BIOLOGY NEET PYQ QUIZ : ALL CHAPTERS

Explanation:
The male gametes are flagellated and require a film of water to reach the female reproductive structure.

Explanation:
In angiosperms, one male gamete fuses with the egg, while the other fuses with the polar nuclei. These are called syngamy and triple fusion, respectively. Together they constitute double fertilisation.

Explanation

Pea is a member of Fabaceae.

Its flower is:

Bisexual

Zygomorphic

Papilionaceous

The characteristic papilionaceous corolla consists of:

Standard + Wings + Keel

Therefore, pea is the correct answer.

Explanation:
Bryophytes are predominantly terrestrial but require water for the movement of male gametes to the female reproductive organ. Hence they are called amphibians of the plant kingdom.

Explanation:
Marchantia reproduces vegetatively by gemmae, which are produced inside gemma cups.

Explanation: Cellulose is a major structural component of plant cell walls, while lignin strengthens many specialised plant cell walls. Chitin is characteristic of fungal cell walls. Peptidoglycan is characteristic of most bacterial cell walls.

Explanation: Intercalary meristems occur at the bases of leaves or internodes in many grasses. They allow rapid regrowth after grazing or cutting. Apical meristems occur at root and shoot tips, whereas lateral meristems increase the girth of stems and roots.

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

Explanation:
Taxonomy traditionally includes identification, nomenclature and classification. Systematics has a broader perspective and attempts to understand diversity and evolutionary relationships among organisms.

Explanation: Malonate resembles succinate structurally and competes for the enzyme's active site. It inhibits the conversion of succinate to fumarate. Increasing substrate concentration can reduce the effect of a reversible competitive inhibitor.

Explanation: The axoneme of a typical motile eukaryotic cilium or flagellum contains nine peripheral microtubule doublets and two central microtubules.

Explanation: Mitochondria and chloroplasts are double-membrane-bound organelles that contain their own DNA and ribosomes. They are considered semiautonomous because they can synthesize some proteins but depend on nuclear genes for many others. Neither is classified as part of the endomembrane system.

Explanation:
Strobili occur in certain pteridophytes such as Selaginella and Equisetum and are also characteristic reproductive structures in gymnosperms.

Explanation: Most bacterial cell walls contain peptidoglycan. Plant cell walls are mainly cellulose-based, fungal cell walls contain chitin, and the plant middle lamella is rich in calcium pectate.

Explanation: One round of DNA replication takes place before meiosis I. Meiosis II follows without another S phase, allowing sister chromatids to separate.

Explanation:

A flower is considered a modified shoot. During floral development:

The shoot apical meristem becomes a floral meristem.

Internodes become condensed.

Floral appendages arise at successive nodes.

Therefore, both statements are correct and the reason explains the assertion. The question is recorded as NEET 2023.

Explanation:
Porphyra belongs to Rhodophyceae. Fucus, Sargassum and Laminaria are brown algae.

Explanation:
Chlorella is a unicellular green alga that is rich in protein and has been investigated as a source of food and nutritional supplements.

Explanation: Cellulose forms long, unbranched chains that provide structural strength to plant cell walls.

Explanation: The tonoplast is the membrane surrounding the vacuole. It regulates the movement of substances into and out of the vacuolar compartment.

Explanation: The active site contains residues that help recognise the substrate and facilitate the reaction.

Explanation: A prosthetic group is a tightly bound non-protein component of an enzyme. Some enzymes require cofactors for catalytic activity, although not all enzymes need an additional cofactor. Therefore, the second statement is incorrect.

Repeated-question note: The cofactor/prosthetic-group concept was tested again in NEET-UG 2024 and NEET-UG 2025, with a related question on the haem prosthetic group in 2025. These are related concepts, not necessarily identical questions.

Explanation: The cis face is generally the receiving side of the Golgi apparatus. The trans face is associated with sorting and dispatching processed materials.

Explanation:
Floridean starch, the reserve food of red algae, is chemically similar to glycogen.

Explanation:
A genus contains one or more closely related species. Therefore, species is more specific and has fewer but more closely shared characteristics.

Hierarchy:

Kingdom
↓
Phylum/Division
↓
Class
↓
Order
↓
Family
↓
Genus
↓
Species

Explanation: The nucleolus is a major site of rRNA synthesis. Centrioles have nine peripheral microtubule triplets in a characteristic arrangement. Leucoplasts store substances such as starch, oils and proteins. The Golgi apparatus participates in glycolipid formation and processing.

Explanation: Cisternae are the flattened membrane-bound sacs of the Golgi apparatus. Cristae are folds of the mitochondrial inner membrane, while thylakoids are membrane compartments in chloroplasts.

Explanation: Parenchyma consists mainly of living cells with relatively thin cell walls. It commonly stores food and water. Depending on its location and specialization, parenchyma can also perform photosynthesis, provide buoyancy, and help in gaseous exchange.

Explanation: Parenchyma generally consists of living cells with thin primary walls. Depending on specialization, it performs storage, photosynthesis, secretion, and other functions. It is not restricted to a single function.

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

Explanation

Pneumatophores are specialized respiratory roots that project above the soil or water surface and facilitate gaseous exchange.

Explanation:
Volvox forms a colony consisting of numerous cells embedded in a gelatinous matrix.

Explanation: These structures coordinate synthesis, modification, packaging, transport and intracellular digestion. Mitochondria, chloroplasts and peroxisomes are not included in the classical NCERT endomembrane system.

Explanation: Homologous chromosomes separate during anaphase I. This leads to the reduction from two chromosome sets to one in the resulting cells.

Explanation: Meristematic cells actively divide and generally contain dense cytoplasm, a prominent nucleus, and little or no large central vacuole. They are responsible for plant growth. Apical meristems increase the length of roots and shoots, while lateral meristems contribute to an increase in girth.

Explanation: Collenchyma is generally composed of living, elongated cells with unevenly thickened walls, particularly at the corners. It provides mechanical strength while allowing flexibility in young stems, petioles, and leaf regions.

Explanation: Lysosomes are surrounded by a single membrane. The nucleus, mitochondria and chloroplasts have double-membrane boundaries.

Explanation:
Ectocarpus has alternating multicellular haploid and diploid phases, whereas Fucus has a predominantly diploid life cycle.

Explanation: The standard NCERT endomembrane system includes the endoplasmic reticulum, Golgi apparatus, lysosomes and vacuoles. Mitochondria, chloroplasts and peroxisomes are excluded because their functions are not coordinated with this system in the same way.

Explanation:

Axile placentation occurs when the ovules are attached to the central axis of a multilocular ovary.

Important examples include:

Tomato

Lemon

China rose

Petunia

Brinjal

Pea has marginal placentation, while mustard has parietal placentation.

Explanation:
Scientific names follow internationally accepted nomenclatural conventions and are generally Latin or Latinised in form.

In a binomial:

First word = Genus
Second word = Specific epithet

Example:

Homo sapiens

Homo → genus

sapiens → specific epithet

Explanation: Xylem parenchyma stores substances such as starch and participates in the lateral or radial movement of water and dissolved substances. Tracheids and vessels are primarily involved in water conduction.

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

Explanation: In sucrose, the anomeric carbons of glucose and fructose are involved in the glycosidic bond. It therefore lacks a free anomeric carbon for the usual reducing-sugar reaction.

Explanation: The apical meristem occurs at the growing tips of roots and shoots. Its cell divisions contribute to primary growth, increasing the length of the plant. Vascular cambium and cork cambium are lateral meristems associated with secondary growth.

Explanation

The formula represents:

Five united sepals

Papilionaceous corolla

10 stamens arranged 9 + 1

Monocarpellary gynoecium

Therefore, it represents Fabaceae. NCERT Exemplar specifically identifies this floral formula with Fabaceae.

Explanation:
Both gymnosperms and angiosperms have vascular tissues, ovules and seeds. However, angiosperms possess an ovary that encloses the ovules, and the ovary develops into a fruit.

Explanation

Solanaceae flowers are generally:

Pentamerous

Actinomorphic

Bisexual

Hypogynous

The gynoecium is generally bicarpellary and syncarpous, with a superior ovary.

Explanation: The Calvin cycle takes place in the chloroplast stroma. The light-dependent reactions take place in the thylakoid membranes.

Explanation: DNA replication occurs during S phase, doubling the DNA content from 2C to 4C. The DNA content remains 4C during G2.

Explanation

Potato is a stem tuber.

The “eyes” of potato represent buds, confirming its stem nature.

By contrast:

Sweet potato → modified root

Carrot → modified root

Radish → modified root

Explanation: Recombination nodules are protein-containing structures associated with the machinery responsible for genetic recombination during meiosis. Crossing over occurs between non-sister chromatids of homologous chromosomes during pachytene.

This process produces new combinations of genetic material.

NEET takeaway: Recombination nodules are associated with crossing over during pachytene.

Explanation:
Tomato and potato belong to different genera but the same family:

Tomato → Solanum

Potato → Solanum

Important correction: Modern accepted scientific treatment places both tomato and potato in the genus Solanum. Therefore, for the commonly used modern classification, their maximum similarity is at the genus level.

Because some older PYQ databases use older nomenclature/classification for tomato, this question should be handled carefully in an ebook. The underlying NEET concept is that the lower the taxonomic rank, the greater the similarity.

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

Explanation:
The housefly belongs to the family Muscidae.

Its classification includes:

Kingdom — Animalia

Phylum — Arthropoda

Class — Insecta

Order — Diptera

Family — Muscidae

Genus — Musca

Species — Musca domestica

The other insects belong to different families.

Explanation: Mitochondria and chloroplasts possess their own DNA and ribosomes and can divide within cells. However, many of their proteins are encoded by nuclear genes and supplied by the cell.

Explanation

The papilionaceous corolla is characteristic of Fabaceae.

It consists of:

1 standard

2 wings

2 keel petals

The arrangement is associated with vexillary aestivation.

Explanation: Smooth endoplasmic reticulum is involved in lipid synthesis and detoxification of drugs and other substances, particularly in liver cells. Rough ER is associated with the synthesis of many proteins.

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

Explanation: Synapsis is the pairing of homologous chromosomes. It occurs during zygotene, when the synaptonemal complex develops between the homologous chromosomes.

During pachytene, crossing over occurs between non-sister chromatids.

NEET takeaway: Zygotene = synapsis; pachytene = crossing over.

Explanation: Robert Brown described the nucleus in plant cells in 1831. Robert Hooke had earlier observed cork compartments and introduced the term cell.

Explanation: DNA replication occurs during the synthesis (S) phase of interphase. The DNA content doubles, but the chromosome number generally remains unchanged because the replicated sister chromatids remain attached.

NEET takeaway: S phase = DNA synthesis.

Explanation

Solanaceae has a bicarpellary syncarpous ovary.

The ovary is generally bilocular and possesses axile placentation.

Therefore:

Solanaceae → Axile placentation

Explanation:
Ernst Mayr is associated with the biological species concept. Under this concept, a species is generally a group of naturally interbreeding populations that are reproductively isolated from other such groups and produce fertile offspring.

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.

Explanation: Xylem parenchyma consists of living cells and helps store food and other substances. Tracheids, vessels, and most xylem fibres are dead at maturity and have important roles in water conduction or mechanical support.

Explanation: Collenchyma strengthens growing plant organs while retaining flexibility. This is important in young stems and petioles, which need support without becoming excessively rigid.

Explanation

Petunia belongs to Solanaceae.

The characteristic Solanaceae floral features include:

Actinomorphic flower

Bisexual flower

Five united sepals

Five united petals

Five epipetalous stamens

Bicarpellary syncarpous gynoecium

Superior ovary

Axile placentation

Thus, the given floral formula corresponds to Solanaceae → Petunia.

Explanation

Fabaceae generally possesses a monocarpellary superior ovary with marginal placentation.

A useful NEET comparison is:

Fabaceae → Marginal

Solanaceae → Axile

Liliaceae → Axile

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

Explanation

Fabaceae generally possesses 10 stamens arranged as 9 + 1.

Nine stamens are united and one is free. This condition is called diadelphous.

Its anthers are generally dithecous.

Comparison:

Fabaceae → Diadelphous

Solanaceae → Epipetalous

Liliaceae → Epiphyllous

Therefore, option 2 is correct.

Explanation: Cells in G0 have exited the active cell-cycle sequence. Depending on the cell type and physiological conditions, they may remain quiescent temporarily or for extended periods.

Many mature nerve cells remain outside the active cell cycle under normal conditions.

NEET takeaway: G0 is the quiescent state.

Explanation:
Male cones of Pinus are relatively small and produce pollen grains. Female cones are larger and take considerably longer to mature.

Explanation:
The horse belongs to:

Kingdom — Animalia

Phylum — Chordata

Class — Mammalia

Order — Perissodactyla

Family — Equidae

Genus — Equus

Therefore, Perissodactyla is the order.

Explanation: RNA contains ribose, whereas DNA contains deoxyribose.

Explanation: Pairing of homologous chromosomes, called synapsis, is characteristic of prophase I of meiosis. It is not a normal feature of mitosis.

Chromosome condensation, kinetochore attachment, and sister chromatid separation are all associated with mitosis.

NEET takeaway: Synapsis is characteristic of meiosis I, not mitosis.

Explanation:
Living organisms can sense and respond to changes in their environment. This ability is associated with consciousness. Living organisms possess receptors and mechanisms that allow them to perceive environmental stimuli and respond appropriately.

NEET Concept:
Consciousness and response to stimuli are important characteristics of living organisms.

Explanation: The apoenzyme is the protein component. When combined with the required cofactor, it forms the complete holoenzyme.

Explanation: Lysosomal enzymes are synthesized on ribosomes associated with the rough ER and processed and sorted through the endomembrane system. The Golgi apparatus plays an important role in their sorting and delivery.

Explanation:
Living organisms possess metabolism, which includes all the biochemical reactions occurring inside their cells. Growth, reproduction and movement are not individually exclusive characteristics of living organisms. For example, non-living objects may increase in size by accumulation of material, and reproduction is not an essential characteristic of every individual organism.

NEET Concept:
Metabolism is one of the most important distinguishing features of living organisms.

Explanation

The characteristic features of Solanaceae include:

Pentamerous flowers

Actinomorphic symmetry

Bicarpellary syncarpous gynoecium

Superior ovary

Axile placentation

Fruit generally berry or capsule

Therefore, the correct answer is Solanaceae.

Answer: B. Generic name and specific epithet

Explanation:
The binomial name consists of two components:

Generic name + Specific epithet

Example:

Homo sapiens

Homo = generic name

sapiens = specific epithet

The system is associated with Carolus Linnaeus.

Explanation: F₁ particles are associated with ATP synthase complexes on the inner mitochondrial membrane and project towards the matrix. Histones are associated with chromatin, axonemes form the internal structure of cilia and flagella, and plasmodesmata connect adjacent plant cells.

Explanation:

A rhizome is an underground stem. It possesses:

Nodes

Internodes

Scale leaves

Buds

Adventitious roots

Its apical bud does not necessarily remain above the ground. Therefore, statement C is incorrect.

The question is recorded as a NEET 2022 Phase 2 Morphology question.

Explanation:
Pteridophytes possess well-developed vascular tissues but reproduce by spores rather than seeds. Therefore, they are called vascular cryptogams.

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

Explanation: Pili and fimbriae primarily assist attachment to surfaces or other cells. Some specialised pili participate in DNA transfer, and certain pili can contribute to surface-associated movement. Bacterial flagella are the principal locomotory structures in many motile bacteria.

Explanation: Aerenchyma is a specialized form of parenchyma containing conspicuous air spaces. These spaces facilitate gas exchange and help many aquatic plants maintain buoyancy.

Explanation: Vessel elements are elongated cells that usually lose their protoplasts at maturity. Their end walls have perforations, allowing vessel elements to connect and form conduits for water and dissolved minerals. Vessels are particularly characteristic of angiosperms, although they also occur in some other plant groups.

Explanation

The formula indicates:

Actinomorphic flower

Bisexual

Five united sepals

Five united petals

Five stamens

Bicarpellary syncarpous gynoecium

These are characteristic of Solanaceae.

Explanation:
Biosystematics is concerned with studying the diversity of organisms and their comparative and evolutionary relationships. It uses information from several areas, including morphology, cytology, genetics, ecology and evolutionary history.

NEET Concept:
Systematics is broader than simple naming and classification because it also considers evolutionary relationships.

Explanation:

Fabaceae typically possesses 10 stamens arranged as (9)+1, making them diadelphous. The anthers are dithecous.

Solanaceae has epipetalous stamens, whereas Liliaceae has epiphyllous stamens.

Therefore, option B is correct. This exact question is documented as a NEET 2023 question.

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

Explanation: In eukaryotic cells, the enzymes of the Krebs cycle are located primarily in the mitochondrial matrix, with succinate dehydrogenase associated with the inner mitochondrial membrane.

Explanation

Fabaceae has:

One carpel

Monocarpellary gynoecium

Superior ovary

Marginal placentation

This is an important distinction from Solanaceae and Liliaceae.

Explanation:

Thus, marginal placentation in pea is correctly matched. The same set of relationships was tested in the NEET 2026 paper.

Explanation: Smooth ER lacks attached ribosomes and participates in lipid synthesis. Rough ER bears ribosomes and is involved in synthesising proteins destined for secretion, membranes and certain organelles.

Explanation: Basidiomycetes produce basidiospores externally on basidia.

Explanation: DNA replication occurs during S phase. Each chromosome forms two sister chromatids, but the sister chromatids remain attached.

Therefore:

Before S phase: 8 chromosomes and 8 chromatids.

After S phase: 8 chromosomes and 16 chromatids.

The DNA content doubles, but the chromosome number remains eight.

NEET takeaway: DNA replication does not immediately double chromosome number.

Explanation

In the papilionaceous corolla of Fabaceae, the two anterior petals form the keel or carina.

The three components are:

Standard + Wings + Keel

Hence, Fabaceae is correct.

Explanation:
Species is the basic and lowest principal taxonomic category. Other taxonomic categories are generally arranged around species.

Examples:

Mangifera indica — mango

Solanum tuberosum — potato

Panthera leo — lion

NEET Concept:
Species → Genus → Family → Order → Class → Phylum/Division → Kingdom

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

Explanation: Lecithin is a phospholipid and an important component of biological membranes. Its hydrophilic and hydrophobic regions help it participate in membrane structure.

Explanation:

S phase: DNA replication.

G2 phase: Preparation for mitosis, including synthesis of required proteins.

G0 phase: Quiescent state outside the active cell-cycle sequence.

G1 phase: Interval between mitosis and the beginning of DNA replication.

NEET takeaway: G1, S, G2, and G0 have different functions.

Explanation:

Family → Muscidae

Order → Diptera

Class → Insecta

Phylum → Arthropoda

Therefore:

A-III, B-I, C-IV, D-II

Explanation: The mitochondrial inner membrane surrounds the matrix. The matrix contains enzymes involved in the Krebs cycle, mitochondrial DNA and ribosomes. The inner membrane contains components of the electron transport chain and ATP synthase.

Explanation: Parenchyma is a simple permanent tissue made mainly of one type of cell. Collenchyma and sclerenchyma are also simple permanent tissues. Xylem and phloem are complex permanent tissues because each consists of different cell types working together in transport.

Explanation: Glyoxysomes are specialized microbodies that contain enzymes of the glyoxylate cycle. This pathway helps developing seedlings use stored lipids as a source of carbon for carbohydrate production.

Explanation: When the substrate concentration is low, increasing the substrate concentration increases the reaction rate because more substrate molecules bind to the available enzymes.

When the substrate concentration becomes high, most enzyme active sites become occupied. The enzymes become saturated, and the reaction rate approaches its maximum value, called Vmax.

Explanation:
Conifer leaves are generally needle-like and possess a thick cuticle, adaptations that reduce water loss and help them tolerate cold and dry conditions.

Explanation: Adenine and guanine are purines. Cytosine, thymine and uracil are pyrimidines.

Explanation

In Fabaceae, the corolla is papilionaceous and has vexillary aestivation.

The large standard overlaps the two wings, and the wings overlap the keel petals.

Fabaceae → Papilionaceous corolla → Vexillary aestivation

Explanation:
Selaginella produces microspores and megaspores. This condition is called heterospory and represents an important step toward seed habit.

Explanation: Smooth ER participates in lipid metabolism and steroid synthesis. It is prominent in many steroid-producing cells and also contributes to detoxification in certain tissues.

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.

Explanation: Viruses are acellular infectious agents, not cellular organelles. They lack the complete cellular machinery required for independent metabolism and reproduction. Golgi apparatus, lysosomes and mitochondria are cellular organelles.

Explanation: Lyases catalyse the removal or addition of groups without the usual mechanisms of hydrolysis or oxidation. Removal of a group can result in the formation of a double bond.

Explanation: During diakinesis, chromosomes become highly condensed and chiasmata move towards the ends of chromosomes. This movement is known as terminalisation.

Chiasmata become visible during diplotene, whereas their terminalisation is associated with diakinesis.

NEET takeaway: Diplotene = visible chiasmata; diakinesis = terminalisation.

Explanation: Enzymes accelerate reactions by providing a lower-activation-energy pathway. They do not alter the equilibrium constant or remove the need for energy coupling in energetically unfavourable reactions.

Explanation:
The standard taxonomic hierarchy for animals is:

Kingdom → Phylum → Class → Order → Family → Genus → Species

For plants, Division is commonly used instead of Phylum.

Explanation:

Phyllotaxy means the arrangement of leaves on the stem or branches.

The major types are:

Alternate

Opposite

Whorled

The arrangement of flowers is called inflorescence, not phyllotaxy. This question is documented as Re-NEET 2026.

Explanation

Allium belongs to Liliaceae in the traditional NCERT family treatment.

Other pairs are incorrect:

Petunia → Solanaceae

Pea → Fabaceae

Potato → Solanaceae

Explanation: Lipases hydrolyse ester bonds in lipids, nucleases cleave nucleic acids by breaking phosphodiester linkages, proteases hydrolyse peptide bonds, and amylases act on glycosidic bonds in starch.

Explanation: Sclerenchyma cells typically possess thick, lignified secondary walls that provide rigidity and mechanical strength. Many mature sclerenchyma cells are dead at maturity. The tissue includes fibres and sclereids.

Explanation: Primary structure is the amino acid sequence. Secondary structure includes alpha helices and beta sheets. Disulphide bonds can stabilise tertiary structure, and haemoglobin is a familiar example of a protein with quaternary structure.

Explanation: Ribosomes translate the information carried by mRNA into a polypeptide chain. They consist of rRNA and proteins and are not surrounded by a membrane.

Explanation: Ribosomes attached to the cytoplasmic surface of rough ER synthesize many proteins destined for secretion, insertion into membranes or delivery to the endomembrane system.

Explanation: Collenchyma cell walls show uneven thickening at the corners due largely to cellulose, hemicellulose, and pectin. This wall arrangement provides both strength and flexibility. Lignified, rigid walls are characteristic of many sclerenchyma cells.

Explanation: If nuclear division occurs but cytokinesis fails, the cell may retain two nuclei. Depending on subsequent cell-cycle events, this can contribute to an increased chromosome complement.

Failure of cytokinesis is not the same as normal meiosis, which reduces the chromosome-set number.

Explanation

In Opuntia, the stem becomes flattened, green and photosynthetic. Such a modified stem is called a phylloclade.

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

Explanation:

Pachytene: Crossing over occurs.

Metaphase I: Homologous chromosome pairs align at the equator.

Diakinesis: Terminalisation of chiasmata occurs.

Zygotene: Homologous chromosomes pair through synapsis.

NEET takeaway: Learn the sequence of prophase I stages and their defining events.

Explanation:

GLUT-4 transports glucose across cell membranes.

Insulin is a hormone that regulates blood glucose.

Trypsin is a protein-digesting enzyme.

Collagen is a structural protein found in connective tissue.

Explanation

In apple, the fleshy edible portion develops largely from the thalamus, along with contribution from other floral tissues. Therefore, it is classified as an accessory/false fruit.

Explanation

Pea belongs to Fabaceae and possesses a characteristic zygomorphic, papilionaceous flower.

The flower has:

One standard

Two wings

Two keel petals

In contrast, Datura and tomato belong to Solanaceae and have actinomorphic flowers.

Explanation: Glutamic acid and aspartic acid are amino acids. Lecithin is a phospholipid, not a fatty acid. Arachidonic acid and palmitic acid are fatty acids.

Explanation:
Gymnosperm ovules are not enclosed by an ovary. Consequently, fruits are absent.

Explanation:
According to Robert May's estimate discussed in NCERT, the global species diversity is approximately 7 million. Only a fraction of the total number of species has been scientifically described.

NEET Concept:
Remember:

Estimated global species diversity ≈ 7 million

Explanation: Sclereids are a type of sclerenchyma cell. The gritty texture of pear flesh is associated with stone cells, which are sclereids. Their thick walls provide hardness and protection.

Explanation: Permanent tissues develop from meristematic cells through differentiation. Their cells acquire specific structures and functions. Many permanent tissue cells no longer divide, although some living plant cells may retain the capacity to divide under suitable conditions.

Explanation: The kinetochore is a protein structure assembled at the centromeric region of a chromosome. Spindle microtubules attach to kinetochores and help position and separate chromosomes during cell division.

Telomeres are protective structures at chromosome ends and are not the usual attachment sites for spindle microtubules.

NEET takeaway: Spindle microtubules attach to kinetochores.

Explanation: Many secretory proteins enter the ER during synthesis, undergo processing and transport to the Golgi apparatus, and are then packaged into vesicles that deliver them to the plasma membrane for secretion.

Explanation: Sieve-tube elements form conducting tubes in angiosperm phloem. They transport organic substances, especially sucrose, from source regions to sink regions. Companion cells assist sieve-tube elements in their metabolic functioning.

Explanation

Sesbania belongs to Fabaceae.

Other options:

Allium → Liliaceae

Petunia → Solanaceae

Brassica → Brassicaceae

Fabaceae is characterized by a papilionaceous corolla, vexillary aestivation and diadelphous stamens.

Explanation

Pea has a monocarpellary ovary, and the ovules are arranged along the ventral suture. This is marginal placentation.

Pea → Marginal

This concept has appeared repeatedly in NEET-level papers; occurrences are consolidated here rather than repeating essentially identical questions.

Explanation:
Chlamydomonas and Chlorella are unicellular green algae. Spirogyra and Ulothrix are filamentous, while Fucus and Sargassum are multicellular brown algae.

Explanation:
Brown algae store carbohydrates mainly as laminarin and mannitol.

Explanation

The characteristic stamen conditions are:

Therefore, Liliaceae — epiphyllous is correct. NCERT describes the Liliaceae androecium as six stamens arranged in two whorls.

Explanation:

Pisum sativum (pea) belongs to Fabaceae.

Its characteristic features include:

Vexillary aestivation

Papilionaceous corolla

Diadelphous stamens, generally (9)+1

Zygomorphic, bisexual flowers

Therefore, pea is the correct answer.

Explanation:

Solanaceae generally has:

Bisexual flowers

Actinomorphic flowers

Five united sepals

Five epipetalous stamens

Superior ovary

Therefore, statement (d), “ovary is inferior,” is incorrect.

The question is listed for Re-NEET 2026.

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

Explanation: The nucleolus is a region within the nucleus where most ribosomal RNA is produced and ribosomal subunits are assembled.

Explanation: Xylem consists of tracheids, vessels, xylem fibres, and xylem parenchyma. Companion cells are associated with sieve-tube elements in the phloem, where they help maintain their functioning.

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

Explanation

Liliaceae is a monocot family.

Its gynoecium is generally:

Tricarpellary

Syncarpous

Ovary superior

Usually trilocular

Placentation axile

The floral formula contains G(3).

Explanation:
As we move downward through the hierarchy, the number of common characteristics generally increases.

Kingdom → Phylum → Class → Order → Family → Genus → Species

Species is the lowest principal category and therefore contains organisms with the greatest similarity.

Explanation: The synaptonemal complex develops during the pairing of homologous chromosomes. It begins to disassemble during diplotene, when homologous chromosomes start separating but remain connected at chiasmata.

Key point: Diplotene is associated with the dissolution of the synaptonemal complex.

Explanation: The typical motile eukaryotic ciliary or flagellar axoneme contains nine peripheral microtubule doublets and two central microtubules. The basal body generally has nine peripheral triplets.