dinoflagellate

Slime mould

Plasmodium

with their major nutritional modes.

Answer: Euglenoids can switch between photosynthetic and heterotrophic nutrition; dinoflagellates are commonly photosynthetic; slime moulds are saprophytic; Plasmodium is parasitic.

Explanation: This question tests the nutritional diversity within Protista.

PYQ 9 — Fungi Identification

Exam: NEET 2024

Match the following:

Organism	Common identity
Rhizopus	Bread mould
Ustilago	Smut
Puccinia	Rust
Agaricus	Mushroom

Answer: All four pairings are correctly matched.

Explanation: These are classic NCERT examples of fungal groups/organisms and are important for NEET identification questions.

PYQ 10 — Fungal Classification

Exam: NEET 2024

Which of the following is not used as a major criterion for traditional classification of fungi?

A. Mycelial organisation
B. Spore formation
C. Fruiting structures
D. Presence of chlorophyll

Answer: D. Presence of chlorophyll

Explanation: Fungi are non-photosynthetic organisms and lack chlorophyll. Traditional classification focuses on mycelial characteristics and reproductive structures, particularly spores.

PYQ 11 — Prions

Exam: NEET 2022 Phase 2

Mad cow disease and Creutzfeldt–Jakob disease are associated with:

A. Viroids
B. Prions
C. Bacteriophages
D. Protozoans

Answer: B. Prions

Explanation: Prions are infectious protein particles associated with transmissible neurodegenerative disorders, including BSE and Creutzfeldt–Jakob disease.

PYQ 12 — Viroids

Exam: NEET 2020 Phase 1

Viroids are best described as:

A. DNA enclosed in a protein coat
B. RNA enclosed in a protein coat
C. Small naked infectious RNA molecules
D. Infectious proteins

Answer: C. Small naked infectious RNA molecules

Explanation: Viroids are much simpler than viruses and consist of small infectious RNA molecules without a protein coat.

PYQ 13 — Scientific Name

Exam: NEET 2019

Which represents the correctly written scientific name of mango?

A. Mangifera Indica
B. mangifera indica
C. Mangifera indica
D. MANGIFERA INDICA

Answer: C. Mangifera indica

Explanation: In binomial nomenclature, the genus begins with a capital letter, the species name begins with a lowercase letter, and the complete scientific name is conventionally italicised when typed. The question database identifies this as a NEET 2019 PYQ.

PYQ 14 — Prokaryotes

Exam: NEET 2018

Which organism is not a prokaryote?

A. Bacterium
B. Cyanobacterium
C. Mycoplasma
D. Protozoan

Answer: D. Protozoan

Explanation: Bacteria, cyanobacteria and Mycoplasma are prokaryotic, whereas protozoans are eukaryotic organisms.

PYQ 15 — Cyanobacteria

Exam: NEET 2018

Which statement concerning cyanobacteria is correct?

A. They are eukaryotic algae
B. They are photosynthetic prokaryotes
C. They lack photosynthetic pigments
D. They possess chloroplasts

Answer: B. They are photosynthetic prokaryotes

Explanation: Cyanobacteria are bacteria capable of photosynthesis and do not possess chloroplasts.

PYQ 16 — Protozoans

Exam: NEET 2018

Ciliates differ from other major protozoan groups mainly because they possess:

A. Pseudopodia
B. Numerous cilia
C. Only spores
D. Cell walls made of chitin

Answer: B. Numerous cilia

Explanation: Cilia are the characteristic locomotory structures of ciliates. Paramecium is a classic example.

PYQ 17 — Basidiomycetes

Exam: NEET 2018

After karyogamy and meiosis, basidiomycetes produce sexual spores:

A. Inside asci
B. Externally on basidia
C. Inside sporangia
D. Inside conidiophores

Answer: B. Externally on basidia

Explanation: Basidiomycetes produce basidiospores externally on basidia.

PYQ 18 — Chief Producers in Oceans

Exam: NEET 2018

The organisms that constitute important primary producers in oceans include:

A. Diatoms
B. Protozoans
C. Slime moulds
D. Fungi

Answer: A. Diatoms

Explanation: Diatoms are photosynthetic organisms and are major components of marine phytoplankton.

REPEATED / FREQUENTLY TESTED CONCEPTS

REPEATED CONCEPT — Mycoplasma

Asked in: NEET 2020, NEET 2022 Phase 1

Core fact:
Mycoplasma lacks a cell wall.

REPEATED CONCEPT — Five Kingdom Classification

Asked in: AIPMT 2009, NEET 2025 and other papers

Core fact:
R.H. Whittaker → Five Kingdom Classification → 1969

REPEATED CONCEPT — Fungal Identification

Asked repeatedly across NEET/AIPMT papers

Remember:

Rhizopus → Bread mould
Agaricus → Mushroom
Ustilago → Smut
Puccinia → Rust

REPEATED CONCEPT — Viruses / Viroids / Prions

These distinctions have been repeatedly tested:

Virus → Nucleic acid + protein coat
Viroid → Naked RNA
Prion → Infectious protein

PYQ 19 — Archaebacteria

Exam: AIPMT 2014

Archaebacteria differ from eubacteria mainly in their:

A. Cell wall composition
B. Nuclear membrane
C. Ribosomes
D. DNA composition

Answer: A. Cell wall composition

Explanation: Archaebacteria possess a distinctive cell-wall composition and membrane chemistry. Their cell walls do not have the typical peptidoglycan characteristic of eubacteria.

Repeated concept: AIPMT 2010 + AIPMT 2014

PYQ 20 — Motility in Bacteria

Exam: AIPMT 2014

Motile bacteria generally move with the help of:

A. Pili
B. Flagella
C. Fimbriae
D. Capsule

Answer: B. Flagella

Explanation: Bacterial flagella are specialised structures involved primarily in locomotion. A bacterial flagellum consists of a filament, hook and basal body.

PYQ 21 — Five-Kingdom Classification

Exam: AIPMT 2014

Which of the following is not a major basis of R.H. Whittaker’s five-kingdom classification?

A. Cell structure
B. Mode of nutrition
C. Body organisation
D. Presence of flagella

Answer: D. Presence of flagella

Explanation: Whittaker considered cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships. Presence of flagella was not a principal criterion.

Repeated concept: This concept is again tested in NEET 2026.

PYQ 22 — Virus Structure

Exam: AIPMT 2014

The protein coat surrounding the nucleic acid of a virus is called:

A. Capsid
B. Capsule
C. Cell wall
D. Envelope

Answer: A. Capsid

Explanation: The viral genetic material is enclosed by a protein coat called the capsid. The capsid is composed of protein subunits called capsomeres.

PYQ 23 — Anoxygenic Photosynthesis

Exam: AIPMT 2014

Anoxygenic photosynthesis is characteristic of:

A. Cyanobacteria
B. Green plants
C. Purple and green photosynthetic bacteria
D. Diatoms

Answer: C. Purple and green photosynthetic bacteria

Explanation: Certain photosynthetic bacteria perform anoxygenic photosynthesis, in which oxygen is not released as a by-product.

PYQ 24 — Archaebacterial Habitat

Exam: NEET 2017

Which group of organisms is particularly adapted to extreme saline conditions?

A. Methanogens
B. Halophiles
C. Cyanobacteria
D. Mycoplasma

Answer: B. Halophiles

Explanation: Halophiles are archaebacteria adapted to environments containing very high concentrations of salt.

Exam connection: The chapter database records this as a NEET 2017 question.

PYQ 25 — Viroids

Exam: NEET 2017

Viroids differ from viruses because viroids possess:

A. DNA with a protein coat
B. RNA with a protein coat
C. RNA without a protein coat
D. DNA without a protein coat

Answer: C. RNA without a protein coat

Explanation: Viroids are extremely small infectious agents consisting of naked RNA, without the protein coat found in viruses.

Repeated concept: Viroids were tested again in NEET 2020.

PYQ 26 — Mycoplasma

Exam: NEET 2017

Which organism is among the smallest known living cells and lacks a definite cell wall?

A. Nostoc
B. Mycoplasma
C. Rhizopus
D. Euglena

Answer: B. Mycoplasma

Explanation: Mycoplasma are extremely small bacteria and characteristically lack a cell wall. They can survive under anaerobic conditions.

Repeated: Mycoplasma was also tested in NEET 2020 and NEET 2022 Phase 1.

PYQ 27 — Bacterial Capsule

Exam: NEET 2017

Which bacterial structure provides a sticky character and can assist attachment?

A. Capsule/slime layer
B. Ribosome
C. Nucleoid
D. Mesosome

Answer: A. Capsule/slime layer

Explanation: Some bacteria possess a capsule or slime layer outside the cell wall. It can help in adhesion and may provide protection.

PYQ 28 — Fungi

Exam: NEET 2016 Phase 2

Which statement is incorrect regarding fungi?

A. They are heterotrophic
B. Their cell wall contains chitin
C. They are photosynthetic
D. They may reproduce sexually and asexually

Answer: C. They are photosynthetic

Explanation: Fungi lack chlorophyll and are heterotrophic. They obtain nutrients by absorption.

PYQ 29 — Methanogens

Exam: NEET 2016 Phase 2

Methanogens belong to:

A. Eubacteria
B. Archaebacteria
C. Cyanobacteria
D. Protista

Answer: B. Archaebacteria

Explanation: Methanogens are archaebacteria that produce methane under anaerobic conditions. They are found in marshy environments and in the rumen of ruminants.

Repeated concept: Methanogens were also tested in AIPMT 2010, AIPMT 2016 and other papers.

PYQ 30 — Protista

Exam: NEET 2016 Phase 1

Chrysophytes, Euglenoids, Dinoflagellates and Slime Moulds are placed in:

A. Monera
B. Protista
C. Fungi
D. Plantae

Answer: B. Protista

Explanation: These groups are included under Kingdom Protista in the NCERT five-kingdom classification.

PYQ 31 — Viroids

Exam: NEET 2016 Phase 1

Which statement about viroids is incorrect?

A. They are smaller than viruses
B. They consist of RNA
C. They possess a protein coat
D. They can cause plant diseases

Answer: C. They possess a protein coat

Explanation: Viroids consist of small circular RNA molecules without a protein coat.

Repeated: Viroids → NEET 2016 + 2017 + 2020.

PYQ 32 — Fungal Cell Wall

Exam: NEET 2016 Phase 1

A major component of the cell wall of most fungi is:

A. Cellulose
B. Chitin
C. Peptidoglycan
D. Silica

Answer: B. Chitin

Explanation: The fungal cell wall is primarily composed of chitin.

Repeated concept: Fungal cell wall → repeatedly tested.

PYQ 33 — Methanogens and Biogas

Exam: NEET 2016 Phase 1

The primitive prokaryotes responsible for methane production from the dung of ruminants belong to:

A. Cyanobacteria
B. Methanogens
C. Mycoplasma
D. Eubacteria

Answer: B. Methanogens

Explanation: Methanogens produce methane during anaerobic decomposition and are important in biogas production.

Repeated concept: Methanogens.

PYQ 34 — Pili and Fimbriae

Exam: AIPMT 2015

Structures that help certain bacteria attach to rocks or host tissues are:

A. Flagella
B. Fimbriae
C. Ribosomes
D. Mesosomes

Answer: B. Fimbriae

Explanation: Fimbriae are short, hair-like structures that help bacteria attach to surfaces. Pili can have additional roles, including conjugation.

PYQ 35 — Diatoms

Exam: AIPMT 2015

In which organisms do cell walls form two thin overlapping shells that fit together?

A. Dinoflagellates
B. Diatoms
C. Euglenoids
D. Protozoans

Answer: B. Diatoms

Explanation: Diatoms possess a characteristic silica-containing cell wall consisting of two overlapping halves, resembling a box with a lid.

Repeated concept: Diatom cell wall → NEET 2019 and NEET 2022 also tested this concept.

PYQ 36 — Cell Wall Absence

Exam: AIPMT 2015

Cell wall is absent in:

A. Mycoplasma
B. Cyanobacteria
C. Fungi
D. Eubacteria

Answer: A. Mycoplasma

Explanation: Mycoplasma are unusual bacteria because they lack a cell wall.

Repeated: Mycoplasma → multiple years.

PYQ 37 — Deuteromycetes

Exam: AIPMT 2015

The imperfect fungi that act as decomposers and contribute to mineral cycling belong to:

A. Phycomycetes
B. Ascomycetes
C. Deuteromycetes
D. Basidiomycetes

Answer: C. Deuteromycetes

Explanation: Deuteromycetes were traditionally called fungi imperfecti because their sexual reproductive stage was not known.

PYQ 38 — True Nucleus

Exam: AIPMT 2015 Cancelled Paper

True nucleus is absent in:

A. Amoeba
B. Bacteria
C. Euglena
D. Paramecium

Answer: B. Bacteria

Explanation: Bacteria are prokaryotes and therefore lack a membrane-bound true nucleus.

PYQ 39 — Viruses

Exam: AIPMT 2014

Viruses possess:

A. Both DNA and RNA as genetic material
B. Either DNA or RNA as genetic material
C. Only DNA
D. Only RNA

Answer: B. Either DNA or RNA as genetic material

Explanation: A virus contains either DNA or RNA as its genetic material, enclosed by a protein coat.

PYQ 40 — Bacterial Respiration

Exam: AIPMT 2014

Which structures perform functions analogous to mitochondria in bacteria?

A. Mesosomes
B. Ribosomes
C. Lysosomes
D. Golgi bodies

Answer: A. Mesosomes

Explanation: Mesosomes were described in older NCERT material as infoldings of the plasma membrane associated with respiration and other functions.
Important modern note: The mesosome is now regarded as an artefact of chemical fixation rather than a genuine bacterial organelle. For historical PYQs, however, the expected answer is mesosome.

HIGH-FREQUENCY REPEATED CONCEPTS SO FAR

Concept	Exams/Papers
Mycoplasma lacks cell wall	NEET 2017, NEET 2020, NEET 2022 Phase 1
Viroid = naked RNA	NEET 2016, NEET 2017, NEET 2020
Methanogens	NEET 2016, AIPMT 2010 and others
Archaebacteria vs eubacteria	AIPMT 2010, AIPMT 2014
Diatom silica wall	AIPMT 2015, NEET 2019, NEET 2022
Whittaker classification criteria	AIPMT 2014, NEET 2026
Fungal cell wall = chitin	NEET 2016 and repeated
Protista groups	NEET 2016 and repeated
Bacteriophage/virus concepts	Multiple AIPMT/NEET papers

PYQ 41 — Kingdom Monera

Exam: AIPMT 2013

Which of the following groups contains only prokaryotic organisms?

A. Bacteria and cyanobacteria
B. Fungi and bacteria
C. Protozoans and bacteria
D. Cyanobacteria and fungi

Answer: A. Bacteria and cyanobacteria

Explanation: Bacteria and cyanobacteria are prokaryotes. They lack a membrane-bound nucleus and membrane-bound organelles.

PYQ 42 — Cyanobacteria

Exam: AIPMT 2013

Cyanobacteria are also commonly known as:

A. Golden algae
B. Blue-green algae
C. Brown algae
D. Red algae

Answer: B. Blue-green algae

Explanation: Cyanobacteria were historically called blue-green algae because of their photosynthetic pigments. However, they are prokaryotic bacteria, not true algae.

PYQ 43 — Nitrogen Fixation

Exam: AIPMT 2013

Which specialised cells of some cyanobacteria are associated with atmospheric nitrogen fixation?

A. Conidia
B. Heterocysts
C. Basidia
D. Asci

Answer: B. Heterocysts

Explanation: Heterocysts are specialised nitrogen-fixing cells found in cyanobacteria such as Nostoc and Anabaena.

PYQ 44 — Protista

Exam: AIPMT 2013

Which of the following is a characteristic feature of Kingdom Protista?

A. All organisms are multicellular
B. All organisms are prokaryotic
C. Members are primarily unicellular eukaryotes
D. Cell wall is always made of chitin

Answer: C. Members are primarily unicellular eukaryotes

Explanation: Protista mainly includes unicellular eukaryotic organisms. They possess a true nucleus and membrane-bound organelles.

PYQ 45 — Dinoflagellates

Exam: AIPMT 2013

Red tides in marine ecosystems are commonly associated with rapid multiplication of:

A. Diatoms
B. Dinoflagellates
C. Euglenoids
D. Slime moulds

Answer: B. Dinoflagellates

Explanation: Certain dinoflagellates multiply rapidly and may produce coloured substances and toxins, producing the phenomenon known as red tide.

Repeated concept: Red tide/dinoflagellates has been tested in multiple NEET/AIPMT papers.

PYQ 46 — Euglenoids

Exam: AIPMT 2013

The flexible covering present around Euglena is called:

A. Capsule
B. Pellicle
C. Cell wall
D. Cuticle

Answer: B. Pellicle

Explanation: Euglenoids possess a flexible protein-rich covering called a pellicle, which allows them to change their body shape.

PYQ 47 — Euglena Nutrition

Exam: AIPMT 2013

Euglena is considered mixotrophic because it can:

A. Only ingest food
B. Only perform photosynthesis
C. Show both autotrophic and heterotrophic nutrition
D. Only absorb minerals

Answer: C. Show both autotrophic and heterotrophic nutrition

Explanation: In the presence of light, Euglena can perform photosynthesis. Under unsuitable conditions, it can obtain organic nutrients heterotrophically.

PYQ 48 — Diatoms

Exam: AIPMT 2013

The cell walls of diatoms are mainly impregnated with:

A. Chitin
B. Silica
C. Cellulose
D. Peptidoglycan

Answer: B. Silica

Explanation: Diatom cell walls contain silica and form two overlapping shells. Their accumulated deposits form diatomaceous earth.

Repeated: This is a high-frequency Biological Classification concept.

PYQ 49 — Diatomaceous Earth

Exam: AIPMT 2013

Diatomaceous earth is formed mainly from the remains of:

A. Dinoflagellates
B. Diatoms
C. Euglenoids
D. Protozoans

Answer: B. Diatoms

Explanation: The silica-rich remains of dead diatoms accumulate over long periods to form diatomaceous earth.

PYQ 50 — Slime Moulds

Exam: AIPMT 2013

Slime moulds are generally:

A. Autotrophic
B. Saprophytic
C. Photosynthetic bacteria
D. Parasitic fungi

Answer: B. Saprophytic

Explanation: Slime moulds obtain nutrients from dead and decaying organic matter and microorganisms.

PYQ 51 — Plasmodium

Exam: AIPMT 2013

Plasmodium belongs to which group of protozoans?

A. Amoeboid protozoans
B. Flagellated protozoans
C. Ciliated protozoans
D. Sporozoans

Answer: D. Sporozoans

Explanation: Plasmodium is traditionally placed among sporozoans and is the causative organism of malaria.

PYQ 52 — Amoeboid Protozoans

Exam: AIPMT 2013

Amoeboid protozoans move with the help of:

A. Cilia
B. Flagella
C. Pseudopodia
D. Basidia

Answer: C. Pseudopodia

Explanation: Amoeboid protozoans such as Amoeba move and capture food using temporary cytoplasmic projections called pseudopodia.

PYQ 53 — Ciliated Protozoans

Exam: AIPMT 2013

Which organism is a typical example of a ciliated protozoan?

A. Amoeba
B. Trypanosoma
C. Paramecium
D. Plasmodium

Answer: C. Paramecium

Explanation: Paramecium possesses numerous cilia used for locomotion and feeding.

PYQ 54 — Flagellated Protozoans

Exam: AIPMT 2013

Trypanosoma is an example of:

A. Amoeboid protozoan
B. Flagellated protozoan
C. Ciliated protozoan
D. Sporozoan

Answer: B. Flagellated protozoan

Explanation: Trypanosoma possesses a flagellum and is traditionally classified among flagellated protozoans.

KINGDOM FUNGI — PYQs

PYQ 55 — Fungal Nutrition

Exam: AIPMT 2013

Fungi generally obtain their nutrition by:

A. Ingestion
B. Absorption
C. Photosynthesis
D. Chemosynthesis

Answer: B. Absorption

Explanation: Fungi secrete digestive enzymes onto their food source and absorb the resulting soluble nutrients. Thus, their nutrition is primarily absorptive heterotrophic nutrition.

PYQ 56 — Fungal Hyphae

Exam: AIPMT 2013

The thread-like structures constituting the fungal body are called:

A. Hyphae
B. Asci
C. Basidia
D. Conidia

Answer: A. Hyphae

Explanation: Individual thread-like structures are called hyphae, while a network of hyphae is called mycelium.

PYQ 57 — Mycelium

Exam: AIPMT 2013

A network of fungal hyphae is called:

A. Mycelium
B. Plasmodium
C. Protonema
D. Rhizoid

Answer: A. Mycelium

Explanation: Mycelium is the vegetative body of most fungi and consists of a network of hyphae.

PYQ 58 — Fungal Cell Wall

Exam: AIPMT 2013

The fungal cell wall is mainly composed of:

A. Cellulose
B. Chitin
C. Peptidoglycan
D. Silica

Answer: B. Chitin

Explanation: Chitin is the characteristic major structural component of the fungal cell wall.

Repeated concept: This has appeared in several NEET/AIPMT papers.

PYQ 59 — Asexual Spores

Exam: AIPMT 2013

Asexual spores produced externally on specialised structures in many fungi are called:

A. Conidia
B. Ascospores
C. Basidiospores
D. Zygospores

Answer: A. Conidia

Explanation: Conidia are asexual spores produced externally on specialised hyphae called conidiophores.

PYQ 60 — Ascomycetes

Exam: AIPMT 2013

Sexual spores of Ascomycetes are called:

A. Basidiospores
B. Ascospores
C. Conidia
D. Zoospores

Answer: B. Ascospores

Explanation: Ascomycetes produce sexual spores called ascospores, which are formed inside sac-like structures called asci.

PYQ 61 — Basidiomycetes

Exam: AIPMT 2013

Sexual spores of Basidiomycetes are called:

A. Ascospores
B. Basidiospores
C. Conidia
D. Sporangiospores

Answer: B. Basidiospores

Explanation: Basidiomycetes produce basidiospores externally on basidia.

PYQ 62 — Agaricus

Exam: AIPMT 2013

Agaricus is commonly known as:

A. Bread mould
B. Mushroom
C. Rust
D. Smut

Answer: B. Mushroom

Explanation: Agaricus includes common edible mushrooms and belongs to Basidiomycetes.

PYQ 63 — Puccinia

Exam: AIPMT 2013

Puccinia is associated with:

A. Rust disease
B. Smut disease
C. Bread mould
D. Malaria

Answer: A. Rust disease

Explanation: Puccinia is a rust fungus and belongs to Basidiomycetes.

PYQ 64 — Ustilago

Exam: AIPMT 2013

Ustilago is commonly associated with:

A. Rust
B. Smut
C. Mushroom
D. Bread mould

Answer: B. Smut

Explanation: Ustilago is a smut fungus belonging to Basidiomycetes.

PYQ 65 — Rhizopus

Exam: AIPMT 2013

Rhizopus is commonly called:

A. Bread mould
B. Rust
C. Smut
D. Mushroom

Answer: A. Bread mould

Explanation: Rhizopus is a common bread mould and is traditionally included among Phycomycetes.

PYQ 66 — Deuteromycetes

Exam: AIPMT 2013

Deuteromycetes are commonly known as:

A. Perfect fungi
B. Imperfect fungi
C. Club fungi
D. Sac fungi

Answer: B. Imperfect fungi

Explanation: Deuteromycetes were traditionally called imperfect fungi because their sexual reproductive stage was unknown.

PYQ 67 — Lichens

Exam: AIPMT 2013

Lichens represent a symbiotic association between:

A. Fungus and bacterium
B. Alga and fungus
C. Fungus and virus
D. Alga and protozoan

Answer: B. Alga and fungus

Explanation: A lichen consists of an algal partner (phycobiont) and a fungal partner (mycobiont) living in symbiotic association.

PYQ 68 — Air Pollution Indicator

Exam: AIPMT 2013

Lichens are considered good indicators of:

A. Water pollution
B. Soil pollution
C. Air pollution
D. Noise pollution

Answer: C. Air pollution

Explanation: Lichens are highly sensitive to atmospheric pollutants, particularly sulphur dioxide, and therefore can serve as indicators of air pollution.

Repeated concept: Lichens and air pollution are repeatedly tested.

PYQ 69 — Mycorrhiza

Exam: AIPMT 2013

Mycorrhiza represents an association between:

A. Algae and fungi
B. Fungi and plant roots
C. Bacteria and roots
D. Protozoans and roots

Answer: B. Fungi and plant roots

Explanation: Mycorrhiza is a mutualistic association between fungal hyphae and plant roots. The fungus helps the plant obtain water and minerals, particularly phosphorus.

PYQ 70 — Plasmogamy

Exam: AIPMT 2013

Fusion of the cytoplasm of two compatible fungal cells is called:

A. Karyogamy
B. Plasmogamy
C. Meiosis
D. Sporulation

Answer: B. Plasmogamy

Explanation: Plasmogamy = fusion of protoplasm/cytoplasm, whereas karyogamy = fusion of nuclei.

PYQ 71 — Karyogamy

Exam: AIPMT 2013

Fusion of two fungal nuclei is called:

A. Plasmogamy
B. Karyogamy
C. Budding
D. Fragmentation

Answer: B. Karyogamy

Explanation: During karyogamy, two compatible nuclei fuse to form a diploid nucleus.

PYQ 72 — Sequence in Sexual Reproduction

Exam: AIPMT 2013

The correct sequence in fungal sexual reproduction is:

A. Karyogamy → plasmogamy → meiosis
B. Plasmogamy → karyogamy → meiosis
C. Meiosis → plasmogamy → karyogamy
D. Plasmogamy → meiosis → karyogamy

Answer: B. Plasmogamy → karyogamy → meiosis

Explanation: The general sequence is:

Plasmogamy → Karyogamy → Meiosis

The timing between these stages varies among fungal groups.

PYQ 73 — Virus

Exam: AIPMT 2013

Viruses are best described as:

A. Unicellular organisms
B. Acellular infectious entities
C. Prokaryotic cells
D. Eukaryotic cells

Answer: B. Acellular infectious entities

Explanation: Viruses lack cellular organisation. They contain genetic material surrounded by a protein coat and replicate only within suitable host cells.

PYQ 74 — Bacteriophage

Exam: AIPMT 2013

A virus that infects bacteria is called:

A. Viroid
B. Bacteriophage
C. Prion
D. Mycoplasma

Answer: B. Bacteriophage

Explanation: Bacteriophages, or phages, are viruses that infect bacterial cells.

PYQ 75 — Viral Genetic Material

Exam: AIPMT 2013

The genetic material of a virus may be:

A. Only DNA
B. Only RNA
C. DNA or RNA
D. DNA and RNA together in every virus

Answer: C. DNA or RNA

Explanation: Viral genomes can be composed of DNA or RNA. A particular virus has one type of nucleic acid as its genome.

PYQ 76 — Prions

Exam: AIPMT 2013

Prions are infectious agents made primarily of:

A. DNA
B. RNA
C. Protein
D. Lipid

Answer: C. Protein

Explanation: Prions are infectious protein particles and lack the nucleic acid genome characteristic of viruses.

PYQ 77 — Bovine Spongiform Encephalopathy

Exam: AIPMT 2013

Bovine spongiform encephalopathy is associated with:

A. Viroids
B. Prions
C. Bacteria
D. Cyanobacteria

Answer: B. Prions

Explanation: BSE, commonly known as mad cow disease, is associated with abnormal infectious proteins called prions.

Repeated concept: Prion-related diseases have appeared in multiple NEET papers.

PYQ 78 — Potato Spindle Tuber Disease

Exam: AIPMT 2013

Potato spindle tuber disease is caused by:

A. Virus
B. Viroid
C. Bacterium
D. Prion

Answer: B. Viroid

Explanation: Potato spindle tuber disease is caused by a viroid, a small circular naked RNA molecule.

Repeated: Viroid → repeatedly tested.

PYQ 79 — Prokaryotic Organisms

Exam: AIPMT 2012

Which of the following is a prokaryotic organism?

A. Amoeba
B. Euglena
C. Nostoc
D. Paramecium

Answer: C. Nostoc

Explanation: Nostoc is a cyanobacterium and therefore a prokaryote.

PYQ 80 — Cyanobacteria

Exam: AIPMT 2012

Which of the following organisms can perform oxygenic photosynthesis but lacks chloroplasts?

A. Cyanobacterium
B. Euglena
C. Mushroom
D. Paramecium

Answer: A. Cyanobacterium

Explanation: Cyanobacteria are photosynthetic prokaryotes. Because they are prokaryotic, they do not possess chloroplasts.

IMPORTANT REPEATED-CONCEPT REGISTER

By this point in the chapter, these are particularly important for your ebook:

Concept	Repeated in
Mycoplasma lacks cell wall	NEET 2017, 2020, 2022
Viroid = naked RNA	NEET 2016, 2017, 2020 and other papers
Prion = infectious protein	Multiple NEET/AIPMT papers
Diatom = silica wall	Multiple papers
Lichen = algae + fungus	Multiple papers
Lichen = air-pollution indicator	Multiple papers
Fungal wall = chitin	Multiple papers
Plasmogamy → Karyogamy → Meiosis	Multiple papers
Methanogens = archaebacteria	Multiple papers
Cyanobacteria = photosynthetic prokaryotes	Multiple papers
Heterocyst = nitrogen fixation	Multiple papers
Euglena = mixotrophic	Multiple papers
Red tide = dinoflagellates	Multiple papers

PYQ 81 — Archaebacteria

Exam: AIPMT 2012

Which group of organisms is commonly found in highly saline environments?

A. Methanogens
B. Halophiles
C. Cyanobacteria
D. Mycoplasma

Answer: B. Halophiles

Explanation: Halophiles are archaebacteria adapted to environments with very high salt concentration.

PYQ 82 — Thermoacidophiles

Exam: AIPMT 2012

Organisms capable of surviving high temperature and acidic conditions are called:

A. Halophiles
B. Methanogens
C. Thermoacidophiles
D. Cyanobacteria

Answer: C. Thermoacidophiles

Explanation: Thermoacidophiles are archaebacteria adapted to hot and acidic environments.

PYQ 83 — Methanogens

Exam: AIPMT 2012

Methanogens are commonly found in:

A. Human blood
B. Rumen of cattle
C. Leaf mesophyll
D. Marine algae

Answer: B. Rumen of cattle

Explanation: Methanogens occur in anaerobic environments, including the rumen of ruminant animals, where they contribute to methane production.

PYQ 84 — Bacterial Shape

Exam: AIPMT 2012

Comma-shaped bacteria are called:

A. Cocci
B. Bacilli
C. Vibrios
D. Spirilla

Answer: C. Vibrios

Explanation: Bacteria are commonly classified by shape:

Coccus → spherical

Bacillus → rod-shaped

Vibrio → comma-shaped

Spirillum → spiral-shaped

PYQ 85 — Rod-Shaped Bacteria

Exam: AIPMT 2012

Rod-shaped bacteria are called:

A. Cocci
B. Bacilli
C. Vibrios
D. Spirilla

Answer: B. Bacilli

Explanation: Bacilli are rod-shaped bacteria.

PYQ 86 — Spherical Bacteria

Exam: AIPMT 2012

Spherical bacteria are known as:

A. Cocci
B. Bacilli
C. Vibrios
D. Spirilla

Answer: A. Cocci

Explanation: Cocci are spherical or nearly spherical bacteria.

PYQ 87 — Bacterial Genetic Material

Exam: AIPMT 2012

In a typical bacterial cell, the genetic material is located in the:

A. Nucleus
B. Nucleoid region
C. Mitochondrion
D. Chloroplast

Answer: B. Nucleoid region

Explanation: Bacteria lack a membrane-bound nucleus. Their chromosome is located in a region called the nucleoid.

PYQ 88 — Bacterial Ribosomes

Exam: AIPMT 2012

The ribosomes of prokaryotic cells are:

A. 80S
B. 70S
C. 60S
D. 90S

Answer: B. 70S

Explanation: Prokaryotic ribosomes are 70S, consisting of 50S and 30S subunits.

PYQ 89 — Cyanobacteria

Exam: AIPMT 2012

Which of the following is a cyanobacterium?

A. Nostoc
B. Agaricus
C. Rhizopus
D. Paramecium

Answer: A. Nostoc

Explanation: Nostoc is a cyanobacterium capable of photosynthesis and, in suitable species, nitrogen fixation.

PYQ 90 — Heterocysts

Exam: AIPMT 2012

Heterocysts are characteristic specialised cells found in:

A. Rhizopus
B. Nostoc
C. Euglena
D. Paramecium

Answer: B. Nostoc

Explanation: Nostoc and Anabaena possess heterocysts associated with nitrogen fixation.

KINGDOM PROTISTA

PYQ 91 — Chrysophytes

Exam: AIPMT 2011

Diatoms belong to:

A. Chrysophytes
B. Dinoflagellates
C. Euglenoids
D. Slime moulds

Answer: A. Chrysophytes

Explanation: Diatoms are included among chrysophytes in the NCERT classification.

PYQ 92 — Diatomaceous Earth

Exam: AIPMT 2011

Diatomaceous earth is useful commercially because of its:

A. High protein content
B. Silica-rich nature
C. High nitrogen content
D. Chitin content

Answer: B. Silica-rich nature

Explanation: Diatom shells contain silica. Their accumulated remains form diatomaceous earth, which has applications in filtration, polishing and insulation.

PYQ 93 — Dinoflagellates

Exam: AIPMT 2011

The body covering of many dinoflagellates consists of:

A. Chitin plates
B. Cellulose plates
C. Peptidoglycan
D. Silica only

Answer: B. Cellulose plates

Explanation: Many dinoflagellates possess a cell wall containing cellulose plates.

PYQ 94 — Red Tide

Exam: AIPMT 2011

A sudden increase in the population of certain dinoflagellates can result in:

A. Green revolution
B. Red tide
C. Lichen formation
D. Diatomaceous earth

Answer: B. Red tide

Explanation: Certain dinoflagellates multiply rapidly and produce characteristic coloured blooms called red tides. Some species release toxins.

PYQ 95 — Euglenoids

Exam: AIPMT 2011

Euglenoids generally occur in:

A. Freshwater
B. Desert soil
C. Dry rocks
D. Highly saline oceans only

Answer: A. Freshwater

Explanation: Most euglenoids, including Euglena, are freshwater organisms.

PYQ 96 — Pellicle

Exam: AIPMT 2011

The pellicle of Euglena helps in:

A. Photosynthesis only
B. Maintaining flexibility of the body
C. Nitrogen fixation
D. Spore production

Answer: B. Maintaining flexibility of the body

Explanation: The pellicle is flexible and allows Euglena to change its body shape.

PYQ 97 — Slime Moulds

Exam: AIPMT 2011

During favourable conditions, slime moulds form a multinucleate structure called:

A. Mycelium
B. Plasmodium
C. Basidium
D. Ascocarp

Answer: B. Plasmodium

Explanation: Slime moulds can form a multinucleate, multinucleate mass called a plasmodium during their vegetative phase.

PYQ 98 — Protozoans

Exam: AIPMT 2011

Which protozoan group moves with the help of pseudopodia?

A. Ciliates
B. Amoeboid protozoans
C. Flagellates
D. Sporozoans

Answer: B. Amoeboid protozoans

Explanation: Amoeboid protozoans use pseudopodia for locomotion and food capture.

PYQ 99 — Trypanosoma

Exam: AIPMT 2011

Trypanosoma belongs to which group?

A. Amoeboid protozoans
B. Flagellated protozoans
C. Ciliated protozoans
D. Sporozoans

Answer: B. Flagellated protozoans

Explanation: Trypanosoma possesses a flagellum and is traditionally classified among flagellated protozoans.

PYQ 100 — Paramecium

Exam: AIPMT 2011

Paramecium is classified as a:

A. Ciliated protozoan
B. Flagellated protozoan
C. Amoeboid protozoan
D. Sporozoan

Answer: A. Ciliated protozoan

Explanation: Paramecium uses numerous cilia for locomotion and feeding.

PYQ 101 — Plasmodium

Exam: AIPMT 2011

Plasmodium is traditionally classified under:

A. Amoeboid protozoans
B. Flagellated protozoans
C. Ciliated protozoans
D. Sporozoans

Answer: D. Sporozoans

Explanation: Plasmodium is traditionally placed in the sporozoan group and causes malaria.

KINGDOM FUNGI

PYQ 102 — Fungal Mycelium

Exam: AIPMT 2011

The vegetative body of a fungus is generally known as:

A. Mycelium
B. Plasmodium
C. Protonema
D. Thallus only

Answer: A. Mycelium

Explanation: A fungal mycelium consists of a network of hyphae.

PYQ 103 — Septate Hyphae

Exam: AIPMT 2011

Hyphae divided into compartments by cross walls are called:

A. Coenocytic
B. Septate
C. Aseptate
D. Uninucleate

Answer: B. Septate

Explanation: Septate hyphae contain cross walls called septa that divide the hypha into compartments.

PYQ 104 — Coenocytic Hyphae

Exam: AIPMT 2011

Hyphae lacking septa and containing multinucleate cytoplasm are described as:

A. Septate
B. Coenocytic
C. Cellular
D. Diploblastic

Answer: B. Coenocytic

Explanation: Coenocytic/aseptate hyphae lack cross walls and contain continuous multinucleate cytoplasm.

PYQ 105 — Vegetative Reproduction in Fungi

Exam: AIPMT 2011

Vegetative reproduction in fungi may occur through:

A. Fragmentation
B. Budding
C. Fission
D. All of the above

Answer: D. All of the above

Explanation: Fungi can reproduce vegetatively through fragmentation, fission and budding, depending on the group.

PYQ 106 — Conidia

Exam: AIPMT 2011

Conidia are:

A. Sexual spores
B. Asexual spores
C. Bacterial cells
D. Viral particles

Answer: B. Asexual spores

Explanation: Conidia are non-motile asexual spores produced externally on specialised fungal structures.

PYQ 107 — Sporangiospores

Exam: AIPMT 2011

Sporangiospores are produced:

A. Inside sporangia
B. Inside asci
C. On basidia
D. Inside lichens

Answer: A. Inside sporangia

Explanation: As their name indicates, sporangiospores are spores produced within a sporangium.

PYQ 108 — Asci

Exam: AIPMT 2011

Ascospores are produced inside:

A. Basidia
B. Asci
C. Sporangia
D. Conidiophores

Answer: B. Asci

Explanation: In Ascomycetes, sexual spores called ascospores are formed within sac-like structures called asci.

PYQ 109 — Basidia

Exam: AIPMT 2011

Basidiospores are produced on:

A. Asci
B. Basidia
C. Sporangia
D. Conidiophores

Answer: B. Basidia

Explanation: Basidiomycetes produce their sexual spores, basidiospores, externally on basidia.

PYQ 110 — Mushroom

Exam: AIPMT 2011

Which of the following is a basidiomycete?

A. Agaricus
B. Rhizopus
C. Saccharomyces
D. Aspergillus

Answer: A. Agaricus

Explanation: Agaricus, the common mushroom, belongs to Basidiomycetes.

PYQ 111 — Sac Fungi

Exam: AIPMT 2011

Ascomycetes are commonly called:

A. Club fungi
B. Sac fungi
C. Imperfect fungi
D. Slime fungi

Answer: B. Sac fungi

Explanation: Ascomycetes are called sac fungi because their sexual spores are formed inside sac-like asci.

PYQ 112 — Club Fungi

Exam: AIPMT 2011

Basidiomycetes are commonly called:

A. Sac fungi
B. Club fungi
C. Imperfect fungi
D. Slime moulds

Answer: B. Club fungi

Explanation: Basidiomycetes are known as club fungi because their reproductive structures, basidia, are typically club-shaped.

PYQ 113 — Imperfect Fungi

Exam: AIPMT 2011

The traditional group called “fungi imperfecti” corresponds to:

A. Phycomycetes
B. Ascomycetes
C. Basidiomycetes
D. Deuteromycetes

Answer: D. Deuteromycetes

Explanation: Deuteromycetes were traditionally called imperfect fungi because their sexual reproductive stage was not known.

PYQ 114 — Lichen

Exam: AIPMT 2011

The algal component of a lichen is called:

A. Mycobiont
B. Phycobiont
C. Basidiobiont
D. Sporobiont

Answer: B. Phycobiont

Explanation: In a lichen:

Phycobiont → algal partner

Mycobiont → fungal partner

PYQ 115 — Lichen

Exam: AIPMT 2011

The fungal component of a lichen is called:

A. Phycobiont
B. Mycobiont
C. Cyanobiont
D. Photobiont

Answer: B. Mycobiont

Explanation: The fungal partner of a lichen is the mycobiont, while the photosynthetic partner is the phycobiont.

VIRUSES, VIROIDS AND PRIONS

PYQ 116 — Viral Nature

Exam: AIPMT 2010

Viruses can reproduce:

A. Independently in the soil
B. Only inside living host cells
C. Independently in water
D. Only inside dead cells

Answer: B. Only inside living host cells

Explanation: Viruses are obligate intracellular parasites and require a suitable living host cell for replication.

PYQ 117 — Virus Crystallisation

Exam: AIPMT 2010

Which characteristic of viruses supports their non-cellular nature?

A. They can be crystallised
B. They contain ribosomes
C. They possess mitochondria
D. They have cytoplasm

Answer: A. They can be crystallised

Explanation: Viruses can exist in a crystalline state outside a host, which is one reason they are considered to occupy a distinctive position between living and non-living systems.

PYQ 118 — Capsid

Exam: AIPMT 2010

The protein coat of a virus is called:

A. Capsid
B. Capsule
C. Cell wall
D. Pellicle

Answer: A. Capsid

Explanation: The viral nucleic acid is enclosed within a protein coat called the capsid, which consists of capsomeres.

PYQ 119 — Bacteriophage

Exam: AIPMT 2010

A virus that attacks bacteria is called:

A. Viroid
B. Bacteriophage
C. Prion
D. Mycoplasma

Answer: B. Bacteriophage

Explanation: Bacteriophages are viruses that infect bacteria.

PYQ 120 — Viroid

Exam: AIPMT 2010

A viroid consists of:

A. DNA and protein
B. RNA and protein
C. Naked RNA
D. Naked DNA

Answer: C. Naked RNA

Explanation: Viroids are small infectious circular RNA molecules without a protein coat.

PYQ 121 — Prion

Exam: AIPMT 2010

Which infectious agent consists primarily of protein?

A. Viroid
B. Virus
C. Prion
D. Bacteriophage

Answer: C. Prion

Explanation: Prions are infectious proteins and are associated with several transmissible neurodegenerative diseases.

PYQ 122 — Five Kingdoms

Exam: AIPMT 2010

Which sequence correctly represents the five kingdoms of Whittaker?

A. Monera, Protista, Fungi, Plantae, Animalia
B. Monera, Fungi, Plantae, Animalia, Protista
C. Protista, Monera, Fungi, Animalia, Plantae
D. Monera, Plantae, Protista, Fungi, Animalia

Answer: A

Explanation: Whittaker’s five kingdoms are:

Monera → Protista → Fungi → Plantae → Animalia

PYQ 123 — Classification Criteria

Exam: AIPMT 2010

Which combination contains important criteria used in five-kingdom classification?

A. Cell structure, body organisation and nutrition
B. Only habitat
C. Only colour and size
D. Only locomotion

Answer: A

Explanation: Whittaker considered cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships.

REPEATED — Asked 2 Times
Mycoplasma lacks a cell wall.
Exams: NEET 2017, NEET 2020

and where applicable:

REPEATED — Asked 3+ Times
Viroid = naked infectious RNA.
Exams: multiple AIPMT/NEET papers.

FINAL HIGH-YIELD REVISION TABLE

Topic	Must Remember
Five-kingdom classification	R.H. Whittaker, 1969
Monera	Prokaryotic
Archaebacteria	Extreme environments
Halophiles	High salt
Thermoacidophiles	High temperature + acidic conditions
Methanogens	Methane + anaerobic conditions
Cyanobacteria	Photosynthetic prokaryotes
Heterocyst	Nitrogen fixation
Mycoplasma	No cell wall
Diatoms	Silica wall
Dinoflagellates	Red tide
Euglena	Pellicle + mixotrophic
Slime mould	Saprophytic + plasmodium
Amoeba	Pseudopodia
Paramecium	Cilia
Trypanosoma	Flagellum
Plasmodium	Sporozoan
Fungi	Chitinous wall
Hyphae	Fungal filaments
Mycelium	Network of hyphae
Ascomycetes	Ascospores in asci
Basidiomycetes	Basidiospores on basidia
Deuteromycetes	Imperfect fungi
Rhizopus	Bread mould
Agaricus	Mushroom
Ustilago	Smut
Puccinia	Rust
Lichen	Alga + fungus
Phycobiont	Algal partner
Mycobiont	Fungal partner
Mycorrhiza	Fungus + plant root
Virus	Acellular infectious entity
Capsid	Viral protein coat
Bacteriophage	Virus of bacteria
Viroid	Naked RNA
Prion	Infectious protein

MCQ 124

Which of the following organisms is correctly associated with the kingdom Monera?

A. Amoeba
B. Nostoc
C. Paramecium
D. Euglena

Answer: B. Nostoc

Explanation: Nostoc is a cyanobacterium and therefore belongs to the prokaryotic group traditionally placed under Kingdom Monera.

MCQ 125

Which structure is primarily responsible for the slimy sheath surrounding many cyanobacteria?

A. Chitin
B. Cellulose
C. Mucilaginous sheath
D. Silica

Answer: C. Mucilaginous sheath

Explanation: Many cyanobacteria possess a mucilaginous sheath outside the cell wall. It provides protection and helps in colony formation.

MCQ 126

Which of the following is a characteristic feature of archaebacteria?

A. Cell wall always made of cellulose
B. Ability to survive in extreme habitats
C. Presence of a true nucleus
D. Absence of plasma membrane

Answer: B. Ability to survive in extreme habitats

Explanation: Archaebacteria are adapted to extreme environments such as high salt concentration, high temperature and highly acidic conditions.

MCQ 127

Which group of archaebacteria is commonly found in highly saline environments?

A. Methanogens
B. Halophiles
C. Thermoacidophiles
D. Cyanobacteria

Answer: B. Halophiles

Explanation: Halophiles are salt-loving archaebacteria that occur in environments having very high salt concentrations.

MCQ 128

Methanogenic archaebacteria are commonly associated with the production of:

A. Oxygen
B. Methane
C. Nitrogen
D. Hydrogen peroxide

Answer: B. Methane

Explanation: Methanogens produce methane as a metabolic product and are commonly found in anaerobic environments such as the rumen of cattle and anaerobic sludge.

MCQ 129

Which of the following organisms is particularly important in the rumen of cattle?

A. Methanogens
B. Dinoflagellates
C. Diatoms
D. Slime moulds

Answer: A. Methanogens

Explanation: Methanogenic archaebacteria occur in the rumen of cattle and other ruminants, where they contribute to methane production.

MCQ 130

The absence of a true nucleus in bacteria means that their genetic material is located in the:

A. Nucleolus
B. Nucleoid
C. Centrosome
D. Lysosome

Answer: B. Nucleoid

Explanation: Bacteria lack a membrane-bound nucleus. Their main chromosomal DNA occurs in a region called the nucleoid.

MCQ 131

Which of the following is NOT a membrane-bound organelle?

A. Mitochondrion
B. Golgi apparatus
C. Ribosome
D. Endoplasmic reticulum

Answer: C. Ribosome

Explanation: Ribosomes are non-membranous structures. Prokaryotic cells possess 70S ribosomes, while eukaryotic cytoplasm generally contains 80S ribosomes.

MCQ 132

The bacterial flagellum is primarily concerned with:

A. Photosynthesis
B. Locomotion
C. Protein synthesis
D. DNA replication

Answer: B. Locomotion

Explanation: Flagella provide motility to many bacteria by rotating and propelling the cell through its environment.

MCQ 133

Fimbriae in bacteria are primarily involved in:

A. Attachment to surfaces
B. ATP synthesis
C. Photosynthesis
D. Formation of endospores

Answer: A. Attachment to surfaces

Explanation: Fimbriae are short, hair-like structures that help bacteria attach to surfaces or host cells.

MCQ 134

Which bacterial structure is particularly associated with conjugation?

A. Sex pilus
B. Capsule
C. Mesosome
D. Endospore

Answer: A. Sex pilus

Explanation: Sex pili participate in bacterial conjugation by facilitating contact between bacterial cells and transfer of genetic material.

MCQ 135

Which of the following is a photosynthetic prokaryote?

A. Chlorella
B. Nostoc
C. Agaricus
D. Amoeba

Answer: B. Nostoc

Explanation: Nostoc is a cyanobacterium. Cyanobacteria are photosynthetic prokaryotes.

MCQ 136

Which cyanobacterial structure is specialized for nitrogen fixation?

A. Zoospore
B. Heterocyst
C. Conidium
D. Basidium

Answer: B. Heterocyst

Explanation: Heterocysts are specialized cells in certain cyanobacteria such as Nostoc and Anabaena and are associated with nitrogen fixation.

MCQ 137

Which of the following is a characteristic feature of diatoms?

A. Chitinous cell wall
B. Siliceous cell wall
C. Cellulose-only wall
D. Protein-only wall

Answer: B. Siliceous cell wall

Explanation: Diatom cell walls contain silica and form intricately sculptured structures known as frustules.

MCQ 138

The accumulated deposits of diatom shells are commercially useful as:

A. Diatomaceous earth
B. Peat
C. Humus
D. Coal

Answer: A. Diatomaceous earth

Explanation: Deposits of diatom shells form diatomaceous earth, which has several commercial applications, including filtration and polishing.

MCQ 139

Which group of protists is mainly characterized by the presence of a protein-rich pellicle?

A. Euglenoids
B. Diatoms
C. Slime moulds
D. Sporozoans

Answer: A. Euglenoids

Explanation: Euglenoids possess a flexible protein-rich pellicle instead of a typical rigid cell wall.

MCQ 140

The flexible body covering of Euglena is called:

A. Frustule
B. Pellicle
C. Capsule
D. Mycelium

Answer: B. Pellicle

Explanation: Euglena possesses a protein-rich pellicle that provides flexibility to the cell.

MCQ 141

Which characteristic enables Euglena to exhibit both autotrophic and heterotrophic modes of nutrition?

A. Presence of chitin
B. Mixotrophic nutrition
C. Absence of chloroplasts
D. Formation of basidia

Answer: B. Mixotrophic nutrition

Explanation: Euglena can perform photosynthesis in the presence of light and can obtain food heterotrophically under suitable conditions.

MCQ 142

Red tides are commonly associated with the rapid multiplication of:

A. Dinoflagellates
B. Diatoms
C. Cyanobacteria only
D. Slime moulds

Answer: A. Dinoflagellates

Explanation: Certain dinoflagellates multiply rapidly and may cause red tides. Some species release toxins that can harm marine organisms.

MCQ 143

Which of the following is a characteristic of dinoflagellates?

A. Silica wall in all species
B. Two flagella in many forms
C. Chitinous hyphae
D. Absence of pigments

Answer: B. Two flagella in many forms

Explanation: Dinoflagellates generally have two flagella, one longitudinal and another transverse, located in grooves of the cell.

MCQ 144

Slime moulds are generally:

A. Photosynthetic prokaryotes
B. Saprophytic protists
C. Multicellular fungi with chitinous walls throughout their life
D. Photosynthetic plants

Answer: B. Saprophytic protists

Explanation: Slime moulds are heterotrophic, saprophytic organisms traditionally included in Protista.

MCQ 145

Under suitable conditions, the vegetative phase of a slime mould may form a multinucleate structure called:

A. Plasmodium
B. Basidium
C. Ascocarp
D. Sporangium

Answer: A. Plasmodium

Explanation: The vegetative phase of plasmodial slime moulds is a multinucleate mass called plasmodium.

MCQ 146

Which protozoan group moves primarily by pseudopodia?

A. Amoeboid protozoans
B. Ciliated protozoans
C. Flagellated protozoans
D. Sporozoans

Answer: A. Amoeboid protozoans

Explanation: Amoeboid protozoans move and capture food using temporary cytoplasmic projections called pseudopodia.

MCQ 147

Paramecium belongs to which group of protozoans?

A. Amoeboid
B. Flagellated
C. Ciliated
D. Sporozoan

Answer: C. Ciliated

Explanation: Paramecium possesses numerous cilia that help in locomotion and movement of food particles.

MCQ 148

Which protozoan group is characterized by the absence of locomotory organelles in their adult forms?

A. Amoeboid protozoans
B. Flagellated protozoans
C. Ciliated protozoans
D. Sporozoans

Answer: D. Sporozoans

Explanation: Sporozoans generally lack specialized locomotory structures in their adult stages. Plasmodium is a well-known example.

MCQ 149

Which of the following is an example of a flagellated protozoan?

A. Trypanosoma
B. Paramecium
C. Amoeba
D. Plasmodium

Answer: A. Trypanosoma

Explanation: Trypanosoma is a flagellated protozoan possessing a flagellum for locomotion.

MCQ 150

The vegetative body of a typical fungus is called:

A. Thallus
B. Mycelium
C. Protonema
D. Prothallus

Answer: B. Mycelium

Explanation: The fungal body generally consists of a network of thread-like structures called hyphae. The interconnected mass of hyphae is called mycelium.

MCQ 151

A single thread-like structure of a fungus is called:

A. Hypha
B. Conidium
C. Basidium
D. Ascospore

Answer: A. Hypha

Explanation: Hyphae are the long, thread-like structures that collectively form the mycelium of a fungus.

MCQ 152

Hyphae that lack septa are called:

A. Septate hyphae
B. Aseptate or coenocytic hyphae
C. Flagellated hyphae
D. Ciliated hyphae

Answer: B. Aseptate or coenocytic hyphae

Explanation: Some fungi have continuous hyphae without septa. Such hyphae are described as aseptate or coenocytic.

MCQ 153

Which type of nutrition is characteristic of fungi?

A. Holozoic
B. Absorptive heterotrophic
C. Photoautotrophic only
D. Chemosynthetic only

Answer: B. Absorptive heterotrophic

Explanation: Fungi secrete digestive enzymes onto the substrate and absorb the resulting soluble nutrients.

CQ 154

Which substance is characteristically present in the fungal cell wall?

A. Chitin
B. Peptidoglycan only
C. Silica
D. Lignin only

Answer: A. Chitin

Explanation: Chitin is a major structural component of fungal cell walls.

MCQ 155

A fungus obtaining nutrients from dead organic matter is described as:

A. Autotrophic
B. Saprophytic
C. Holozoic
D. Photoheterotrophic

Answer: B. Saprophytic

Explanation: Saprophytic fungi obtain nutrients by decomposing and absorbing organic matter from dead organisms and organic remains.

MCQ 156

Which fungal reproductive structure produces conidia?

A. Conidiophore
B. Basidium
C. Ascogonium only
D. Rhizoid

Answer: A. Conidiophore

Explanation: Conidia are asexual spores formed externally on specialized hyphae called conidiophores.

MCQ 157

Asexual spores produced inside a sporangium are generally called:

A. Conidia
B. Sporangiospores
C. Basidiospores
D. Ascospores

Answer: B. Sporangiospores

Explanation: In fungi such as Rhizopus, asexual spores are produced within a sac-like structure called a sporangium and are called sporangiospores.

MCQ 158

Which reproductive spores are characteristic of Ascomycetes?

A. Basidiospores
B. Ascospores
C. Conidia only
D. Zoospores only

Answer: B. Ascospores

Explanation: Ascomycetes produce sexual spores called ascospores inside sac-like structures called asci.

MCQ 159

Which structure bears basidiospores?

A. Ascogonium
B. Basidium
C. Sporangium
D. Conidiophore

Answer: B. Basidium

Explanation: Basidiomycetes produce their sexual spores, called basidiospores, externally on basidia.

MCQ 160

Which of the following is correctly matched?

A. Ascomycetes — Basidiospores
B. Basidiomycetes — Ascospores
C. Ascomycetes — Ascospores
D. Deuteromycetes — Basidiospores

Answer: C. Ascomycetes — Ascospores

Explanation: Ascomycetes produce ascospores within asci, whereas basidiomycetes produce basidiospores on basidia.

MCQ 161

In fungal sexual reproduction, fusion of cytoplasm is known as:

A. Karyogamy
B. Plasmogamy
C. Meiosis
D. Budding

Answer: B. Plasmogamy

Explanation: Plasmogamy is the fusion of the cytoplasm of two compatible fungal cells.

MCQ 162

Fusion of two compatible nuclei during fungal sexual reproduction is called:

A. Plasmogamy
B. Karyogamy
C. Sporulation
D. Fragmentation

Answer: B. Karyogamy

Explanation: Karyogamy refers specifically to the fusion of two nuclei following plasmogamy.

MCQ 163

The dikaryotic condition in fungi is represented by:

A. n
B. 2n
C. n + n
D. 3n

Answer: C. n + n

Explanation: A dikaryotic cell contains two genetically distinct haploid nuclei, represented as n + n.

MCQ 164

Which sequence correctly represents major events in fungal sexual reproduction?

A. Karyogamy → plasmogamy → meiosis
B. Plasmogamy → karyogamy → meiosis
C. Meiosis → plasmogamy → karyogamy
D. Budding → meiosis → plasmogamy

Answer: B. Plasmogamy → karyogamy → meiosis

Explanation: In the generalized fungal sexual cycle, plasmogamy is followed by karyogamy, and meiosis occurs subsequently to restore the haploid condition.

MCQ 165

Which organism represents a symbiotic association between a fungus and an alga/cyanobacterium?

A. Lichen
B. Rhizopus
C. Agaricus
D. Puccinia

Answer: A. Lichen

Explanation: A lichen is a mutualistic association between a fungus and a photosynthetic partner, usually an alga or cyanobacterium.

MCQ 166

In a lichen, the photosynthetic partner is commonly called:

A. Mycobiont
B. Phycobiont
C. Sporophyte
D. Basidiobiont

Answer: B. Phycobiont

Explanation: The algal/photosynthetic component of a lichen is called the phycobiont, while the fungal component is called the mycobiont.

MCQ 167

The fungal partner in a lichen is called:

A. Phycobiont
B. Mycobiont
C. Photobiont only
D. Cyanobiont

Answer: B. Mycobiont

Explanation: The fungus forms the mycobiont and provides structural support, minerals and water to the association.

MCQ 168

Lichens are considered good indicators of:

A. Water hardness
B. Air pollution
C. Soil salinity only
D. Radioactivity only

Answer: B. Air pollution

Explanation: Lichens are sensitive to atmospheric pollutants, particularly sulphur dioxide, and therefore are useful bioindicators of air pollution.

MCQ 169

Mycorrhiza represents an association between:

A. Fungus and roots
B. Alga and roots
C. Bacterium and leaves
D. Fungus and flowers

Answer: A. Fungus and roots

Explanation: Mycorrhiza is a symbiotic association between fungal hyphae and plant roots. The fungus helps in nutrient and water absorption, while it receives organic nutrients from the plant.

MCQ 170

Which statement about viruses is correct?

A. They possess both DNA and RNA as genetic material simultaneously
B. They are cellular organisms
C. They contain either DNA or RNA as genetic material
D. They possess independent cellular metabolism

Answer: C. They contain either DNA or RNA as genetic material

Explanation: Viruses are acellular infectious entities containing either DNA or RNA as genetic material enclosed by a protein coat.

MCQ 171

The protein coat surrounding the genetic material of a virus is called:

A. Capsule
B. Capsid
C. Cell wall
D. Envelope in every virus

Answer: B. Capsid

Explanation: The viral genome is enclosed within a protein coat called the capsid. The capsid is composed of protein subunits called capsomeres.

MCQ 172

The individual protein subunits forming a viral capsid are called:

A. Capsomeres
B. Ribomeres
C. Peptomeres
D. Basidiospores

Answer: A. Capsomeres

Explanation: Capsomeres are the structural protein units that assemble to form the viral capsid.

MCQ 173

Which of the following is an example of a bacteriophage?

A. Virus infecting bacteria
B. Virus infecting only fungi
C. Bacterium infecting viruses
D. Fungus infecting bacteria

Answer: A. Virus infecting bacteria

Explanation: Bacteriophages, or phages, are viruses that infect bacterial cells.

MCQ 174

Which of the following is NOT a cellular organism?

A. Bacterium
B. Amoeba
C. Virus
D. Fungus

Answer: C. Virus

Explanation: Viruses are acellular entities. They do not possess the complete cellular organization found in bacteria, protists, fungi, plants or animals.

MCQ 175

Viroids differ from viruses mainly because viroids consist of:

A. DNA surrounded by capsid
B. Naked RNA without a protein coat
C. Protein without nucleic acid
D. RNA surrounded by a lipid envelope

Answer: B. Naked RNA without a protein coat

Explanation: Viroids are much smaller infectious agents consisting of small circular RNA molecules without a protein coat.

MCQ 176

Prions are primarily composed of:

A. DNA
B. RNA
C. Infectious protein
D. Lipid

Answer: C. Infectious protein

Explanation: Prions are infectious proteinaceous particles associated with certain neurodegenerative diseases.

MCQ 177

Which one represents an acellular infectious agent composed primarily of protein?

A. Viroid
B. Prion
C. Bacteriophage
D. Cyanobacterium

Answer: B. Prion

Explanation: Prions are infectious proteins and do not contain a nucleic acid genome like viruses and viroids.

MCQ 178

Which characteristic most clearly separates prokaryotes from eukaryotes?

A. Presence of DNA
B. Presence of ribosomes
C. Absence of a membrane-bound nucleus
D. Presence of cytoplasm

Answer: C. Absence of a membrane-bound nucleus

Explanation: Prokaryotic cells lack a membrane-bound nucleus, whereas eukaryotic cells possess a true nucleus enclosed by a nuclear membrane.

MCQ 179

Which of the following combinations represents only prokaryotic organisms?

A. Bacteria and cyanobacteria
B. Fungi and bacteria
C. Protists and cyanobacteria
D. Plants and archaebacteria

Answer: A. Bacteria and cyanobacteria

Explanation: Both bacteria and cyanobacteria are prokaryotic organisms.

MCQ 180

Which statement about the five-kingdom classification is correct?

A. It completely ignores cell structure
B. It recognizes Monera as a separate kingdom
C. It places bacteria under Plantae
D. It recognizes viruses as a sixth kingdom

Answer: B. It recognizes Monera as a separate kingdom

Explanation: Whittaker’s five-kingdom system separated prokaryotic organisms into Kingdom Monera and divided eukaryotic organisms among Protista, Fungi, Plantae and Animalia.

MCQ 181

Which kingdom includes organisms that are exclusively prokaryotic?

A. Protista
B. Monera
C. Fungi
D. Plantae

Answer: B. Monera

Explanation: In Whittaker’s five-kingdom classification, Monera consists of prokaryotic organisms.

MCQ 182

Which of the following is a major criterion used by Whittaker for classification?

A. Body colour
B. Cell structure
C. Habitat alone
D. Body size only

Answer: B. Cell structure

Explanation: Whittaker considered cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships.

MCQ 183

Which kingdom primarily contains unicellular eukaryotic organisms?

A. Monera
B. Protista
C. Plantae
D. Animalia

Answer: B. Protista

Explanation: Protista traditionally includes predominantly unicellular eukaryotic organisms.

MCQ 184

Which of the following is NOT a characteristic of Kingdom Protista?

A. Eukaryotic organization
B. Mostly unicellular forms
C. Membrane-bound nucleus
D. All members are multicellular

Answer: D. All members are multicellular

Explanation: Protists are predominantly unicellular, although some colonial or simple multicellular forms occur.

MCQ 185

Which of the following groups contains organisms with both autotrophic and heterotrophic members?

A. Protista
B. Animalia only
C. Fungi only
D. Monera only

Answer: A. Protista

Explanation: Protista includes photosynthetic forms such as many algae as well as heterotrophic forms such as protozoans.

MCQ 186

Which protists possess a silica-impregnated cell wall?

A. Euglenoids
B. Diatoms
C. Slime moulds
D. Amoeboid protozoans

Answer: B. Diatoms

Explanation: Diatoms possess cell walls containing silica, forming their characteristic frustules.

MCQ 187

The two overlapping halves of a diatom frustule are comparable to:

A. Two leaves
B. A soap box
C. Two nuclei
D. Two flagella

Answer: B. A soap box

Explanation: The diatom cell wall consists of two overlapping halves, resembling the arrangement of a soap box.

MCQ 188

Diatoms are important components of:

A. Desert vegetation
B. Phytoplankton
C. Soil fauna
D. Fungal mycelium

Answer: B. Phytoplankton

Explanation: Diatoms are major photosynthetic organisms in aquatic ecosystems and form an important component of phytoplankton.

MCQ 189

Which organisms are among the major producers in aquatic ecosystems?

A. Diatoms
B. Tapeworms
C. Fungi
D. Protozoan parasites only

Answer: A. Diatoms

Explanation: Diatoms are photosynthetic and contribute significantly to primary production in aquatic ecosystems.

MCQ 190

Which group of protists contains organisms that may have cellulose plates on their cell surface?

A. Dinoflagellates
B. Euglenoids
C. Amoebae
D. Sporozoans

Answer: A. Dinoflagellates

Explanation: Many dinoflagellates have a stiff cell wall made of cellulose plates.

MCQ 191

The body of many dinoflagellates is generally:

A. Without pigments
B. Covered by cellulose plates
C. Made of chitinous hyphae
D. Surrounded by silica frustules

Answer: B. Covered by cellulose plates

Explanation: Many dinoflagellates have a cell wall composed of cellulose plates arranged in characteristic patterns.

MCQ 192

Which pigment combination is commonly responsible for the characteristic colour of many dinoflagellates?

A. Chlorophyll only
B. Various carotenoid pigments along with chlorophyll
C. Haemoglobin
D. Melanin only

Answer: B. Various carotenoid pigments along with chlorophyll

Explanation: Dinoflagellates possess chlorophyll and various accessory pigments, which may give them distinctive colours.

MCQ 193

Which protist is known for its ability to survive in nutrient-poor environments by changing its mode of nutrition?

A. Euglena
B. Agaricus
C. Rhizopus
D. Nostoc

Answer: A. Euglena

Explanation: Euglenoids can photosynthesize when light is available and may obtain nutrients heterotrophically under suitable conditions.

MCQ 194

Which of the following is characteristic of euglenoids rather than diatoms?

A. Pellicle
B. Silica wall
C. Frustule
D. Diatomaceous deposits

Answer: A. Pellicle

Explanation: Euglenoids possess a flexible protein-rich pellicle, whereas diatoms possess a silica-containing frustule.

MCQ 195

Which group of organisms has a plasmodial stage during its life cycle?

A. Slime moulds
B. Diatoms
C. Dinoflagellates
D. Cyanobacteria

Answer: A. Slime moulds

Explanation: Plasmodial slime moulds form a multinucleate, creeping plasmodium during their vegetative phase.

MCQ 196

Slime moulds generally feed on:

A. Dead organic matter
B. Atmospheric nitrogen only
C. Sunlight directly
D. Inorganic salts only

Answer: A. Dead organic matter

Explanation: Slime moulds are saprophytic and obtain nutrients from decaying organic material.

MCQ 197

Under unfavourable conditions, slime moulds may form:

A. Fruiting bodies
B. Basidia only
C. Root nodules
D. Heterocysts

Answer: A. Fruiting bodies

Explanation: During unfavourable conditions, slime moulds form fruiting structures bearing spores.

MCQ 198

Which of the following protozoans is associated with malaria?

A. Trypanosoma
B. Plasmodium
C. Paramecium
D. Amoeba

Answer: B. Plasmodium

Explanation: Plasmodium is a sporozoan protozoan responsible for malaria.

MCQ 199

Trypanosoma is classified among:

A. Amoeboid protozoans
B. Flagellated protozoans
C. Ciliated protozoans
D. Sporozoans

Answer: B. Flagellated protozoans

Explanation: Trypanosoma possesses a flagellum and belongs to the flagellated protozoans.

MCQ 200

Which organism is commonly used as an example of a ciliated protozoan?

A. Paramecium
B. Trypanosoma
C. Plasmodium
D. Entamoeba

Answer: A. Paramecium

Explanation: Paramecium moves with the help of numerous cilia.

MCQ 201

Which protozoan group commonly includes Amoeba-like organisms?

A. Amoeboid protozoans
B. Flagellated protozoans
C. Ciliated protozoans
D. Sporozoans

Answer: A. Amoeboid protozoans

Explanation: Amoeboid protozoans move using pseudopodia.

MCQ 202

Which of the following is a defining characteristic of fungi?

A. They are generally absorptive heterotrophs
B. They always perform photosynthesis
C. They lack a cell wall
D. They contain chlorophyll in all cells

Answer: A. They are generally absorptive heterotrophs

Explanation: Fungi obtain nutrients by secreting enzymes and absorbing dissolved organic substances.

MCQ 203

The fungal cell wall differs from the bacterial cell wall because the fungal wall characteristically contains:

A. Chitin
B. Peptidoglycan
C. Silica
D. Lignin

Answer: A. Chitin

Explanation: Chitin is a characteristic structural component of fungal cell walls.

MCQ 204

Which fungal form consists of a single-celled body?

A. Yeast
B. Mushroom
C. Rhizopus mycelium
D. Agaricus fruiting body

Answer: A. Yeast

Explanation: Yeasts are generally unicellular fungi, although some may form pseudohyphae under certain conditions.

MCQ 205

Which mode of reproduction is commonly associated with yeast?

A. Budding
B. Binary fission only
C. Fragmentation of basidia
D. Heterocyst formation

Answer: A. Budding

Explanation: Yeast commonly reproduces asexually by budding.

MCQ 206

Which of the following is an asexual method of reproduction in fungi?

A. Fragmentation
B. Karyogamy
C. Plasmogamy
D. Syngamy

Answer: A. Fragmentation

Explanation: Fungi can reproduce asexually through fragmentation, budding or formation of asexual spores.

MCQ 207

Which structure in fungi is primarily involved in absorption of nutrients?

A. Hyphae
B. Basidia only
C. Ascospores
D. Capsomeres

Answer: A. Hyphae

Explanation: The extensive hyphal network increases surface area for secretion of digestive enzymes and absorption of nutrients.

MCQ 208

Which fungal group is traditionally associated with bread mould Rhizopus?

A. Phycomycetes
B. Ascomycetes
C. Basidiomycetes
D. Deuteromycetes

Answer: A. Phycomycetes

Explanation: In the traditional NCERT classification, Rhizopus is included under Phycomycetes.

MCQ 209

Which organism is a common example of a mushroom?

A. Agaricus
B. Nostoc
C. Euglena
D. Plasmodium

Answer: A. Agaricus

Explanation: Agaricus is a well-known basidiomycete commonly represented by mushroom forms.

MCQ 210

Which fungal group traditionally includes rust fungi?

A. Basidiomycetes
B. Phycomycetes
C. Deuteromycetes
D. Euglenoids

Answer: A. Basidiomycetes

Explanation: Rust fungi such as Puccinia are traditionally classified under Basidiomycetes in the NCERT treatment.

MCQ 211

Puccinia is commonly known as:

A. Rust fungus
B. Bread mould
C. Mushroom
D. Yeast

Answer: A. Rust fungus

Explanation: Puccinia is a parasitic fungus associated with rust diseases of plants.

MCQ 212

Ustilago is associated with:

A. Smut disease
B. Malaria
C. Red tide
D. Ringworm only

Answer: A. Smut disease

Explanation: Ustilago species are traditionally recognized as smut fungi and cause smut diseases in plants.

MCQ 213

Which fungal group was traditionally called “fungi imperfecti”?

A. Ascomycetes
B. Basidiomycetes
C. Deuteromycetes
D. Phycomycetes

Answer: C. Deuteromycetes

Explanation: Deuteromycetes were traditionally called imperfect fungi because only their asexual or imperfect stage was known.

MCQ 214

The absence of a known sexual stage was historically the basis for placing fungi in:

A. Deuteromycetes
B. Basidiomycetes
C. Ascomycetes
D. Phycomycetes

Answer: A. Deuteromycetes

Explanation: Deuteromycetes was a traditional artificial group for fungi in which the sexual reproductive stage had not been observed.

MCQ 215

Which fungal reproductive structure contains asci?

A. Ascocarp
B. Basidiocarp
C. Sporangium
D. Conidiophore

Answer: A. Ascocarp

Explanation: In many ascomycetes, asci are contained within a fruiting body called an ascocarp.

MCQ 216

A fruiting body containing basidia is called:

A. Basidiocarp
B. Ascocarp
C. Sporangium
D. Conidium

Answer: A. Basidiocarp

Explanation: Basidiocarps are fruiting bodies of basidiomycetes that bear basidia.

MCQ 217

Which reproductive structure is characteristic of Basidiomycetes?

A. Basidium
B. Ascus
C. Sporangium only
D. Heterocyst

Answer: A. Basidium

Explanation: Basidia are specialized structures on which basidiospores are produced.

MCQ 218

Which structure is associated with the production of ascospores?

A. Ascus
B. Basidium
C. Heterocyst
D. Conidiophore

Answer: A. Ascus

Explanation: Ascospores are produced within sac-like structures called asci.

MCQ 219

Which of the following is NOT a fungal reproductive structure?

A. Ascus
B. Basidium
C. Conidiophore
D. Heterocyst

Answer: D. Heterocyst

Explanation: Heterocysts occur in certain cyanobacteria and are associated with nitrogen fixation, not fungal reproduction.

MCQ 220

Which fungal group is traditionally represented by both Rhizopus and Mucor?

A. Phycomycetes
B. Basidiomycetes
C. Deuteromycetes
D. Ascomycetes

Answer: A. Phycomycetes

Explanation: Rhizopus and Mucor are traditionally included in Phycomycetes in the NCERT classification.

MCQ 221

Which of the following is a symbiotic association involving a fungus and a photosynthetic organism?

A. Lichen
B. Plasmodium
C. Paramecium
D. Mycoplasma

Answer: A. Lichen

Explanation: Lichens consist of a fungal component and a photosynthetic partner.

MCQ 222

Which component of a lichen is primarily responsible for photosynthesis?

A. Mycobiont
B. Phycobiont
C. Fungal hyphae
D. Basidium

Answer: B. Phycobiont

Explanation: The photosynthetic algal or cyanobacterial partner is the phycobiont.

MCQ 223

Which component of a lichen provides the structural framework?

A. Phycobiont
B. Mycobiont
C. Chloroplast
D. Heterocyst

Answer: B. Mycobiont

Explanation: The fungal component forms the major structural framework of the lichen.

MCQ 224

Which of the following organisms is associated with mycorrhiza?

A. Fungus and plant roots
B. Fungus and animal skin
C. Alga and protozoan
D. Bacterium and virus

Answer: A. Fungus and plant roots

Explanation: Mycorrhiza is the symbiotic association of fungal hyphae with plant roots.

MCQ 225

A major benefit of mycorrhizal association to the plant is improved absorption of:

A. Water and minerals
B. Carbon dioxide only
C. Oxygen only
D. Nitrogen gas directly in all cases

Answer: A. Water and minerals

Explanation: Fungal hyphae increase the effective absorptive area of roots and can improve uptake of water and mineral nutrients, especially phosphorus.

MCQ 226

Which of the following is NOT a characteristic of viruses?

A. Acellular organization
B. Obligatory intracellular parasitism
C. Independent cellular metabolism
D. Genetic material

Answer: C. Independent cellular metabolism

Explanation: Viruses lack independent cellular metabolism and depend on host cells for replication.

MCQ 227

Viruses can multiply only when they are:

A. Inside suitable living host cells
B. In distilled water
C. On dead organic matter
D. In soil without host cells

Answer: A. Inside suitable living host cells

Explanation: Viruses are obligate intracellular parasites and require living host cells for multiplication.

MCQ 228

Outside a suitable host, viruses generally exist as:

A. Fully independent cells
B. Inert particles
C. Bacteria
D. Protozoans

Answer: B. Inert particles

Explanation: Outside host cells, viruses can remain as inert infectious particles and do not carry out independent cellular metabolism.

MCQ 229

Which component of a virus determines much of its structural specificity?

A. Capsid proteins
B. Cellulose wall
C. Peptidoglycan
D. Chitin

Answer: A. Capsid proteins

Explanation: Viral capsid proteins form the structural shell and are specific to particular viruses.

MCQ 230

Which statement correctly describes a viral genome?

A. It is always double-stranded DNA
B. It is always RNA
C. It may be DNA or RNA depending on the virus
D. It always contains both DNA and RNA

Answer: C. It may be DNA or RNA depending on the virus

Explanation: Viruses have either DNA or RNA as their genetic material.

MCQ 231

Which of the following is associated specifically with plant viral diseases?

A. Viroids
B. Basidia
C. Heterocysts
D. Mycelium

Answer: A. Viroids

Explanation: Viroids are small infectious RNA molecules and are known to cause diseases in plants.

MCQ 232

The genetic material of a viroid is:

A. Double-stranded DNA
B. Circular RNA
C. Linear protein
D. DNA-protein complex

Answer: B. Circular RNA

Explanation: Viroids consist of small, circular, single-stranded RNA molecules without a protein coat.

MCQ 233

Which infectious agent lacks both a capsid and a cellular structure?

A. Viroid
B. Bacterium
C. Fungus
D. Protozoan

Answer: A. Viroid

Explanation: Viroids are naked infectious RNA molecules without the protein capsid characteristic of viruses.

MCQ 234

Which infectious agent is associated with diseases such as Creutzfeldt-Jakob disease?

A. Viroid
B. Prion
C. Cyanobacterium
D. Dinoflagellate

Answer: B. Prion

Explanation: Prions are infectious proteins associated with several transmissible neurodegenerative diseases.

MCQ 235

Which of the following represents the simplest type of infectious biological entity among the listed options?

A. Viroid
B. Fungus
C. Bacterium
D. Protozoan

Answer: A. Viroid

Explanation: Viroids are extremely simple infectious agents consisting essentially of a small RNA molecule without a protein coat.

MCQ 236

Which kingdom contains organisms having chitinous cell walls and absorptive heterotrophic nutrition?

A. Protista
B. Fungi
C. Plantae
D. Animalia

Answer: B. Fungi

Explanation: Fungi characteristically possess chitin-containing cell walls and obtain nutrients through absorption.

MCQ 237

Which kingdom is characterized by autotrophic or heterotrophic nutrition and includes multicellular photosynthetic organisms?

A. Plantae
B. Monera
C. Protista
D. Animalia

Answer: A. Plantae

Explanation: Kingdom Plantae primarily contains multicellular photosynthetic organisms, although the details of modern classification are more complex.

MCQ 238

Which kingdom primarily contains multicellular organisms that ingest their food?

A. Fungi
B. Animalia
C. Monera
D. Protista

Answer: B. Animalia

Explanation: Animals are multicellular eukaryotes that generally obtain nutrition by ingestion and subsequent digestion.

MCQ 239

Which feature distinguishes fungi from green plants in the traditional five-kingdom classification?

A. Fungi generally lack chlorophyll and obtain food heterotrophically
B. Fungi possess true nuclei
C. Fungi are eukaryotic
D. Fungi have cytoplasm

Answer: A. Fungi generally lack chlorophyll and obtain food heterotrophically

Explanation: Both fungi and plants are eukaryotic, but fungi generally lack chlorophyll and obtain nutrients heterotrophically by absorption.

MCQ 240

Which of the following correctly represents the five kingdoms proposed by R.H. Whittaker?

A. Monera, Protista, Fungi, Plantae, Animalia
B. Monera, Viruses, Fungi, Plantae, Animalia
C. Bacteria, Protista, Fungi, Plantae, Animalia
D. Archaea, Bacteria, Protista, Plantae, Animalia

Answer: A. Monera, Protista, Fungi, Plantae, Animalia

Explanation: Whittaker proposed the five-kingdom system consisting of Monera, Protista, Fungi, Plantae and Animalia.

MCQ 241

Which feature of archaebacterial cell membranes helps them survive under extreme environmental conditions?

A. Presence of cellulose
B. Unique membrane lipid composition
C. Presence of chitin
D. Absence of lipids

Answer: B. Unique membrane lipid composition

Explanation: Archaebacteria possess distinctive membrane lipids that contribute to their ability to tolerate extreme environmental conditions.

MCQ 242

Which type of archaebacteria is characteristically associated with hot acidic environments?

A. Halophiles
B. Methanogens
C. Thermoacidophiles
D. Cyanobacteria

Answer: C. Thermoacidophiles

Explanation: Thermoacidophiles are adapted to environments characterized by high temperatures and acidic conditions.

MCQ 243

Which of the following habitats is most suitable for halophilic archaebacteria?

A. Highly saline environments
B. Freshwater ponds only
C. Dry plant tissues
D. Human blood

Answer: A. Highly saline environments

Explanation: Halophiles are adapted to environments with very high salt concentrations, such as salt-rich lakes and saline habitats.

MCQ 244

Which bacterial form is described as spherical?

A. Bacillus
B. Coccus
C. Vibrio
D. Spirillum

Answer: B. Coccus

Explanation: Cocci are spherical or approximately spherical bacteria.

MCQ 245

Rod-shaped bacteria are generally called:

A. Cocci
B. Bacilli
C. Vibrios
D. Spirochaetes

Answer: B. Bacilli

Explanation: Bacilli are rod-shaped bacteria.

MCQ 246

Which bacterial shape resembles a comma?

A. Coccus
B. Bacillus
C. Vibrio
D. Spirillum

Answer: C. Vibrio

Explanation: Vibrios are curved, comma-shaped bacteria.

MCQ 247

Spiral-shaped bacteria are commonly referred to as:

A. Cocci
B. Bacilli
C. Vibrios
D. Spirilla

Answer: D. Spirilla

Explanation: Spirilla are spiral-shaped bacteria.

MCQ 248

Which bacterial structure provides protection against adverse environmental conditions in some bacteria?

A. Capsule
B. Ribosome
C. Nucleoid
D. Mesosome

Answer: A. Capsule

Explanation: A capsule or slime layer may protect bacterial cells from desiccation and other environmental stresses and can contribute to pathogenicity.

MCQ 249

The bacterial capsule is located:

A. Inside the nucleoid
B. Outside the cell wall
C. Inside the ribosome
D. Between DNA molecules

Answer: B. Outside the cell wall

Explanation: The capsule is an external protective covering surrounding the bacterial cell wall in encapsulated bacteria.

MCQ 250

Which of the following is NOT present as a membrane-bound organelle in a typical bacterial cell?

A. Mitochondrion
B. Ribosome
C. Plasma membrane
D. Cytoplasm

Answer: A. Mitochondrion

Explanation: Bacteria are prokaryotes and lack membrane-bound organelles such as mitochondria and Golgi bodies.

MCQ 251

Bacterial ribosomes are generally:

A. 80S
B. 70S
C. 90S
D. 60S

Answer: B. 70S

Explanation: Prokaryotic cells contain 70S ribosomes, composed of 50S and 30S subunits.

MCQ 252

The genetic material of most bacteria is generally:

A. A single circular DNA molecule
B. Multiple linear chromosomes enclosed in a nucleus
C. RNA only
D. DNA enclosed in a nuclear membrane

Answer: A. A single circular DNA molecule

Explanation: Most bacteria possess a main circular chromosome located in the nucleoid region.

MCQ 253

Small additional circular DNA molecules found in many bacteria are called:

A. Plasmids
B. Capsomeres
C. Frustules
D. Conidia

Answer: A. Plasmids

Explanation: Plasmids are small extrachromosomal DNA molecules that can replicate independently of the bacterial chromosome.

MCQ 254

Plasmids are particularly important because they may carry genes responsible for:

A. Photosynthesis in all bacteria
B. Antibiotic resistance
C. Formation of fungal spores
D. Production of chlorophyll in animals

Answer: B. Antibiotic resistance

Explanation: Some plasmids carry antibiotic-resistance genes and can be transferred between bacterial cells.

MCQ 255

Which group of organisms is commonly capable of nitrogen fixation?

A. Certain cyanobacteria
B. All fungi
C. All protozoans
D. All viruses

Answer: A. Certain cyanobacteria

Explanation: Certain cyanobacteria, including Nostoc and Anabaena, can fix atmospheric nitrogen.

MCQ 256

Which pigment enables cyanobacteria to carry out oxygenic photosynthesis along with chlorophyll a?

A. Phycobilins
B. Haemoglobin
C. Melanin
D. Keratin

Answer: A. Phycobilins

Explanation: Cyanobacteria contain accessory pigments such as phycocyanin and phycoerythrin in addition to chlorophyll a.

MCQ 257

The blue colour of many cyanobacteria is primarily associated with:

A. Phycocyanin
B. Haemoglobin
C. Xanthophyll only
D. Melanin

Answer: A. Phycocyanin

Explanation: Phycocyanin is a blue phycobilin pigment characteristic of cyanobacteria.

MCQ 258

The red pigment found in some cyanobacteria is:

A. Phycoerythrin
B. Phycocyanin
C. Chlorophyll b
D. Carotene only

Answer: A. Phycoerythrin

Explanation: Phycoerythrin is a reddish phycobilin pigment found in certain cyanobacteria and algae.

MCQ 259

Which statement about cyanobacteria is correct?

A. They are eukaryotic algae
B. They possess membrane-bound chloroplasts
C. They are photosynthetic prokaryotes
D. They lack pigments

Answer: C. They are photosynthetic prokaryotes

Explanation: Cyanobacteria are prokaryotes capable of photosynthesis but do not possess chloroplasts.

MCQ 260

Which organism is traditionally described as a photosynthetic bacterium capable of forming colonies?

A. Nostoc
B. Amoeba
C. Agaricus
D. Euglena

Answer: A. Nostoc

Explanation: Nostoc is a filamentous cyanobacterium that can form colonies and contains specialized heterocysts in nitrogen-fixing species.

MCQ 261

Which group of protists contains organisms that may possess golden-yellow pigments?

A. Chrysophytes
B. Amoeboid protozoans
C. Sporozoans
D. Slime moulds

Answer: A. Chrysophytes

Explanation: Chrysophytes include diatoms and golden algae, which possess characteristic accessory pigments.

MCQ 262

Which of the following is included under chrysophytes?

A. Diatoms
B. Paramecium
C. Plasmodium
D. Trypanosoma

Answer: A. Diatoms

Explanation: Diatoms are included among chrysophytes in the traditional NCERT treatment of Protista.

MCQ 263

Which feature of diatoms makes their remains resistant to decomposition?

A. Silica-rich cell wall
B. Chitinous cell wall
C. Protein pellicle
D. Cellulose-free cytoplasm

Answer: A. Silica-rich cell wall

Explanation: Their silica-rich frustules are highly resistant and accumulate after the organisms die.

MCQ 264

Diatomaceous deposits are particularly rich in:

A. Silica
B. Chitin
C. Peptidoglycan
D. Keratin

Answer: A. Silica

Explanation: Diatomaceous earth consists largely of accumulated silica-containing remains of diatoms.

MCQ 265

Which protists commonly possess two flagella arranged in distinct grooves?

A. Dinoflagellates
B. Amoebae
C. Slime moulds
D. Diatoms

Answer: A. Dinoflagellates

Explanation: Dinoflagellates characteristically possess two flagella, usually one transverse and one longitudinal.

MCQ 266

A dinoflagellate bloom that discolours seawater is commonly called:

A. Green tide
B. Red tide
C. Black tide
D. White tide

Answer: B. Red tide

Explanation: Rapid multiplication of certain pigmented dinoflagellates can produce red tides.

MCQ 267

Some dinoflagellates cause ecological problems because they may release:

A. Toxins
B. Chitin
C. Antibiotics in all cases
D. Cellulose fibres

Answer: A. Toxins

Explanation: Certain dinoflagellate blooms produce toxins that can affect fish and other marine organisms.

MCQ 268

Which feature allows Euglena to maintain flexibility despite lacking a rigid cellulose cell wall?

A. Pellicle
B. Frustule
C. Capsule
D. Chitin layer

Answer: A. Pellicle

Explanation: The protein-rich pellicle gives euglenoids flexibility and supports their changing body shape.

MCQ 269

Which of the following is most characteristic of euglenoids?

A. Flexible pellicle
B. Silica frustule
C. Chitinous hyphae
D. Basidiospores

Answer: A. Flexible pellicle

Explanation: Euglenoids possess a proteinaceous pellicle instead of a rigid cell wall.

MCQ 270

Which protists are commonly considered decomposers in ecosystems?

A. Slime moulds
B. Dinoflagellates
C. Diatoms
D. Euglenoids only

Answer: A. Slime moulds

Explanation: Slime moulds are saprophytic organisms and feed on decaying organic material.

MCQ 271

Which characteristic is common to members of Kingdom Fungi?

A. Absorptive heterotrophic nutrition
B. Ingestion of solid food
C. Photosynthesis in all members
D. Absence of cell walls

Answer: A. Absorptive heterotrophic nutrition

Explanation: Fungi digest food externally by enzyme secretion and absorb the soluble products.

MCQ 272

Which of the following is NOT generally present in fungal cells?

A. Chlorophyll
B. Nucleus
C. Mitochondria
D. Cell wall

Answer: A. Chlorophyll

Explanation: Fungi generally lack chlorophyll and are therefore heterotrophic.

MCQ 273

Which fungal group is traditionally associated with sac fungi?

A. Ascomycetes
B. Basidiomycetes
C. Phycomycetes
D. Deuteromycetes

Answer: A. Ascomycetes

Explanation: Ascomycetes are commonly called sac fungi because their sexual spores develop inside sac-like asci.

MCQ 274

Which fungal group is traditionally called club fungi?

A. Basidiomycetes
B. Ascomycetes
C. Phycomycetes
D. Deuteromycetes

Answer: A. Basidiomycetes

Explanation: Basidiomycetes are commonly called club fungi because basidia are club-shaped reproductive structures.

CQ 275

Which group is traditionally called sac fungi?

A. Ascomycetes
B. Basidiomycetes
C. Deuteromycetes
D. Cyanobacteria

Answer: A. Ascomycetes

Explanation: Their characteristic reproductive structure, the ascus, is sac-like and contains ascospores.

MCQ 276

Which fungal group traditionally includes many moulds with coenocytic hyphae?

A. Phycomycetes
B. Basidiomycetes
C. Deuteromycetes
D. Ascomycetes only

Answer: A. Phycomycetes

Explanation: Traditional NCERT classification places Rhizopus and related forms with aseptate/coenocytic hyphae under Phycomycetes.

MCQ 277

Which fungal reproductive process results in restoration of the haploid state?

A. Meiosis
B. Plasmogamy
C. Karyogamy
D. Budding

Answer: A. Meiosis

Explanation: Meiosis reduces the chromosome number and restores the haploid condition following the diploid stage.

MCQ 278

The fusion of compatible fungal protoplasts before nuclear fusion is called:

A. Plasmogamy
B. Karyogamy
C. Meiosis
D. Sporulation

Answer: A. Plasmogamy

Explanation: Plasmogamy is the fusion of cytoplasm of compatible cells without immediate fusion of their nuclei.

MCQ 279

The stage between plasmogamy and karyogamy in many fungi is characterized by:

A. Dikaryotic condition
B. Triploid condition
C. Complete absence of nuclei
D. Tetraploid condition

Answer: A. Dikaryotic condition

Explanation: The two haploid nuclei remain separate after plasmogamy, producing the n+n dikaryotic condition.

MCQ 280

Which structure is primarily associated with the sexual reproduction of basidiomycetes?

A. Basidium
B. Sporangium
C. Conidiophore
D. Heterocyst

Answer: A. Basidium

Explanation: Basidium is the specialized reproductive structure on which basidiospores are formed.

MCQ 281

Which structure is primarily associated with sexual reproduction in ascomycetes?

A. Ascus
B. Basidium
C. Heterocyst
D. Sporangium

Answer: A. Ascus

Explanation: Ascospores develop within asci, the characteristic sexual reproductive structures of ascomycetes.

MCQ 282

Which fungal spores are generally produced externally on basidia?

A. Basidiospores
B. Ascospores
C. Sporangiospores
D. Zygospores

Answer: A. Basidiospores

Explanation: Basidiospores are formed externally on basidia.

MCQ 283

Which spores are formed inside asci?

A. Ascospores
B. Basidiospores
C. Conidia
D. Sporangiospores

Answer: A. Ascospores

Explanation: Ascospores are produced inside sac-like asci.

MCQ 284

Which fungal reproductive structure produces spores externally rather than within a sac-like structure?

A. Basidium
B. Sporangium
C. Ascus
D. Heterocyst

Answer: A. Basidium

Explanation: Basidiospores are produced externally on basidia.

MCQ 285

Which of the following is an example of a fungal disease-causing organism traditionally included under Basidiomycetes?

A. Puccinia
B. Rhizopus
C. Mucor
D. Saccharomyces

Answer: A. Puccinia

Explanation: Puccinia is a rust fungus traditionally classified under Basidiomycetes.

MCQ 286

Which fungal organism is associated with smut disease?

A. Ustilago
B. Agaricus
C. Rhizopus
D. Penicillium

Answer: A. Ustilago

Explanation: Ustilago species are traditionally recognized as smut fungi causing diseases in plants.

MCQ 287

Which organism is a traditional example of an imperfect fungus?

A. Alternaria
B. Agaricus
C. Puccinia
D. Rhizopus

Answer: A. Alternaria

Explanation: Alternaria was traditionally placed under Deuteromycetes because its sexual reproductive stage was not known in the traditional classification.

MCQ 288

Which type of fungal spores are commonly associated with asexual reproduction in Deuteromycetes?

A. Conidia
B. Basidiospores
C. Ascospores
D. Zygospores

Answer: A. Conidia

Explanation: Deuteromycetes were characterized mainly by their known asexual reproductive stage, commonly involving conidia.

MCQ 289

Which of the following is an important characteristic of lichens?

A. They are a symbiotic association
B. They are exclusively fungi
C. They are exclusively algae
D. They are viruses

Answer: A. They are a symbiotic association

Explanation: Lichens represent a symbiotic association between a fungus and a photosynthetic partner.

MCQ 290

Which lichen partner is responsible for providing carbohydrates through photosynthesis?

A. Photosynthetic partner
B. Mycobiont
C. Fungal hyphae only
D. Basidium

Answer: A. Photosynthetic partner

Explanation: The algal or cyanobacterial partner performs photosynthesis and supplies organic nutrients to the association.

MCQ 291

Which of the following can serve as the photosynthetic partner in a lichen?

A. Cyanobacterium
B. Basidium
C. Protozoan
D. Virus

Answer: A. Cyanobacterium

Explanation: The photosynthetic partner of a lichen may be a green alga or a cyanobacterium.

MCQ 292

Which association improves the mineral and water supply to the plant through fungal hyphae?

A. Mycorrhiza
B. Lichen
C. Red tide
D. Plasmogamy

Answer: A. Mycorrhiza

Explanation: Mycorrhizal fungi extend into the soil and increase the effective absorptive surface associated with plant roots.

MCQ 293

Which statement about viruses is incorrect?

A. Viruses are acellular
B. Viruses depend on host cells for multiplication
C. Viruses possess their own complete cellular machinery
D. Viruses contain nucleic acid

Answer: C. Viruses possess their own complete cellular machinery

Explanation: Viruses lack independent cellular machinery and depend on host cells for replication.

MCQ 294

The complete infectious virus particle is called a:

A. Virion
B. Viroid
C. Prion
D. Capsomere

Answer: A. Virion

Explanation: A complete mature infectious virus particle outside the host cell is called a virion.

MCQ 295

Which term refers specifically to the protein subunit of a viral capsid?

A. Capsomere
B. Virion
C. Viroid
D. Plasmid

Answer: A. Capsomere

Explanation: Capsomeres are the individual protein units that assemble to form the capsid.

MCQ 296

A virus that specifically infects bacterial cells is called a:

A. Bacteriophage
B. Viroid
C. Mycovirus
D. Cyanophage only

Answer: A. Bacteriophage

Explanation: Bacteriophages are viruses that infect bacteria.

MCQ 297

Which of the following is a major difference between a virus and a viroid?

A. Virus contains nucleic acid; viroid does not
B. Virus generally has a protein coat; viroid lacks one
C. Viroid is always a bacterium
D. Virus is always cellular

Answer: B. Virus generally has a protein coat; viroid lacks one

Explanation: Viruses possess nucleic acid enclosed by a protein capsid, whereas viroids are naked infectious RNA molecules.

MCQ 298

Which of the following is correctly matched?

A. Viroid — infectious RNA
B. Prion — infectious DNA
C. Capsomere — bacterial chromosome
D. Plasmid — viral protein

Answer: A. Viroid — infectious RNA

Explanation: Viroids are infectious, small circular RNA molecules lacking a protein coat.

MCQ 299

Which of the following is NOT a criterion used by Whittaker in the five-kingdom classification?

A. Cell structure
B. Mode of nutrition
C. Reproductive modes
D. Colour of the organism

Answer: D. Colour of the organism

Explanation: Whittaker considered cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships—not organism colour.

MCQ 300

Which sequence correctly represents the kingdoms in Whittaker’s five-kingdom system?

A. Monera → Protista → Fungi → Plantae → Animalia
B. Monera → Fungi → Protista → Animalia → Plantae
C. Protista → Monera → Fungi → Animalia → Plantae
D. Monera → Plantae → Protista → Fungi → Animalia

Answer: A. Monera → Protista → Fungi → Plantae → Animalia

Explanation: Whittaker’s five kingdoms are Monera, Protista, Fungi, Plantae and Animalia.

MCQ 301

Which of the following organisms is best classified as a prokaryote?

A. Euglena
B. Nostoc
C. Amoeba
D. Yeast

Answer: B. Nostoc

Explanation: Nostoc is a cyanobacterium and therefore has prokaryotic cellular organization.

MCQ 302

Which cellular feature is absent in all prokaryotic organisms?

A. Plasma membrane
B. Cytoplasm
C. Membrane-bound nucleus
D. Ribosomes

Answer: C. Membrane-bound nucleus

Explanation: Prokaryotes do not possess a membrane-bound nucleus. Their DNA lies in the nucleoid region.

MCQ 303

Which of the following is characteristic of the prokaryotic cell wall?

A. It is made primarily of peptidoglycan in typical bacteria
B. It is made of chitin
C. It is made of silica
D. It is made exclusively of cellulose

Answer: A. It is made primarily of peptidoglycan in typical bacteria

Explanation: The cell wall of typical bacteria contains peptidoglycan (murein). Archaebacterial walls have a different composition.

MCQ 304

Which group differs from typical bacteria in the chemical nature of its cell wall?

A. Archaebacteria
B. Protozoans
C. Dinoflagellates
D. Basidiomycetes

Answer: A. Archaebacteria

Explanation: Archaebacteria possess distinctive cell-wall and membrane characteristics that differ from those of typical eubacteria.

MCQ 305

Which group is particularly adapted to anaerobic conditions and methane production?

A. Methanogens
B. Diatoms
C. Dinoflagellates
D. Euglenoids

Answer: A. Methanogens

Explanation: Methanogenic archaebacteria are anaerobic organisms that produce methane during their metabolism.

MCQ 306

Which of the following is most likely to contain methanogens?

A. Rumen of cattle
B. Upper atmosphere
C. Dry desert sand only
D. Human hair surface

Answer: A. Rumen of cattle

Explanation: Methanogens occur in anaerobic environments such as the rumen of ruminants.

MCQ 307

Which group of archaebacteria is adapted to extremely high salt concentrations?

A. Halophiles
B. Methanogens
C. Thermoacidophiles
D. Mycoplasma

Answer: A. Halophiles

Explanation: Halophiles are salt-loving archaebacteria adapted to highly saline environments.

MCQ 308

Which bacterial group is known for surviving without a rigid cell wall?

A. Mycoplasma
B. Nostoc
C. Bacillus
D. Rhizobium

Answer: A. Mycoplasma

Explanation: Mycoplasma lacks a cell wall and is therefore highly flexible and resistant to antibiotics that target bacterial cell-wall synthesis.

MCQ 309

The absence of a cell wall in Mycoplasma makes its shape:

A. Always spherical
B. Always rod-shaped
C. Highly variable
D. Always spiral

Answer: C. Highly variable

Explanation: Without a rigid cell wall, Mycoplasma can exhibit considerable variation in shape, a condition known as pleomorphism.

MCQ 310

Which term describes the ability of an organism such as Mycoplasma to occur in different shapes?

A. Pleomorphism
B. Plasmogamy
C. Karyogamy
D. Mixotrophy

Answer: A. Pleomorphism

Explanation: Pleomorphism means the occurrence of different forms or shapes within the same organism or species.

MCQ 311

Which bacterial structure is mainly responsible for maintaining cell shape in typical bacteria?

A. Cell wall
B. Ribosome
C. Nucleoid
D. Plasmid

Answer: A. Cell wall

Explanation: The rigid bacterial cell wall provides structural support and helps maintain cell shape.

MCQ 312

Which structure forms the selectively permeable boundary of a bacterial cell?

A. Plasma membrane
B. Capsule
C. Cell wall only
D. Flagellum

Answer: A. Plasma membrane

Explanation: The plasma membrane regulates movement of substances into and out of the bacterial cell.

MCQ 313

Which bacterial appendage is primarily associated with locomotion?

A. Flagellum
B. Fimbria
C. Capsule
D. Pilus

Answer: A. Flagellum

Explanation: Bacterial flagella are specialized structures that facilitate movement.

MCQ 314

Which bacterial appendages are generally shorter and more numerous than flagella?

A. Fimbriae
B. Pili
C. Endospores
D. Capsules

Answer: A. Fimbriae

Explanation: Fimbriae are short, hair-like structures that mainly help bacteria attach to surfaces.

MCQ 315

Which structure may facilitate genetic material transfer between bacterial cells?

A. Sex pilus
B. Capsule
C. Ribosome
D. Flagellar hook only

Answer: A. Sex pilus

Explanation: Sex pili can establish contact between bacterial cells during conjugation.

MCQ 316

Which of the following is NOT a nutritional mode characteristic of all bacteria?

A. Autotrophic nutrition
B. Heterotrophic nutrition
C. Saprophytic nutrition
D. Ingestion of food through a mouth-like opening

Answer: D. Ingestion of food through a mouth-like opening

Explanation: Bacteria do not possess a mouth or digestive tract. They absorb nutrients through their cell surface.

MCQ 317

A bacterium obtaining energy by oxidizing inorganic substances is an example of:

A. Chemoautotrophic nutrition
B. Holozoic nutrition
C. Saprophytic nutrition only
D. Parasitic nutrition only

Answer: A. Chemoautotrophic nutrition

Explanation: Chemoautotrophic bacteria obtain energy by oxidizing inorganic substances and use inorganic carbon sources for carbon assimilation.

MCQ 318

Which organisms can contribute significantly to nitrogen cycling through nitrogen fixation?

A. Certain cyanobacteria
B. All viruses
C. All fungi
D. All protozoans

Answer: A. Certain cyanobacteria

Explanation: Nitrogen-fixing cyanobacteria such as Nostoc and Anabaena contribute to nitrogen enrichment in ecosystems.

MCQ 319

Which structure in certain cyanobacteria provides a specialized environment for nitrogen fixation?

A. Heterocyst
B. Basidium
C. Ascus
D. Sporangium

Answer: A. Heterocyst

Explanation: Heterocysts are specialized cells associated with nitrogen fixation in certain filamentous cyanobacteria.

MCQ 320

Which statement about heterocysts is correct?

A. They are specialized nitrogen-fixing cells
B. They are fungal reproductive structures
C. They are viral protein coats
D. They are protozoan locomotory structures

Answer: A. They are specialized nitrogen-fixing cells

Explanation: Heterocysts are specialized cells in some cyanobacteria that provide conditions suitable for nitrogen fixation.

MCQ 321

Which group is primarily responsible for oxygenic photosynthesis among prokaryotes?

A. Cyanobacteria
B. Mycoplasma
C. Methanogens
D. Halophiles

Answer: A. Cyanobacteria

Explanation: Cyanobacteria perform oxygenic photosynthesis using chlorophyll a and release oxygen.

MCQ 322

Which of the following is a major ecological role of cyanobacteria?

A. Primary production and nitrogen fixation
B. Only decomposition of wood
C. Only parasitism of animals
D. Formation of fungal fruiting bodies

Answer: A. Primary production and nitrogen fixation

Explanation: Cyanobacteria contribute to photosynthetic primary production and, in some forms, nitrogen fixation.

MCQ 323

Which protist group is mainly photosynthetic and forms an important component of aquatic plankton?

A. Diatoms
B. Sporozoans
C. Amoebae
D. Slime moulds

Answer: A. Diatoms

Explanation: Diatoms are photosynthetic protists and important members of aquatic phytoplankton.

MCQ 324

Which of the following structures is unique to diatoms among the listed options?

A. Silica-containing frustule
B. Protein pellicle
C. Chitinous mycelium
D. Heterocyst

Answer: A. Silica-containing frustule

Explanation: Diatoms have a distinctive silica-impregnated cell wall called a frustule.

MCQ 325

Which protists are known for forming resistant silica-rich remains that accumulate in sediments?

A. Diatoms
B. Euglenoids
C. Amoebae
D. Sporozoans

Answer: A. Diatoms

Explanation: Silica-rich diatom frustules persist after death and accumulate to form diatomaceous deposits.

MCQ 326

Which protist group contains organisms with a proteinaceous pellicle rather than a rigid cell wall?

A. Euglenoids
B. Diatoms
C. Dinoflagellates
D. Slime moulds

Answer: A. Euglenoids

Explanation: Euglenoids have a flexible protein-rich pellicle.

MCQ 327

Which organism can switch between photosynthetic and heterotrophic nutrition depending on conditions?

A. Euglena
B. Agaricus
C. Rhizopus
D. Puccinia

Answer: A. Euglena

Explanation: Euglena can photosynthesize in light and obtain organic nutrients heterotrophically under suitable conditions.

MCQ 328

Which term best describes the nutritional flexibility of Euglena?

A. Mixotrophy
B. Holozoic nutrition
C. Chemolithotrophy
D. Autotrophy only

Answer: A. Mixotrophy

Explanation: Mixotrophy involves the ability to use more than one nutritional mode, as seen in Euglena.

MCQ 329

Which protist group is particularly associated with harmful algal blooms?

A. Dinoflagellates
B. Slime moulds
C. Amoebae
D. Ciliates

Answer: A. Dinoflagellates

Explanation: Rapid proliferation of some dinoflagellates produces harmful blooms, including red tides.

MCQ 330

The two flagella of typical dinoflagellates are usually arranged:

A. Both at the anterior end
B. One transversely and one longitudinally
C. Both inside the nucleus
D. One inside the chloroplast and one outside

Answer: B. One transversely and one longitudinally

Explanation: The transverse flagellum lies in a groove around the cell, while the longitudinal flagellum extends posteriorly.

MCQ 331

Which protist group develops a multinucleate plasmodium?

A. Slime moulds
B. Diatoms
C. Dinoflagellates
D. Euglenoids

Answer: A. Slime moulds

Explanation: Plasmodial slime moulds form multinucleate masses called plasmodia during their vegetative phase.

MCQ 332

Which of the following is a characteristic nutritional strategy of slime moulds?

A. Saprophytic nutrition
B. Photosynthesis only
C. Chemosynthesis only
D. Holozoic feeding through a mouth

Answer: A. Saprophytic nutrition

Explanation: Slime moulds feed on decaying organic matter.

MCQ 333

Which protozoan group includes organisms that use cilia for locomotion?

A. Ciliates
B. Amoeboids
C. Flagellates
D. Sporozoans

Answer: A. Ciliates

Explanation: Ciliates possess numerous short hair-like cilia used for locomotion and other functions.

MCQ 334

Which locomotory structure is characteristic of flagellated protozoans?

A. Flagellum
B. Pseudopodium
C. Cilium
D. Heterocyst

Answer: A. Flagellum

Explanation: Flagellated protozoans use one or more flagella for locomotion.

MCQ 335

Amoeboid movement is achieved primarily through:

A. Pseudopodia
B. Cilia
C. Flagella
D. Basidia

Answer: A. Pseudopodia

Explanation: Amoeboid protozoans extend temporary cytoplasmic projections called pseudopodia.

MCQ 336

Which protozoan group includes Plasmodium?

A. Sporozoans
B. Ciliates
C. Flagellates
D. Amoeboids

Answer: A. Sporozoans

Explanation: Plasmodium is traditionally placed among sporozoans.

MCQ 337

Which characteristic distinguishes fungi from animals?

A. Fungi generally absorb nutrients rather than ingesting food
B. Fungi are always prokaryotic
C. Fungi lack nuclei
D. Fungi contain no cell walls

Answer: A. Fungi generally absorb nutrients rather than ingesting food

Explanation: Fungi digest food externally and absorb dissolved nutrients, whereas animals generally ingest food.

MCQ 338

Which component of fungal hyphae increases the surface area available for nutrient absorption?

A. Extensive mycelial network
B. Viral capsid
C. Nucleoid
D. Heterocyst

Answer: A. Extensive mycelial network

Explanation: The branching mycelial network provides a large surface area for extracellular digestion and absorption.

MCQ 339

Which of the following is a typical fungal asexual reproductive structure?

A. Conidium
B. Basidium only
C. Heterocyst
D. Frustule

Answer: A. Conidium

Explanation: Conidia are asexual spores produced externally on specialized fungal structures called conidiophores.

MCQ 340

Conidia are generally:

A. Asexual spores
B. Sexual nuclei
C. Bacterial chromosomes
D. Viral capsids

Answer: A. Asexual spores

Explanation: Conidia are non-motile asexual spores produced by several groups of fungi.

MCQ 341

Which fungal structure is typically associated with production of conidia?

A. Conidiophore
B. Basidium
C. Ascus
D. Heterocyst

Answer: A. Conidiophore

Explanation: Conidiophores are specialized hyphae that bear conidia.

MCQ 342

Which reproductive process involves the fusion of two fungal nuclei?

A. Karyogamy
B. Plasmogamy
C. Fragmentation
D. Budding

Answer: A. Karyogamy

Explanation: Karyogamy is the fusion of two nuclei, generally following plasmogamy.

MCQ 343

Which event occurs first in the generalized fungal sexual cycle?

A. Plasmogamy
B. Karyogamy
C. Meiosis
D. Spore germination

Answer: A. Plasmogamy

Explanation: Plasmogamy generally precedes karyogamy, followed by meiosis in the sexual cycle.

MCQ 344

A cell containing two genetically distinct haploid nuclei is described as:

A. Dikaryotic
B. Diploid
C. Haploid
D. Polyploid

Answer: A. Dikaryotic

Explanation: A dikaryotic cell contains two separate haploid nuclei, represented as n+n.

MCQ 345

Which fungal group traditionally includes mushrooms?

A. Basidiomycetes
B. Phycomycetes
C. Deuteromycetes
D. Euglenoids

Answer: A. Basidiomycetes

Explanation: Mushrooms such as Agaricus are traditionally classified under Basidiomycetes.

MCQ 346

Which structure is commonly visible as the fruiting body of a mushroom?

A. Basidiocarp
B. Heterocyst
C. Sporangium
D. Ascus

Answer: A. Basidiocarp

Explanation: The mushroom fruiting body is a basidiocarp, which bears basidia.

MCQ 347

Which of the following is associated with rust disease?

A. Puccinia
B. Ustilago
C. Rhizopus
D. Mucor

Answer: A. Puccinia

Explanation: Puccinia is a parasitic rust fungus.

MCQ 348

Which organism is traditionally associated with smut disease?

A. Ustilago
B. Puccinia
C. Agaricus
D. Rhizopus

Answer: A. Ustilago

Explanation: Ustilago species are commonly known as smut fungi.

MCQ 349

Which fungal group traditionally includes organisms whose sexual reproductive stage was not known?

A. Deuteromycetes
B. Basidiomycetes
C. Ascomycetes
D. Phycomycetes

Answer: A. Deuteromycetes

Explanation: Deuteromycetes was a traditional grouping of fungi for which the sexual stage had not been observed.

MCQ 350

Which statement about Deuteromycetes is most appropriate for NCERT-based classification?

A. It was a traditional artificial group
B. It contained only prokaryotes
C. It contained only photosynthetic organisms
D. It was a kingdom separate from Fungi

Answer: A. It was a traditional artificial group

Explanation: Deuteromycetes was a traditional classification category based largely on the absence of a known sexual stage.

MCQ 351

Which organism is traditionally classified as a phycomycete?

A. Mucor
B. Agaricus
C. Puccinia
D. Alternaria

Answer: A. Mucor

Explanation: Mucor is traditionally included among Phycomycetes.

MCQ 352

Which organism is associated with bread mould?

A. Rhizopus
B. Agaricus
C. Puccinia
D. Ustilago

Answer: A. Rhizopus

Explanation: Rhizopus is commonly known as bread mould.

MCQ 353

Which fungal group commonly contains fungi with septate and branched hyphae?

A. Ascomycetes
B. All bacteria
C. Cyanobacteria
D. Viruses

Answer: A. Ascomycetes

Explanation: Members of Ascomycetes generally possess branched septate mycelium, although fungal diversity includes exceptions.

MCQ 354

Which structure separates many fungal hyphae into compartments?

A. Septa
B. Capsomeres
C. Heterocysts
D. Frustules

Answer: A. Septa

Explanation: Septa are cross-walls that divide hyphae into cellular compartments.

MCQ 355

Coenocytic hyphae are characterized by:

A. Absence of septa
B. Presence of many transverse septa
C. Absence of nuclei
D. Presence of chloroplasts

Answer: A. Absence of septa

Explanation: Coenocytic hyphae lack septa and contain a continuous cytoplasmic mass with multiple nuclei.

MCQ 356

Which of the following is NOT a fungal reproductive method?

A. Budding
B. Fragmentation
C. Spore formation
D. Binary fission as the characteristic method of all fungi

Answer: D. Binary fission as the characteristic method of all fungi

Explanation: Fungi reproduce through methods such as fragmentation, budding and spore formation; binary fission is not the characteristic reproductive method of fungi as a whole.

MCQ 357

Which fungal reproductive method is particularly characteristic of unicellular yeast?

A. Budding
B. Heterocyst formation
C. Plasmogamy only
D. Formation of frustules

Answer: A. Budding

Explanation: Yeast commonly reproduces asexually by budding.

MCQ 358

Which structure is absent in a viroid?

A. RNA
B. Protein capsid
C. Circular nucleic acid
D. Infectious genetic material

Answer: B. Protein capsid

Explanation: Viroids are naked circular RNA molecules and do not have a protein capsid.

MCQ 359

Which statement correctly distinguishes prions from viroids?

A. Prions are infectious proteins, whereas viroids are infectious RNA molecules
B. Prions are bacteria, whereas viroids are fungi
C. Both contain DNA
D. Both possess protein capsids

Answer: A. Prions are infectious proteins, whereas viroids are infectious RNA molecules

Explanation: Prions are infectious proteinaceous particles, while viroids are small infectious RNA molecules.

MCQ 360

Which of the following represents the correct increasing level of cellular organization?

A. Virus → prokaryotic cell → eukaryotic cell
B. Eukaryotic cell → virus → prokaryotic cell
C. Prokaryotic cell → virus → eukaryotic cell
D. Virus → eukaryotic cell → prokaryotic cell

Answer: A. Virus → prokaryotic cell → eukaryotic cell

Explanation: Viruses are acellular, prokaryotes have cellular organization without a membrane-bound nucleus, and eukaryotes possess a membrane-bound nucleus and membrane-bound organelles.

MCQ 361

Which feature most directly distinguishes prokaryotic cells from eukaryotic cells?

A. Presence of ribosomes
B. Presence of plasma membrane
C. Absence of a membrane-bound nucleus
D. Presence of genetic material

Answer: C. Absence of a membrane-bound nucleus

Explanation: Prokaryotic cells lack a membrane-bound nucleus. Their genetic material lies in a nucleoid region.

MCQ 362

Which component is characteristic of the cell wall of most eubacteria?

A. Chitin
B. Peptidoglycan
C. Cellulose
D. Silica

Answer: B. Peptidoglycan

Explanation: Most eubacterial cell walls contain peptidoglycan (murein), which provides structural strength.

MCQ 363

Archaebacteria differ from many eubacteria particularly in their

A. Absence of DNA
B. Membrane lipid composition and cell wall structure
C. Absence of ribosomes
D. Lack of plasma membrane

Answer: B. Membrane lipid composition and cell wall structure

Explanation: Archaeal membranes have distinctive ether-linked lipids, and their cell walls do not contain the typical bacterial peptidoglycan.

MCQ 364

Which group is especially associated with extremely saline habitats?

A. Methanogens
B. Halophiles
C. Cyanobacteria
D. Mycoplasmas

Answer: B. Halophiles

Explanation: Halophilic archaea thrive in highly saline environments such as salt lakes and salt-rich habitats.

MCQ 365

Methanogens are important contributors to the production of

A. Oxygen
B. Methane
C. Nitrogen
D. Hydrogen peroxide

Answer: B. Methane

Explanation: Methanogenic archaea produce methane as a metabolic end product under anaerobic conditions.

MCQ 366

Which organism is most appropriately associated with biogas production?

A. Methanobacterium
B. Amoeba
C. Chlamydomonas
D. Rhizopus

Answer: A. Methanobacterium

Explanation: Methanogens such as Methanobacterium occur in anaerobic environments and contribute to methane formation in biogas plants.

MCQ 367

The absence of a cell wall in Mycoplasma makes it particularly

A. Rigid
B. Flexible in shape
C. Photosynthetic
D. Multicellular

Answer: B. Flexible in shape

Explanation: Mycoplasmas lack a cell wall, so their plasma membrane allows considerable variation in cell shape.

MCQ 368

Which structure of bacteria primarily helps in attachment to surfaces?

A. Fimbriae
B. Nucleoid
C. Mesosome
D. Ribosome

Answer: A. Fimbriae

Explanation: Fimbriae are short, hair-like structures involved mainly in attachment to surfaces.

MCQ 369

The sex pilus of bacteria is mainly associated with

A. Photosynthesis
B. Conjugation
C. Respiration
D. Endospore formation

Answer: B. Conjugation

Explanation: Sex pili facilitate contact between bacterial cells during conjugative transfer of genetic material.

MCQ 370

Which bacterial structure is primarily involved in locomotion?

A. Capsule
B. Flagellum
C. Fimbria
D. Ribosome

Answer: B. Flagellum

Explanation: Bacterial flagella are locomotory structures that enable movement in suitable environments.

MCQ 371

A bacterium having a single flagellum at one pole is described as

A. Peritrichous
B. Monotrichous
C. Amphitrichous
D. Atrichous

Answer: B. Monotrichous

Explanation: Monotrichous bacteria possess a single flagellum, generally at one pole.

MCQ 372

Bacteria that obtain energy by oxidising inorganic substances are generally called

A. Photoheterotrophs
B. Chemoautotrophs
C. Saprophytes
D. Parasites

Answer: B. Chemoautotrophs

Explanation: Chemoautotrophic bacteria obtain energy by oxidising inorganic substances and use carbon dioxide as a carbon source.

MCQ 373

Which group is especially important for nitrogen fixation among cyanobacteria?

A. Cells of heterocysts
B. Gas vacuoles
C. Hormogonia only
D. Akinetes only

Answer: A. Cells of heterocysts

Explanation: Heterocysts are specialised cells in certain cyanobacteria and provide a suitable microenvironment for nitrogen fixation.

MCQ 374

The pigments called phycobilins are characteristic accessory pigments of

A. Cyanobacteria
B. Fungi
C. Protozoans
D. Archaea

Answer: A. Cyanobacteria

Explanation: Cyanobacteria contain phycobilin pigments such as phycocyanin and phycoerythrin in addition to chlorophyll-a.

MCQ 375

Which statement about cyanobacteria is correct?

A. They are eukaryotic algae
B. They possess a membrane-bound nucleus
C. They are prokaryotic organisms capable of photosynthesis
D. They lack photosynthetic pigments

Answer: C. They are prokaryotic organisms capable of photosynthesis

Explanation: Cyanobacteria are photosynthetic prokaryotes and are therefore included under Monera in the traditional five-kingdom classification.

MCQ 376

The silica-containing outer covering of diatoms is known as

A. Pellicle
B. Frustule
C. Capsule
D. Peridium

Answer: B. Frustule

Explanation: Diatoms possess a siliceous cell wall called a frustule, consisting of two overlapping halves.

MCQ 377

Diatomaceous earth is mainly formed from

A. Calcium carbonate shells
B. Siliceous remains of diatoms
C. Fungal spores
D. Bacterial capsules

Answer: B. Siliceous remains of diatoms

Explanation: Accumulated deposits of the silica-rich remains of diatoms form diatomaceous earth.

MCQ 378

Which property of diatomaceous deposits makes them useful for filtration?

A. High protein content
B. Porous nature
C. High carbohydrate content
D. Ability to photosynthesise

Answer: B. Porous nature

Explanation: Diatomaceous deposits are porous and can therefore be used as filtering material.

MCQ 379

A characteristic feature of dinoflagellates is the presence of

A. Two flagella
B. No cell covering
C. Chitinous hyphae
D. Pseudopodia only

Answer: A. Two flagella

Explanation: Dinoflagellates generally possess two flagella, with one lying longitudinally and the other transversely.

MCQ 380

The phenomenon of red tide is frequently associated with rapid multiplication of

A. Dinoflagellates
B. Basidiomycetes
C. Archaebacteria
D. Slime moulds

Answer: A. Dinoflagellates

Explanation: Certain dinoflagellates multiply rapidly and may release toxins, producing red or brown discoloration of seawater.

MCQ 381

The body covering of Euglena is called

A. Frustule
B. Pellicle
C. Capsule
D. Cellulose wall

Answer: B. Pellicle

Explanation: Euglenoids possess a flexible protein-rich pellicle instead of a conventional cellulose cell wall.

MCQ 382

Mixotrophic nutrition in Euglena means that it can

A. Only ingest bacteria
B. Only photosynthesise
C. Use both autotrophic and heterotrophic modes depending on conditions
D. Obtain food only from dead organisms

Answer: C. Use both autotrophic and heterotrophic modes depending on conditions

Explanation: Euglena can photosynthesise in light and may obtain organic nutrients heterotrophically under suitable conditions.

MCQ 383

Slime moulds are generally found on

A. Dry desert rocks only
B. Decaying organic matter
C. Living animal tissues only
D. Deep ocean sediments only

Answer: B. Decaying organic matter

Explanation: Slime moulds are saprophytic protists that commonly grow on decaying organic matter.

MCQ 384

The multinucleate feeding stage of a plasmodial slime mould is called

A. Mycelium
B. Plasmodium
C. Protonema
D. Basidium

Answer: B. Plasmodium

Explanation: The vegetative feeding phase of plasmodial slime moulds is a multinucleate mass of cytoplasm called plasmodium.

MCQ 385

Which protozoan group characteristically uses pseudopodia for locomotion?

A. Amoeboid protozoans
B. Ciliated protozoans
C. Flagellated protozoans
D. Sporozoans

Answer: A. Amoeboid protozoans

Explanation: Amoeboid protozoans move and capture food using temporary cytoplasmic projections called pseudopodia.

MCQ 386

The locomotory structures of ciliated protozoans are

A. Flagella
B. Cilia
C. Pseudopodia
D. Hyphae

Answer: B. Cilia

Explanation: Ciliated protozoans possess numerous short hair-like cilia that help in locomotion and, in some forms, feeding.

MCQ 387

Which nutritional mode is most characteristic of fungi?

A. Ingestive autotrophy
B. Absorptive heterotrophy
C. Photosynthetic autotrophy
D. Chemosynthetic autotrophy

Answer: B. Absorptive heterotrophy

Explanation: Fungi digest organic matter externally and absorb the resulting soluble nutrients.

MCQ 388

The fungal body is commonly composed of a network of

A. Rhizoids only
B. Hyphae
C. Pseudopodia
D. Cilia

Answer: B. Hyphae

Explanation: Individual thread-like fungal structures are called hyphae. A mass/network of hyphae forms the mycelium.

MCQ 389

A fungal mycelium consisting of hyphae without septa is described as

A. Septate
B. Coenocytic
C. Dikaryotic
D. Cellular

Answer: B. Coenocytic

Explanation: Coenocytic hyphae lack cross walls or septa and contain a continuous multinucleate cytoplasm.

MCQ 390

Which fungal reproductive structure produces conidia?

A. Conidiophore
B. Basidium
C. Ascocarp only
D. Zygote

Answer: A. Conidiophore

Explanation: Conidia are asexual spores produced externally on specialised hyphae called conidiophores.

MCQ 391

The fusion of cytoplasm between two compatible fungal cells is called

A. Karyogamy
B. Plasmogamy
C. Meiosis
D. Sporulation

Answer: B. Plasmogamy

Explanation: Plasmogamy is the fusion of cytoplasms. Nuclear fusion, which may occur later, is called karyogamy.

MCQ 392

The fusion of two fungal nuclei is termed

A. Plasmolysis
B. Karyogamy
C. Budding
D. Fragmentation

Answer: B. Karyogamy

Explanation: Karyogamy is the fusion of two compatible nuclei following plasmogamy.

MCQ 393

A dikaryotic fungal cell contains

A. No nucleus
B. One haploid nucleus
C. Two genetically compatible nuclei
D. Four diploid nuclei

Answer: C. Two genetically compatible nuclei

Explanation: A dikaryotic condition contains two separate nuclei, typically represented as n + n, before nuclear fusion.

MCQ 394

In basidiomycetes, sexual spores are generally produced externally on

A. Asci
B. Basidia
C. Sporangia
D. Conidiophores

Answer: B. Basidia

Explanation: Basidia are club-shaped reproductive structures on which basidiospores are produced externally.

MCQ 395

In ascomycetes, the characteristic sexual spores are

A. Basidiospores
B. Ascospores
C. Conidia
D. Zoospores

Answer: B. Ascospores

Explanation: Ascospores are produced inside sac-like structures called asci, characteristic of Ascomycetes.

MCQ 396

Which organism is traditionally placed among basidiomycetes?

A. Agaricus
B. Rhizopus
C. Saccharomyces
D. Mucor

Answer: A. Agaricus

Explanation: Agaricus, commonly represented by mushrooms, is traditionally classified under Basidiomycetes.

MCQ 397

Rust disease of plants is traditionally associated with

A. Puccinia
B. Rhizopus
C. Agaricus
D. Mucor

Answer: A. Puccinia

Explanation: Puccinia is a traditional example of Basidiomycetes and is associated with rust diseases of plants.

MCQ 398

Which fungal group was traditionally known as the “imperfect fungi” because only the asexual or vegetative stages were known?

A. Phycomycetes
B. Ascomycetes
C. Basidiomycetes
D. Deuteromycetes

Answer: D. Deuteromycetes

Explanation: Deuteromycetes was a traditional artificial group comprising fungi for which sexual stages were not known. Many have since been placed in other fungal groups based on modern classification.

MCQ 399

A lichen represents a symbiotic association between

A. Bacterium and protozoan
B. Fungus and alga/cyanobacterium
C. Fungus and virus
D. Alga and protozoan

Answer: B. Fungus and alga/cyanobacterium

Explanation: Lichens are mutualistic associations in which the fungal partner provides protection and structural support, while the photosynthetic partner contributes organic food.

MCQ 400

Which statement correctly describes a virus?

A. It is a cellular organism with a complete metabolic system
B. It contains both DNA and RNA as its genetic material simultaneously
C. It consists of nucleic acid enclosed within a protein coat
D. It possesses ribosomes for independent protein synthesis

Answer: C. It consists of nucleic acid enclosed within a protein coat

Explanation: A typical virus contains either DNA or RNA as genetic material enclosed within a protein coat called the capsid. Viruses lack cellular organisation and independent protein-synthesising machinery.

MCQ 401

Whittaker’s five-kingdom classification was primarily based on all of the following EXCEPT

A. Cell structure
B. Body organisation
C. Mode of nutrition
D. Economic importance

Answer: D. Economic importance

Explanation: Whittaker considered cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships.

MCQ 402

Which kingdom includes organisms that are predominantly unicellular eukaryotes?

A. Monera
B. Protista
C. Fungi
D. Plantae

Answer: B. Protista

Explanation: Protista primarily includes unicellular eukaryotic organisms, although some forms have more complex organisation.

MCQ 403

Which combination is correctly matched?

A. Monera — eukaryotic
B. Protista — prokaryotic
C. Fungi — heterotrophic eukaryotes
D. Plantae — absorptive heterotrophs

Answer: C. Fungi — heterotrophic eukaryotes

Explanation: Fungi are eukaryotic and generally obtain nutrition by absorption of organic substances.

MCQ 404

The kingdom Monera differs fundamentally from Protista because Monerans

A. Lack DNA
B. Lack a membrane-bound nucleus
C. Lack ribosomes
D. Are always multicellular

Answer: B. Lack a membrane-bound nucleus

Explanation: Monerans are prokaryotes, whereas protists are eukaryotes with a membrane-bound nucleus.

MCQ 405

Which of the following is NOT a characteristic feature of prokaryotes?

A. Nucleoid
B. 70S ribosomes
C. Membrane-bound nucleus
D. Plasma membrane

Answer: C. Membrane-bound nucleus

Explanation: Prokaryotes have a nucleoid rather than a membrane-bound nucleus.

MCQ 406

The genetic material in a typical bacterial cell is primarily located in the

A. Nucleus
B. Nucleoid
C. Golgi apparatus
D. Endoplasmic reticulum

Answer: B. Nucleoid

Explanation: The bacterial chromosome is located in the nucleoid region, which is not surrounded by a nuclear membrane.

MCQ 407

Which combination represents the correct sequence of increasing organisational complexity?

A. Eukaryote → prokaryote → virus
B. Virus → prokaryote → eukaryote
C. Eukaryote → virus → prokaryote
D. Prokaryote → virus → eukaryote

Answer: B. Virus → prokaryote → eukaryote

Explanation: Viruses are acellular; prokaryotes are cellular but lack a membrane-bound nucleus; eukaryotes possess membrane-bound organelles and a nucleus.

MCQ 408

Which bacterial structure may protect a bacterial cell against desiccation and phagocytosis?

A. Capsule
B. Ribosome
C. Nucleoid
D. Flagellum

Answer: A. Capsule

Explanation: A capsule or slime layer can provide protection and may contribute to resistance against adverse conditions and host defence mechanisms.

MCQ 409

Which bacterial structure is primarily associated with genetic exchange rather than locomotion?

A. Flagellum
B. Sex pilus
C. Capsule
D. Endospore

Answer: B. Sex pilus

Explanation: Sex pili participate in conjugation, facilitating transfer of genetic material between bacterial cells.

MCQ 410

Which statement about bacterial ribosomes is correct?

A. They are 80S
B. They are 70S
C. They are absent
D. They are membrane-bound

Answer: B. They are 70S

Explanation: Typical prokaryotic ribosomes are 70S and consist of 50S and 30S subunits.

MCQ 411

Which bacterial nutritional category uses light energy but obtains carbon from organic compounds?

A. Photoheterotrophic
B. Chemoautotrophic
C. Photoautotrophic
D. Chemoautotrophic only

Answer: A. Photoheterotrophic

Explanation: Photoheterotrophs use light as an energy source but depend on organic compounds as their carbon source.

MCQ 412

Organisms that obtain both energy and carbon from organic compounds are generally

A. Photoautotrophs
B. Chemoheterotrophs
C. Chemoautotrophs
D. Photoautotrophs only

Answer: B. Chemoheterotrophs

Explanation: Chemoheterotrophs obtain energy through chemical compounds and use organic substances as carbon sources.

MCQ 413

Which of the following is a correct example of an oxygenic photosynthetic prokaryote?

A. Cyanobacterium
B. Mycoplasma
C. Methanogen
D. Amoeba

Answer: A. Cyanobacterium

Explanation: Cyanobacteria perform oxygenic photosynthesis and release oxygen.

MCQ 414

The oxygen released during photosynthesis by cyanobacteria originates primarily from

A. Carbon dioxide
B. Water
C. Glucose
D. Chlorophyll

Answer: B. Water

Explanation: In oxygenic photosynthesis, water is split during the light reactions, releasing oxygen.

MCQ 415

Which cyanobacterial structure is specialised for nitrogen fixation?

A. Heterocyst
B. Pellicle
C. Frustule
D. Basidium

Answer: A. Heterocyst

Explanation: Heterocysts provide specialised conditions suitable for nitrogen fixation by nitrogenase.

MCQ 416

Which one is correctly associated with cyanobacteria?

A. Chlorophyll-a and phycobilins
B. Chitin and ergosterol
C. Frustule and silica only
D. Pellicle and paramylon only

Answer: A. Chlorophyll-a and phycobilins

Explanation: Cyanobacteria contain chlorophyll-a and accessory pigments such as phycobilins.

MCQ 417

Which organism is traditionally placed in Monera despite sometimes being called a “blue-green alga”?

A. Nostoc
B. Amoeba
C. Euglena
D. Chlorella

Answer: A. Nostoc

Explanation: Nostoc is a cyanobacterium and therefore a prokaryote, not a true eukaryotic alga.

MCQ 418

Which protistan group is particularly important as a major component of marine phytoplankton?

A. Diatoms
B. Amoebae
C. Slime moulds
D. Sporozoans

Answer: A. Diatoms

Explanation: Diatoms are important photosynthetic organisms and major components of phytoplankton.

MCQ 419

The cell wall of diatoms is predominantly impregnated with

A. Chitin
B. Silica
C. Peptidoglycan
D. Lignin

Answer: B. Silica

Explanation: Diatom cell walls contain silica and form characteristic frustules.

MCQ 420

Diatoms are often considered important primary producers because they

A. Perform photosynthesis
B. Consume all other phytoplankton
C. Are heterotrophic fungi
D. Produce methane

Answer: A. Perform photosynthesis

Explanation: Diatoms are photosynthetic and contribute substantially to primary production in aquatic ecosystems.

MCQ 421

Which protists are commonly responsible for harmful algal blooms called red tides?

A. Dinoflagellates
B. Diatoms only
C. Slime moulds
D. Amoeboid protozoans

Answer: A. Dinoflagellates

Explanation: Certain dinoflagellates can multiply explosively and produce pigments and toxins, resulting in red tides.

MCQ 422

The two flagella of typical dinoflagellates are arranged

A. Both longitudinally
B. One longitudinally and one transversely
C. Both transversely
D. Around the nucleus

Answer: B. One longitudinally and one transversely

Explanation: One flagellum lies longitudinally and the other transversely in the characteristic dinoflagellate arrangement.

MCQ 423

Which protist has a flexible pellicle instead of a typical cell wall?

A. Euglena
B. Diatom
C. Dinoflagellate
D. Amoeba

Answer: A. Euglena

Explanation: Euglenoids possess a protein-rich pellicle that provides flexibility.

MCQ 424

The ability of Euglena to switch between nutritional modes demonstrates

A. Parasitism only
B. Mixotrophy
C. Saprophytism only
D. Chemosynthesis

Answer: B. Mixotrophy

Explanation: Euglena can photosynthesise in light and obtain organic nutrients heterotrophically under appropriate conditions.

MCQ 425

Which group is best known for forming a multinucleate plasmodial stage?

A. Slime moulds
B. Diatoms
C. Dinoflagellates
D. Cyanobacteria

Answer: A. Slime moulds

Explanation: Plasmodial slime moulds form a multinucleate, creeping feeding stage called plasmodium.

MCQ 426

Slime moulds generally obtain their nutrients by

A. Photosynthesis
B. Absorption of decaying organic matter
C. Nitrogen fixation
D. Methanogenesis

Answer: B. Absorption of decaying organic matter

Explanation: Slime moulds are saprophytic organisms associated with decaying organic material.

MCQ 427

Which protozoan group is generally characterised by flagella?

A. Flagellated protozoans
B. Ciliated protozoans
C. Amoeboid protozoans
D. Sporozoans

Answer: A. Flagellated protozoans

Explanation: Flagellated protozoans use one or more flagella for locomotion and sometimes food acquisition.

MCQ 428

Sporozoans are generally characterised by

A. Prominent locomotory organelles in adult stages
B. An exclusively photosynthetic mode of nutrition
C. An absence of prominent locomotory structures in many stages
D. Siliceous cell walls

Answer: C. An absence of prominent locomotory structures in many stages

Explanation: Sporozoans are generally non-motile in their adult stages and include parasitic forms.

MCQ 429

Which characteristic is common to fungi?

A. Photosynthetic nutrition in all members
B. Chitinous cell wall
C. Prokaryotic organisation
D. Siliceous cell wall

Answer: B. Chitinous cell wall

Explanation: The fungal cell wall is characteristically composed largely of chitin.

MCQ 430

The reserve food material commonly associated with fungi is

A. Starch
B. Glycogen
C. Cellulose
D. Sucrose

Answer: B. Glycogen

Explanation: Fungi generally store food reserves mainly in the form of glycogen and oils.

MCQ 431

Which mode of fungal nutrition involves obtaining nutrients from dead organic matter?

A. Saprophytic
B. Autotrophic
C. Photosynthetic
D. Chemosynthetic

Answer: A. Saprophytic

Explanation: Saprophytic fungi obtain nutrients from dead and decaying organic material.

MCQ 432

A fungus obtaining nutrients from a living host is described as

A. Saprophytic
B. Parasitic
C. Autotrophic
D. Photoheterotrophic

Answer: B. Parasitic

Explanation: Parasitic fungi obtain nutrients from living hosts and may cause diseases.

MCQ 433

A symbiotic association between fungal hyphae and photosynthetic organisms is represented by

A. Mycorrhiza
B. Lichen
C. Plasmodium
D. Frustule

Answer: B. Lichen

Explanation: Lichens consist of a fungal partner associated with an alga or cyanobacterium.

MCQ 434

In a lichen, the photosynthetic partner is called

A. Mycobiont
B. Phycobiont
C. Basidiobiont
D. Sporobiont

Answer: B. Phycobiont

Explanation: The algal or cyanobacterial partner is called the phycobiont, while the fungal partner is the mycobiont.

MCQ 435

The fungal partner of a lichen is called

A. Phycobiont
B. Mycobiont
C. Cyanobiont
D. Protobiont

Answer: B. Mycobiont

Explanation: The fungal component of the lichen is called the mycobiont.

MCQ 436

Lichens are useful as indicators of

A. Soil fertility only
B. Air pollution
C. Ocean salinity
D. Methane concentration

Answer: B. Air pollution

Explanation: Lichens are sensitive to air pollutants and are therefore useful bioindicators of air quality.

MCQ 437

Mycorrhiza represents an association between

A. Fungus and plant roots
B. Alga and fungus only
C. Bacterium and virus
D. Protozoan and plant root

Answer: A. Fungus and plant roots

Explanation: Mycorrhiza is a mutualistic association between fungal hyphae and plant roots.

MCQ 438

In mycorrhizal associations, the fungus can particularly assist the plant in

A. Absorption of water and minerals
B. Production of DNA
C. Formation of ribosomes
D. Conversion of oxygen into nitrogen

Answer: A. Absorption of water and minerals

Explanation: Fungal hyphae increase the effective absorptive area of roots and can improve mineral and water acquisition.

MCQ 439

Which fungal structure is specifically associated with asexual reproduction by conidia?

A. Conidiophore
B. Basidium
C. Ascogonium only
D. Zygospore

Answer: A. Conidiophore

Explanation: Conidiophores bear asexual spores called conidia externally.

MCQ 440

Which fungal reproductive structure contains ascospores?

A. Basidium
B. Ascus
C. Sporangium
D. Conidiophore

Answer: B. Ascus

Explanation: Ascospores are produced inside sac-like asci in ascomycetes.

MCQ 441

Basidiospores are produced

A. Inside asci
B. Externally on basidia
C. Inside bacterial capsules
D. Inside diatom frustules

Answer: B. Externally on basidia

Explanation: Basidia produce basidiospores externally.

MCQ 442

Which of the following is a characteristic feature of Basidiomycetes?

A. Basidiospores
B. Frustules
C. Pellicle
D. Heterocysts

Answer: A. Basidiospores

Explanation: Basidiospores are characteristic sexual spores of basidiomycetes.

MCQ 443

Which traditional fungal group includes bread moulds such as Rhizopus?

A. Phycomycetes
B. Basidiomycetes
C. Ascomycetes
D. Deuteromycetes

Answer: A. Phycomycetes

Explanation: In the traditional NCERT classification, Rhizopus is included under Phycomycetes.

MCQ 444

Rhizopus commonly reproduces asexually through

A. Basidiospores
B. Sporangiospores
C. Ascospores
D. Conidia only

Answer: B. Sporangiospores

Explanation: Rhizopus forms sporangia containing numerous sporangiospores.

MCQ 445

The reproductive structure containing sporangiospores in Rhizopus is the

A. Basidium
B. Sporangium
C. Ascus
D. Conidiophore

Answer: B. Sporangium

Explanation: Sporangiospores are formed inside sporangia.

MCQ 446

Which fungal genus is traditionally associated with yeast?

A. Saccharomyces
B. Puccinia
C. Agaricus
D. Ustilago

Answer: A. Saccharomyces

Explanation: Saccharomyces is a unicellular yeast traditionally classified among Ascomycetes.

MCQ 447

Asexual reproduction in yeast commonly occurs by

A. Budding
B. Fragmentation into basidia
C. Binary fission only
D. Formation of frustules

Answer: A. Budding

Explanation: Yeast commonly reproduces asexually by budding.

MCQ 448

Which of the following is a traditional example of an ascomycete?

A. Saccharomyces
B. Agaricus
C. Puccinia
D. Ustilago

Answer: A. Saccharomyces

Explanation: Saccharomyces is traditionally classified under Ascomycetes.

MCQ 449

The characteristic sexual reproductive structure of Ascomycetes is

A. Ascus
B. Basidium
C. Sporangium
D. Heterocyst

Answer: A. Ascus

Explanation: The ascus is the sac-like structure in which ascospores are formed.

MCQ 450

Which fungal group includes many mushrooms?

A. Basidiomycetes
B. Monera
C. Dinoflagellates
D. Deuteromycetes only

Answer: A. Basidiomycetes

Explanation: Many familiar mushrooms belong to Basidiomycetes.

MCQ 451

Which one is correctly matched?

A. Puccinia — rust
B. Ustilago — diatom
C. Agaricus — cyanobacterium
D. Rhizopus — dinoflagellate

Answer: A. Puccinia — rust

Explanation: Puccinia is traditionally associated with rust diseases.

MCQ 452

Ustilago is traditionally associated with

A. Smut diseases
B. Red tides
C. Methane production
D. Diatomaceous deposits

Answer: A. Smut diseases

Explanation: Ustilago is traditionally recognised as a basidiomycete associated with smut diseases.

MCQ 453

The dikaryotic phase is particularly well developed in

A. Basidiomycetes
B. Cyanobacteria
C. Dinoflagellates
D. Bacteria

Answer: A. Basidiomycetes

Explanation: In basidiomycetes, the dikaryotic phase is prolonged and forms a major part of the life cycle.

MCQ 454

Which sequence correctly represents major events in fungal sexual reproduction?

A. Karyogamy → plasmogamy → meiosis
B. Plasmogamy → karyogamy → meiosis
C. Meiosis → plasmogamy → karyogamy
D. Plasmogamy → meiosis → karyogamy in all fungi

Answer: B. Plasmogamy → karyogamy → meiosis

Explanation: In the general pattern, cytoplasmic fusion occurs first, followed by nuclear fusion and subsequently meiosis.

MCQ 455

The stage between plasmogamy and karyogamy in many fungi may be

A. Dikaryotic
B. Diploid permanently
C. Prokaryotic
D. Acellular

Answer: A. Dikaryotic

Explanation: After plasmogamy, two compatible nuclei may remain separate, producing an n+n dikaryotic stage.

MCQ 456

Which statement about Deuteromycetes is appropriate for NCERT-based preparation?

A. It is a traditional group containing fungi with unknown sexual stages
B. It contains only bacteria
C. It contains only cyanobacteria
D. It is another name for Basidiomycetes

Answer: A. It is a traditional group containing fungi with unknown sexual stages

Explanation: Deuteromycetes is a traditional artificial grouping. Modern fungal classification has reassigned many of its members.

MCQ 457

Which fungal group was historically called “imperfect fungi”?

A. Ascomycetes
B. Basidiomycetes
C. Deuteromycetes
D. Phycomycetes

Answer: C. Deuteromycetes

Explanation: The term “imperfect fungi” was historically applied because sexual reproductive stages were not known for these fungi.

MCQ 458

Which pair represents asexual fungal spores?

A. Conidia and sporangiospores
B. Ascospores and basidiospores
C. Zygospores and ascospores
D. Basidiospores and zygospores

Answer: A. Conidia and sporangiospores

Explanation: Conidia and sporangiospores are asexual spores, whereas ascospores and basidiospores are sexual spores.

MCQ 459

Which pair consists of sexual fungal spores?

A. Conidia and sporangiospores
B. Ascospores and basidiospores
C. Conidia and zoospores
D. Sporangiospores and conidia

Answer: B. Ascospores and basidiospores

Explanation: Ascospores are sexual spores of ascomycetes and basidiospores are sexual spores of basidiomycetes.

MCQ 460

Which statement about fungal hyphae is correct?

A. All fungal hyphae are necessarily unicellular
B. Hyphae may be septate or aseptate
C. Hyphae are characteristic of bacteria
D. Hyphae contain no cytoplasm

Answer: B. Hyphae may be septate or aseptate

Explanation: Fungal hyphae may possess septa or may be coenocytic and aseptate.

MCQ 461

A collection of fungal hyphae is called

A. Mycelium
B. Plasmodium
C. Frustule
D. Pellicle

Answer: A. Mycelium

Explanation: A network or mass of hyphae forms the mycelium.

MCQ 462

Which statement best distinguishes a virus from a cellular organism?

A. Virus contains genetic material
B. Virus can undergo genetic variation
C. Virus lacks cellular organisation
D. Virus contains proteins

Answer: C. Virus lacks cellular organisation

Explanation: Viruses contain nucleic acid and proteins but do not possess cellular organisation.

MCQ 463

A complete infectious virus particle outside a host cell is called a

A. Virion
B. Viroid
C. Prion
D. Capsomere

Answer: A. Virion

Explanation: A complete mature infectious viral particle is called a virion.

MCQ 464

The protein coat surrounding the viral genome is called

A. Capsid
B. Capsule
C. Cell wall
D. Pellicle

Answer: A. Capsid

Explanation: The capsid is the protein covering surrounding the viral nucleic acid.

MCQ 465

The individual protein subunits forming a viral capsid are called

A. Capsomeres
B. Ribosomes
C. Peptidoglycans
D. Basidia

Answer: A. Capsomeres

Explanation: Capsomeres are structural protein subunits that assemble to form the viral capsid.

MCQ 466

Which statement about viral genetic material is correct?

A. Every virus contains both DNA and RNA
B. Viruses contain either DNA or RNA as genetic material
C. Viruses never contain nucleic acid
D. Viral genetic material is always double-stranded DNA

Answer: B. Viruses contain either DNA or RNA as genetic material

Explanation: In the standard NCERT treatment, viral genomes are composed of either DNA or RNA.

MCQ 467

Which structure is characteristic of many bacteriophages?

A. Head and tail
B. Frustule
C. Pellicle
D. Heterocyst

Answer: A. Head and tail

Explanation: Many bacteriophages, such as T4, possess a protein head containing genetic material and a tail structure involved in attachment and genome delivery.

MCQ 468

A bacteriophage infects

A. Fungi
B. Bacteria
C. Plants only
D. Protozoans only

Answer: B. Bacteria

Explanation: Bacteriophages are viruses that infect bacterial cells.

MCQ 469

During viral replication, the host cell is primarily used for

A. Independent photosynthesis by the virus
B. Synthesis and assembly of viral components
C. Production of bacterial ribosomes by the virus
D. Formation of fungal hyphae

Answer: B. Synthesis and assembly of viral components

Explanation: Viruses depend on host cellular machinery for replication and synthesis of viral components.

MCQ 470

The ability of viruses to be crystallised outside a host was historically used as evidence of their

A. Cellular nature
B. Non-cellular nature
C. Photosynthetic nature
D. Bacterial nature

Answer: B. Non-cellular nature

Explanation: Viruses can exist in a crystallised state outside host cells, unlike typical cellular organisms.

MCQ 471

Which of the following is NOT a component of a typical naked virus?

A. Nucleic acid
B. Capsid
C. Ribosome
D. Capsomeres

Answer: C. Ribosome

Explanation: Viruses lack ribosomes and depend on host cells for protein synthesis.

MCQ 472

Viroids differ from viruses primarily because viroids

A. Contain protein capsids
B. Are composed of small naked RNA molecules
C. Always contain DNA
D. Possess ribosomes

Answer: B. Are composed of small naked RNA molecules

Explanation: Viroids are small, circular, single-stranded RNA molecules without a protein coat.

MCQ 473

Viroids are particularly associated with

A. Plant diseases
B. Bacterial conjugation
C. Methane production
D. Fungal nutrition

Answer: A. Plant diseases

Explanation: Viroids are known to cause various plant diseases.

MCQ 474

Which infectious agent is composed essentially of protein and lacks nucleic acid?

A. Virus
B. Viroid
C. Prion
D. Bacteriophage

Answer: C. Prion

Explanation: Prions are infectious misfolded proteins and do not contain DNA or RNA.

MCQ 475

Which condition is historically associated with prions?

A. Bovine spongiform encephalopathy
B. Malaria
C. Red tide
D. Rust disease

Answer: A. Bovine spongiform encephalopathy

Explanation: Bovine spongiform encephalopathy (BSE), commonly called mad cow disease, is associated with prions.

MCQ 476

Which sequence correctly represents the organisation from acellular to cellular?

A. Virus → prokaryote → eukaryote
B. Prokaryote → virus → eukaryote
C. Eukaryote → prokaryote → virus
D. Virus → eukaryote → prokaryote

Answer: A. Virus → prokaryote → eukaryote

Explanation: Viruses are acellular, prokaryotes are cellular without a membrane-bound nucleus, and eukaryotes possess a membrane-bound nucleus.

MCQ 477

Which pair is correctly matched?

A. Viroid — infectious protein
B. Prion — naked circular RNA
C. Virus — nucleic acid with protein coat
D. Bacterium — acellular particle

Answer: C. Virus — nucleic acid with protein coat

Explanation: Viruses contain nucleic acid enclosed within a protein coat; viroids are naked RNA and prions are infectious proteins.

MCQ 478

Which of the following combinations contains only acellular infectious agents?

A. Virus, viroid and prion
B. Bacterium, virus and viroid
C. Fungus, virus and prion
D. Protozoan, viroid and virus

Answer: A. Virus, viroid and prion

Explanation: Viruses, viroids and prions lack cellular organisation.

MCQ 479

Which kingdom contains organisms with absorptive heterotrophic nutrition and chitinous cell walls?

A. Monera
B. Protista
C. Fungi
D. Plantae

Answer: C. Fungi

Explanation: These are major distinguishing features of fungi.

MCQ 480

Which pair is INCORRECTLY matched?

A. Diatoms — silica-rich wall
B. Euglenoids — pellicle
C. Cyanobacteria — prokaryotic
D. Fungi — cellulose as the principal wall material

Answer: D. Fungi — cellulose as the principal wall material

Explanation: Fungal cell walls are characteristically rich in chitin rather than cellulose.

---

MCQ 481

Which pair is correctly matched?

A. Halophiles — high salt
B. Methanogens — oxygen-rich habitats
C. Diatoms — chitinous wall
D. Euglenoids — peptidoglycan wall

Answer: A. Halophiles — high salt

Explanation: Halophilic archaea are adapted to highly saline environments.

MCQ 482

Which of the following is a correct difference between diatoms and dinoflagellates?

A. Diatoms have siliceous walls; many dinoflagellates have cellulose plates
B. Both have identical cell coverings
C. Dinoflagellates are prokaryotic
D. Diatoms lack photosynthetic pigments

Answer: A. Diatoms have siliceous walls; many dinoflagellates have cellulose plates

Explanation: Diatoms have silica-containing frustules, while many dinoflagellates have cellulose plates embedded in their cell covering.

MCQ 483

Which protistan group possesses a protein-rich pellicle?

A. Euglenoids
B. Diatoms
C. Slime moulds
D. Sporozoans

Answer: A. Euglenoids

Explanation: Euglenoids have a flexible proteinaceous pellicle.

MCQ 484

Which combination is correctly matched with locomotion?

A. Amoeboid protozoans — pseudopodia
B. Ciliated protozoans — hyphae
C. Flagellated protozoans — frustules
D. Sporozoans — heterocysts

Answer: A. Amoeboid protozoans — pseudopodia

Explanation: Amoeboid protozoans use pseudopodia for locomotion and food capture.

MCQ 485

Which statement about lichens is correct?

A. They are a single photosynthetic organism
B. The fungal partner provides structural support and the photosynthetic partner contributes food
C. Both partners are bacteria
D. They are viruses infecting algae

Answer: B. The fungal partner provides structural support and the photosynthetic partner contributes food

Explanation: Lichens are symbiotic associations between fungi and algae/cyanobacteria.

MCQ 486

Which feature makes lichens particularly sensitive to air pollution?

A. Their dependence on atmospheric substances
B. Their complete absence of metabolism
C. Their ability to produce methane
D. Their bacterial cell wall

Answer: A. Their dependence on atmospheric substances

Explanation: Lichens absorb substances from the atmosphere and are consequently sensitive to pollutants.

MCQ 487

Which one is a mutualistic association rather than a fungal reproductive structure?

A. Mycorrhiza
B. Basidium
C. Ascus
D. Conidiophore

Answer: A. Mycorrhiza

Explanation: Mycorrhiza is a symbiotic association between fungi and plant roots.

MCQ 488

Which of the following represents the correct relationship?

A. Mycobiont — algal partner
B. Phycobiont — fungal partner
C. Mycobiont — fungal partner
D. Phycobiont — bacterial capsule

Answer: C. Mycobiont — fungal partner

Explanation: The fungal component of a lichen is called the mycobiont.

MCQ 489

Which traditional fungal group is characterised by organisms such as Rhizopus?

A. Phycomycetes
B. Basidiomycetes
C. Ascomycetes
D. Deuteromycetes

Answer: A. Phycomycetes

Explanation: In the traditional NCERT classification, Rhizopus is included in Phycomycetes.

MCQ 490

Which of the following is correctly matched?

A. Agaricus — mushroom
B. Puccinia — yeast
C. Saccharomyces — rust
D. Rhizopus — lichen

Answer: A. Agaricus — mushroom

Explanation: Agaricus includes common mushroom species and is traditionally classified among Basidiomycetes.

MCQ 491

Which statement about bacterial endospores is most appropriate?

A. They are the normal reproductive method of all bacteria
B. They can help certain bacteria survive unfavourable conditions
C. They are equivalent to fungal basidiospores
D. They are viral particles

Answer: B. They can help certain bacteria survive unfavourable conditions

Explanation: Certain bacteria form resistant endospores primarily for survival under adverse conditions, rather than as a reproductive mechanism.

MCQ 492

Which bacterial form is comma-shaped?

A. Coccus
B. Bacillus
C. Vibrio
D. Spirillum

Answer: C. Vibrio

Explanation: Vibrios are characteristically comma-shaped bacteria.

MCQ 493

Which bacterial form is spherical?

A. Coccus
B. Bacillus
C. Vibrio
D. Spirillum

Answer: A. Coccus

Explanation: Cocci are spherical or approximately spherical bacteria.

MCQ 494

Which bacterial form is rod-shaped?

A. Bacillus
B. Coccus
C. Vibrio
D. Spirillum

Answer: A. Bacillus

Explanation: Bacilli are rod-shaped bacteria.

MCQ 495

Which bacterial form is typically spiral-shaped?

A. Coccus
B. Bacillus
C. Spirillum
D. Vibrio

Answer: C. Spirillum

Explanation: Spirilla are spiral or helical bacteria.

MCQ 496

Which statement best explains why viruses are described as obligate intracellular parasites?

A. They reproduce only inside suitable living host cells
B. They always live independently in soil
C. They possess their own complete metabolic machinery
D. They can synthesise proteins independently

Answer: A. They reproduce only inside suitable living host cells

Explanation: Viruses depend on the machinery of living host cells for replication.

MCQ 497

Which of the following pairs contains a prokaryote and an acellular entity, respectively?

A. Nostoc and bacteriophage
B. Amoeba and Euglena
C. Agaricus and Rhizopus
D. Diatom and dinoflagellate

Answer: A. Nostoc and bacteriophage

Explanation: Nostoc is a cyanobacterium and hence prokaryotic, whereas a bacteriophage is an acellular virus.

MCQ 498

Which set contains organisms traditionally belonging to three different kingdoms?

A. Nostoc, Amoeba, Rhizopus
B. Amoeba, Euglena, Paramecium
C. Agaricus, Rhizopus, Puccinia
D. Nostoc, Anabaena, Mycoplasma

Answer: A. Nostoc, Amoeba, Rhizopus

Explanation: Nostoc belongs to Monera, Amoeba to Protista, and Rhizopus to Fungi in the traditional five-kingdom system.

MCQ 499

Which combination correctly represents the traditional sequence of major fungal groups discussed in NCERT?

A. Phycomycetes → Ascomycetes → Basidiomycetes → Deuteromycetes
B. Monera → Protista → Fungi → Plantae
C. Ascomycetes → Monera → Basidiomycetes → Protista
D. Deuteromycetes → Monera → Phycomycetes → Plantae

Answer: A. Phycomycetes → Ascomycetes → Basidiomycetes → Deuteromycetes

Explanation: These are the traditional fungal groups covered in the NCERT treatment of Biological Classification.

---

MCQ 500

Which statement provides the most appropriate overall distinction among virus, viroid and prion?

A. Virus = nucleic acid with protein coat; viroid = naked RNA; prion = infectious protein
B. Virus = naked RNA; viroid = protein; prion = DNA
C. Virus = bacteria; viroid = fungus; prion = protozoan
D. All three contain DNA and RNA

Answer: A. Virus = nucleic acid with protein coat; viroid = naked RNA; prion = infectious protein

Explanation: This is the key NCERT-level distinction: viruses contain nucleic acid enclosed in a protein coat, viroids are small naked circular RNA molecules, and prions are infectious proteins.