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NEET UGC Biology Question Paper for 2023

Biology Solve  Questions Paper 2023

With one of the highest numbers of candidates registered for the NEET 2023 exam, the NEET exam previous year question paper 2023 serves as an essential reference for the medical entrance exams’ current competitive nature.

Question 1

Answer: (1) Both A and R are correct and R is the correct explanation of A

Explanation:

  • Assertion A: True. The first stage of the moss gametophyte is the protonema stage.

  • Reason R: True. The protonema develops directly from the spores produced in the capsule of the sporophyte. The reason correctly explains the assertion.


Question 2

Answer: (3) Synergids, Zygote and Primary endosperm nucleus

Explanation:

  • Synergids: These are haploid cells of the embryo sac (gametophyte).

  • Zygote: Formed by the fusion of a haploid male gamete and a haploid egg cell, making it diploid.

  • Primary Endosperm Nucleus (PEN): Formed by the fusion of a diploid secondary nucleus (fusion of two polar nuclei) with a haploid male gamete, making it triploid.


Question 3

Answer: (4) Active Transport

Explanation:
Active transport is the movement of ions or molecules across a membrane against their concentration gradient (from lower to higher concentration). This process requires energy in the form of ATP.


Question 4

Answer: (1) Insect pollinated plants

Explanation:
Large, colourful, and fragrant flowers with nectar are adaptations to attract biotic pollinators, especially insects. These characteristics are typical of entomophilous (insect-pollinated) plants.


Question 5

Answer: (3) A single gene affecting multiple phenotypic expression

Explanation:
Pleiotropism is a phenomenon where a single gene influences two or more seemingly unrelated phenotypic traits. The gene responsible is called a pleiotropic gene.


Question 6

Answer: (3) Ethylene

Explanation:
The plant hormone ethylene promotes rapid internode and petiole elongation in deep-water rice plants. This helps the plant keep its leaves above the water surface during flooding.


Question 7

Answer: (1) Habitat loss and fragmentation

Explanation:
The “Evil Quartet” comprises the four major causes of biodiversity loss: (i) Habitat loss and fragmentation, (ii) Over-exploitation, (iii) Alien species invasions, and (iv) Co-extinctions. Habitat loss and fragmentation is considered the most important cause driving species to extinction.


Question 8

Answer: (4) Bright orange colour

Explanation:
In gel electrophoresis, DNA fragments are stained with ethidium bromide. When exposed to ultraviolet (UV) radiation, the DNA bands appear as bright orange-coloured bands.


Question 9

Answer: (1) Manganese

Explanation:
Manganese (Mn) is a micronutrient that plays a crucial role in the water-splitting reaction during the light reactions of photosynthesis (photolysis of water), which liberates oxygen.


Question 10

Answer: (4) China rose, Petunia and Lemon

Explanation:
Axile placentation is found in plants like China rose (Hibiscus), Petunia, Tomato, and Lemon. In this type, the ovary is septate, and the ovules are borne on the central axis.


Question 11

Answer: (2) Pachytene

Explanation:
The pachytene stage of prophase I in meiosis is characterized by the appearance of recombination nodules. These nodules are protein complexes where crossing over (genetic recombination) takes place between non-sister chromatids of homologous chromosomes.


Question 12

Answer: (1) 680 nm

Explanation:
Photosystem II (PS II) has a reaction centre chlorophyll a molecule called P680, which has an absorption maximum at 680 nm.


Question 13

Answer: (2) Alfred Hershey and Martha Chase

Explanation:
The unequivocal proof that DNA is the genetic material came from the Hershey and Chase experiment (1952), which used radioactive isotopes to show that DNA, not protein, is the genetic material in bacteriophages.


Question 14

Answer: (2) S phase

Explanation:
In eukaryotes, DNA replication occurs during the S phase (Synthesis phase) of the cell cycle. The G1, G2, and M phases are not primarily for DNA replication.


Question 15

Answer: (2) Dedifferentiation

Explanation:
In tissue culture, leaf mesophyll cells (which are differentiated and have lost the capacity to divide) regain their ability to divide and form a mass of cells called a callus. This phenomenon is known as dedifferentiation.


Question 16

Answer: (3) It does not contain complex helices and hence cannot hold iodine molecules

Explanation:
Cellulose does not give a blue colour with iodine because its glucose units are linked by β-1,4 glycosidic bonds, forming a straight, extended chain without complex helices. Starch gives a blue colour because its helical structure can trap iodine molecules.


Question 17

Answer: (2) Gibberellic Acid

Explanation:
Gibberellins (specifically Gibberellic Acid, GA₃) are known to hasten the maturity period of juvenile conifers, leading to early seed production.


Question 18

Answer: (1) Both Statement I and Statement II are correct

Explanation:

  • Statement I: True. Transpiration can generate significant tension (negative pressure) capable of pulling a column of water over 130 meters high.

  • Statement II: True. Transpiration results in evaporative cooling, which can cool leaf surfaces by 10 to 15 degrees.


Question 19

Answer: (1) Dialephous and Dithecous anthers

Explanation:

  • Fabaceae: Stamens are often diadelphous (fused into two bundles) and have dithecous anthers (two lobes).

  • Solanaceae: Stamens are polyandrous (free), epipetalous (attached to petals), and dithecous.

  • Liliaceae: Stamens are polyandrous, epiphyllous (attached to tepals), and dithecous.


Question 20

Answer: (1) All genes that are expressed as RNA

Explanation:
Expressed Sequence Tags (ESTs) are short sequences of DNA that correspond to all the genes that are being expressed as RNA in a tissue or cell type at a given time.


Question 21

Answer: (1) A, B, C only

Explanation:

  • A: Correct. Detritivores (detrivores) perform fragmentation of detritus.

  • B: Correct. Humus is further degraded by microbes during mineralization.

  • C: Correct. Water-soluble inorganic nutrients are precipitated into the soil by a process called leaching.

  • D: Incorrect. The detritus food chain begins with dead organic matter (detritus), not living organisms.

  • E: Incorrect. Earthworms break down detritus by a process called fragmentation, not catabolism. Catabolism is the breakdown of complex organic compounds by microbes into simpler inorganic substances.


Question 22

Answer: (1) Dobson units

Explanation:
The thickness of the ozone layer in a column of air is measured in Dobson Units (DU).


Question 23

Answer: (1) Both A and R are true and R is the correct explanation of A

Explanation:

  • Assertion A: True. Late wood (autumn wood) has fewer xylem elements and narrower vessels.

  • Reason R: True. The cambium is less active during the winter season.
    The reason correctly explains the assertion, as the reduced activity of the cambium in winter leads to the formation of late wood with fewer and narrower vessels.


Question 24

Answer: (3) Anaphase II

Explanation:
Centromere division (splitting) occurs during anaphase of mitosis and anaphase II of meiosis. In anaphase I, homologous chromosomes separate, but the centromere does not divide.


Question 25

Answer: (2) 18 ATP and 12 NADPH₂

Explanation:
For the synthesis of one molecule of glucose (which requires 6 turns of the Calvin cycle):

  • Each turn fixes 1 CO₂ and requires 3 ATP and 2 NADPH₂.

  • For 6 turns (6 CO₂ → 1 glucose): 6 × 3 = 18 ATP and 6 × 2 = 12 NADPH₂.


Question 26

Answer: (2) 1992

Explanation:
The historic Convention on Biological Diversity, also known as ‘The Earth Summit’, was held in Rio de Janeiro, Brazil, in the year 1992.


Question 27

Answer: (3) Respiratory loss

Explanation:
In the equation GPP – R = NPP:

  • GPP = Gross Primary Productivity

  • NPP = Net Primary Productivity

  • R = Respiratory loss (the energy used by plants for respiration).


Question 28

Answer: (2) DNA

Explanation:
During the isolation of genetic material (DNA) in recombinant DNA technology, the purified DNA is precipitated out by adding chilled ethanol. DNA is insoluble in ethanol and forms a visible precipitate.


Question 29

Answer: (2) Transcription of tRNA, 5S rRNA and snRNA

Explanation:
In eukaryotes, RNA polymerase III is responsible for transcribing tRNA, 5S rRNA, and snRNA (small nuclear RNA).


Question 30

Answer: (2) To trap pollen grains

Explanation:
The tassel of a corn cob represents the stigma and style of the female flower. They are long, silky, and feathery, and their function is to wave in the wind to trap pollen grains for pollination.

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Question 31

Answer: (2) Selaginella and Salvinia

Explanation:
Heterosporous pteridophytes produce two different types of spores: microspores and megaspores. Selaginella and Salvinia are examples of heterosporous pteridophytes.


Question 32

Answer: (3) Tungsten or gold

Explanation:
In the gene gun (biolistic) method, microparticles of tungsten or gold are used. These inert metals are coated with the foreign DNA and then bombarded into the host cells.


Question 33

Answer: (4) Statement I is incorrect but Statement II is true

Explanation:

  • Statement I: Incorrect. Endarch and exarch are terms used for describing the position of primary xylem (protoxylem and metaxylem), not secondary xylem.

  • Statement II: True. Exarch condition (where protoxylem is outside and metaxylem is inside) is the most common feature of the root system.


Question 34

Answer: (3) Alfred Sturtevant

Explanation:
Alfred Sturtevant, a student of Thomas Hunt Morgan, used the frequency of recombination between gene pairs on the same chromosome as a measure of the distance between them and created the first genetic map.


Question 35

Answer: (1) Both A and R are true and R is the correct explanation of A

Explanation:

  • Assertion A: True. ATP is used at two steps in glycolysis.

  • Reason R: True. The two steps are the conversion of glucose to glucose-6-phosphate and fructose-6-phosphate to fructose-1,6-bisphosphate. The reason correctly explains the assertion.


Question 36

Answer: (2) Algal blooms caused by excess of organic matter in water improve water quality and promote fisheries

Explanation:
This statement is incorrect. Algal blooms caused by excess nutrients (eutrophication) deteriorate water quality, deplete oxygen, and lead to fish mortality.


Question 37

Answer: (1) 80

Explanation:
A ribosome consists of structural RNAs (rRNAs) and about 80 different proteins.


Question 38

Answer: (3) B and E only

Explanation:

  • B: True. Individuals with Klinefelter’s syndrome (47, XXY) have overall masculine development but some feminine development is also expressed.

  • E: True. Such individuals are sterile.

  • A: Incorrect. Langdon Down described Down’s syndrome, not Klinefelter’s.

  • C: Incorrect. Klinefelter individuals are generally tall, not short-statured.

  • D: Incorrect. Mental retardation is not a typical characteristic.


Question 39

Answer: (The text for this question and its options is missing from the provided document.)


Question 40

Answer: (The text for this question and its options is missing from the provided document.)


Question 41

Answer: (3) A is true but R is false

Explanation:

  • Assertion A: True. In gymnosperms, the pollen grains are released from the microsporangium and are carried by air currents to the ovules.

  • Reason R: False. The pollen tube does not grow through the style and stigma (which are angiosperm structures). In gymnosperms, the pollen tube grows directly towards the archegonia within the ovule.


Question 42

Answer: (1) A – II, B – IV, C – I, D – III

Explanation:

  • Cohesion (A): Mutual attraction among water molecules (II).

  • Adhesion (B): Attraction of water molecules to polar surfaces (IV).

  • Surface Tension (C): Water molecules are more attracted to each other in the liquid phase than to water in the gas phase (I).

  • Guttation (D): Loss of water in the liquid phase (III).


Question 43

Answer: (1) Membrane, proton pump, proton gradient, ATP synthase

Explanation:
Chemiosmosis requires a membrane, a proton pump to create a proton gradient, the proton gradient itself (proton motive force), and ATP synthase to synthesize ATP using the energy from the gradient.


Question 44

Answer: (1) Succinic dehydrogenase

Explanation:
Malonate is a competitive inhibitor of the enzyme succinic dehydrogenase. It resembles the substrate (succinate) in structure and binds to the enzyme’s active site, inhibiting its activity.


Question 45

Answer: (2) A and D only

Explanation:

  • A: True. Lenticels are lens-shaped openings that permit gas exchange.

  • D: True. Bark is a non-technical term that refers to all tissues exterior to the vascular cambium, including the periderm and secondary phloem.

  • B: Incorrect. Bark formed early in the season is called soft bark.

  • C: Incorrect. “Bark” is a non-technical term.

  • E: Incorrect. Phellogen (cork cambium) is a single-layered meristem, but it produces multiple layers of phellem (cork).


Question 46

Answer: (3) A – IV, B – I, C – II, D – III

Explanation:

  • M Phase (A): Equational division (IV).

  • G2 Phase (B): Proteins are synthesized (I) in preparation for mitosis.

  • Quiescent Stage (C): Inactive phase (II) where cells leave the cell cycle.

  • G1 Phase (D): Interval between mitosis and initiation of DNA replication (III).


Question 47

Answer: (2) A – IV, B – I, C – II, D – III

Explanation:

  • Mutualism (A): (+, +) – Both species benefit (IV).

  • Commensalism (B): (+, 0) – One species benefits, the other is unaffected (I).

  • Amensalism (C): (-, 0) – One species is harmed, the other is unaffected (II).

  • Parasitism (D): (+, -) – One species benefits, the other is harmed (III).


Question 48

Answer: (3) Statement I is correct but Statement II is false

Explanation:

  • Statement I: True. This is the correct statement of Gause’s Competitive Exclusion Principle.

  • Statement II: Incorrect. In general, herbivores (and plants) are more adversely affected by competition than carnivores.


Question 49

Answer: (3) A – III, B – I, C – IV, D – II

Explanation:

  • Iron (A): Activator of catalase (III).

  • Zinc (B): Needed in the synthesis of auxin (I).

  • Boron (C): Required for cell elongation and differentiation (IV).

  • Molybdenum (D): Component of nitrate reductase (II).


Question 50

Answer: (1) B, C, D, A

Explanation:
The correct sequence for the formation of recombinant DNA is:

  1. B: Cutting of DNA at a specific location by restriction enzyme.

  2. C: Isolation of the desired DNA fragment.

  3. D: Amplification of the gene of interest using PCR.

  4. A: Insertion of recombinant DNA into the host cell.


Question 51

Answer: (2) A-III, B-IV, C-II, D-I

Explanation:

  • Vasectomy (A): Surgical method (III).

  • Coitus interruptus (B): Natural method (IV).

  • Cervical caps (C): Barrier method (II).

  • Saheli (D): Oral method (I) – a non-steroidal pill.


Question 52

Answer: (1) Both Statement I and Statement II are true

Explanation:

  • Statement I: True. The vas deferens receives a duct from the seminal vesicle and opens into the urethra as the ejaculatory duct.

  • Statement II: True. The cavity of the cervix is called the cervical canal, which along with the vagina forms the birth canal.


Question 53

Answer: (2) Biomagnification refers to increase in concentration of the toxicant at successive trophic levels

Explanation:

  • Statement 2 is correct. Biomagnification is the increase in the concentration of a toxicant at successive trophic levels.

  • Statement 1 is incorrect because eutrophication is the increase in nutrients, not specifically domestic sewage.

  • Statement 3 is incorrect because an excess of nutrients promotes algal blooms.

  • Statement 4 is incorrect because algal blooms increase fish mortality.


Question 54

Answer: (The images for the pedigree symbols are missing from the provided text.)


Question 55

Answer: (2) Gonorrhoea

Explanation:
Gonorrhoea is a sexually transmitted disease (STD) caused by a bacterium (Neisseria gonorrhoeae). Bacterial STDs like gonorrhoea, syphilis, and chlamydia are completely curable if detected early and treated properly. The other options (Genital herpes, Hepatitis-B, HIV) are viral diseases.


Question 56

Answer: (1) A-IV, B-III, C-II, D-I

Explanation:

  • CCK (Cholecystokinin) (A): Acts on the pancreas (IV) to stimulate enzyme secretion.

  • GIP (Gastric Inhibitory Peptide) (B): Acts on the gastric gland (III) to inhibit gastric secretion and motility.

  • ANF (Atrial Natriuretic Factor) (C): Released from the heart (II).

  • ADH (Anti-diuretic Hormone) (D): Acts on the kidney (I) to stimulate water reabsorption.


Question 57

Answer: (2) B, C and D only

Explanation:

  • B: True. ADH facilitates water reabsorption to prevent diuresis.

  • C: True. ANF causes vasodilation.

  • D: True. ADH causes an increase in blood pressure.

  • A: Incorrect. Excessive loss of body fluid switches on osmoreceptors.

  • E: Incorrect. ADH increases GFR (or rather, it increases water reabsorption, which can indirectly affect GFR, but the statement as given is false).


Question 58

Answer: (2) B and C only

Explanation:

  • B: True. The sarcoplasmic reticulum is a storehouse of calcium ions.

  • C: True. The striated appearance is due to the distribution pattern of actin and myosin proteins.

  • A: Incorrect. Muscle bundles (fascicles) are held together by a collagenous tissue layer called fascia, not fascicle. A fascicle is the bundle of muscle fibres itself.

  • D: Incorrect. The functional unit of contraction is the sarcomere, which is the region between two Z-lines, not the M-line.


Question 59

Answer: (1) Helper T-lymphocytes

Explanation:
HIV (Human Immunodeficiency Virus) enters and replicates primarily in helper T-lymphocytes (also called CD4+ T cells). The virus destroys these cells, leading to a weakened immune system.


Question 60

Answer: (2) Hemichordate

Explanation:
Radial symmetry is not found in adults of the phylum Hemichordata. Hemichordates are bilaterally symmetrical. Ctenophores, Coelenterates (Cnidarians), and adult Echinoderms are radially symmetrical.


Question 61

Answer: (3) A is true but R is false

Explanation:

  • Assertion A: True. Nephrons are of two types based on their position: Cortical and Juxtamedullary.

  • Reason R: False. Juxtamedullary nephrons have a long loop of Henle that runs deep into the medulla. Cortical nephrons have a short loop of Henle.


Question 62

Answer: (3) Motility

Explanation:
The cytoskeleton is involved in many functions, including mechanical support, motility (movement), and maintenance of cell shape.


Question 63

Answer: (3) Ileo-caecal valve

Explanation:
The undigested food (faeces) passes from the ileum (the last part of the small intestine) into the caecum (the beginning of the large intestine) through the ileo-caecal valve, which prevents the backflow of the faecal matter.


Question 64

Answer: (The question “Vital capacity of lung is” is incomplete in the provided text. The answer is not given.)


Question 65

Answer: (4) A, C and D only

Explanation:

  • A: True. In non-primate mammals, the cyclical changes during reproduction are called the oestrus cycle.

  • C: True. Lack of menstruation (amenorrhoea) can be indicative of pregnancy.

  • D: True. Cyclic menstruation occurs between menarche and menopause.

  • B: Incorrect. The first menstrual cycle at puberty is called menarche, not menopause. Menopause is the cessation of the menstrual cycle.


Question 66

Answer: (2) Numbat, Spotted cuscus, Flying phalanger

Explanation:
Numbat, spotted cuscus, and flying phalanger are all Australian marsupials that exhibit adaptive radiation. They have evolved from a common ancestor to occupy different ecological niches.


Question 67

Answer: (2) Serum and Urine analysis

Explanation:
Conventional methods like serum and urine analysis are not helpful for early diagnosis of diseases. Techniques like Recombinant DNA Technology, PCR, and ELISA are used for early diagnosis.


Question 68

Answer: (1) Both Statement I and Statement II are true

Explanation:

  • Statement I: True. RNA is unstable and mutates at a faster rate than DNA.

  • Statement II: True. Viruses with RNA genomes and shorter life spans mutate and evolve faster.


Question 69

Answer: (1) A – II, B – III, C – IV, D – I

Explanation:

  • Ringworm (A): Caused by Trichophyton (II).

  • Filariasis (B): Caused by Wuchereria bancrofti (III).

  • Malaria (C): Caused by Plasmodium vivax (IV).

  • Pneumonia (D): Caused by Haemophilus influenzae (I).


Question 70

Answer: (2) Serum and Urine analysis

Explanation:
This is a duplicate of Question 67. Conventional methods like serum and urine analysis do not help in early diagnosis.


Question 71

Answer: (1) A – III, B – I, C – IV, D – II

Explanation:

  • P-wave (A): Depolarisation of atria (III).

  • Q-wave (B): Beginning of systole (I) – Actually, it’s the beginning of ventricular depolarization.

  • QRS complex (C): Depolarisation of ventricles (IV).

  • T-wave (D): Repolarisation of ventricles (II).


Question 72

Answer: (4) A is false but R is true

Explanation:

  • Assertion A: False. Amniocentesis is not a strategy of the Reproductive and Child Health Care (RCH) programme for sex determination. Its use for sex determination is banned in India.

  • Reason R: True. The ban on amniocentesis (for sex determination) helps check the increasing menace of female foeticide.


Question 73

Answer: (2) A – II, B – III, C – IV, D – I

Explanation:
In the lac operon of E. coli:

  • Gene a: Codes for transacetylase (II).

  • Gene y: Codes for permease (III).

  • Gene i: Codes for repressor protein (IV).

  • Gene z: Codes for β-galactosidase (I).


Question 74

Answer: (3) A – III, B – I, C – IV, D – II

Explanation:

  • Peptic cells (A): Secrete proenzyme pepsinogen (III).

  • Goblet cells (B): Secrete mucus (I).

  • Oxyntic cells (C): Secrete HCl and intrinsic factor for absorption of vitamin B₁₂ (IV).

  • Hepatic cells (D): Secrete bile juice (II).


Question 75

Answer: (4) Probe

Explanation:
A probe is not a cloning vector. It is a single-stranded DNA or RNA sequence tagged with a radioactive or fluorescent molecule used to detect a specific gene or sequence. BAC (Bacterial Artificial Chromosome), YAC (Yeast Artificial Chromosome), and pBR322 are all cloning vectors.


Question 76

Answer: (1) A – II, B – I, C – IV, D – III

Explanation:

  • Heroin (A): A depressant that slows down body functions (II).

  • Marijuana (B): Affects the cardiovascular system (I).

  • Cocaine (C): Interferes with the transport of dopamine (IV).

  • Morphine (D): Used as a painkiller (III).


Question 77

Answer: (2) A, C & E only

Explanation:
The endomembrane system includes the Endoplasmic Reticulum (ER), Golgi complex, Lysosomes, and Vacuoles. Mitochondria (A), Chloroplasts (C), and Peroxisomes (E) are not part of this system.


Question 78

Answer: (2) Both A and R are true but R is NOT the correct explanation of A

Explanation:

  • Assertion A: True. Endometrium is necessary for the implantation of the blastocyst.

  • Reason R: True. In the absence of fertilization, the corpus luteum degenerates, leading to the disintegration of the endometrium.
    However, the reason does not explain the assertion. The reason explains menstruation, not the necessity of the endometrium for implantation.


Question 79

Answer: (1) Both Statement I and Statement II are true

Explanation:

  • Statement I: True. Low temperature preserves enzymes in a temporarily inactive state, while high temperature denatures the protein.

  • Statement II: True. This is the correct definition of competitive inhibition.


Question 80

Answer: (3) A – III, B – II, C – IV, D – I

Explanation:

  • Taenia (A – Tapeworm): Flame cells (protonephridia) for excretion (III).

  • Paramoecium (B): Contractile vacuole for osmoregulation and excretion (II).

  • Periplaneta (C – Cockroach): Ureose glands (IV) – actually, malpighian tubules are the main excretory organs in cockroaches.

  • Pheretima (D – Earthworm): Nephridia for excretion (I).


Question 81

Answer: (1) A-I, B-II, C-III, D-IV

Explanation:

  • Leopard and Lion (A): Competition (I).

  • Cuckoo laying eggs in Crow’s nest (B): Brood parasitism (II).

  • Fungi and root of a higher plant in Mycorrhizae (C): Mutualism (III).

  • Cattle egret and Cattle (D): Commensalism (IV).


Question 82

Answer: (4) Statement I is incorrect but Statement II is true

Explanation:

  • Statement I: Incorrect. In prokaryotes, the negatively charged DNA is held with some positively charged proteins in a region called the nucleoid.

  • Statement II: True. In eukaryotes, the negatively charged DNA is wrapped around the positively charged histone octamer to form a nucleosome.


Question 83

Answer: (1) Down syndrome

Explanation:
Broad palm with a single palmar crease (simian crease) is a characteristic symptom of Down syndrome (Trisomy 21).


Question 84

Answer: (2) Hemichordate

Explanation:
This is a duplicate of Question 60. Hemichordates are bilaterally symmetrical animals. Radial symmetry is not found in them.


Question 85

Answer: (1) A-II, B-I, C-III, D-IV

Explanation:

  • Logistic growth (A): Limited resource availability condition (II).

  • Exponential growth (B): Unlimited resource availability condition (I).

  • Expanding age pyramid (C): Pre-reproductive age group is largest, followed by reproductive and post-reproductive (III).

  • Stable age pyramid (D): Pre-reproductive and reproductive age groups are the same (IV).


Question 86

Answer: (2) B and C only

Explanation:
Characteristics of chordates include:

  • B: True. Presence of a closed circulatory system.

  • C: True. Presence of paired pharyngeal gill slits.

  • A: Incorrect. The nerve cord is dorsal, hollow, and single, not solid and double.

  • D: Incorrect. Chordates generally have a ventral heart (except in some), not a dorsal heart.

  • E: Incorrect. Chordates are triploblastic coelomates, not pseudocoelomates.

 

Section

Number of Questions

Marks for Correct Answer

Negative Marking

Total Marks

Physics

45

+4

−1

180

Chemistry

45

+4

−1

180

Biology (Botany + Zoology)

90

+4

−1

360

Total

180

  

720

Question 41

Correct statements about Phaeophyceae:

Answer: (3) A, C, D and E only

Explanation:

  • A is correct: Asexual reproduction by biflagellate zoospores

  • B is incorrect: Sexual reproduction can be oogamous, isogamous, or anisogamous

  • C is correct: Stored food is mannitol or laminarin

  • D is correct: Major pigments: chlorophyll a, c, carotenoids, xanthophylls

  • E is correct: Cellulosic wall covered by gelatinous coating of algin


Question 42

Step in TCA cycle that does NOT involve oxidation:

Answer: (3) Succinyl-CoA → Succinic acid

Explanation:

  • Oxidation involves loss of electrons (increase in oxidation state)

  • Succinyl-CoA → Succinic acid is a hydrolysis reaction (no oxidation)

  • All other options involve oxidation:

    • Malic acid → Oxaloacetic acid (oxidation)

    • Succinic acid → Malic acid (oxidation)

    • Isocitrate → α-ketoglutaric acid (oxidation)


Question 43

Statements about C3 and C4 plants:

Answer: (3) Statement I is true but Statement II is false

Explanation:

  • Statement I is correct: In C3 plants, O₂ competes with CO₂ at RuBisCO (photorespiration), decreasing CO₂ fixation

  • Statement II is false: Photorespiration does NOT occur in C4 plants (they lack RuBisCO in mesophyll cells)


Question 44

Match List I with List II:

 
 
List IList II
A. GLUT-4I. Hormone
B. InsulinII. Enzyme
C. TrypsinIII. Intercellular ground substance
D. CollagenIV. Enables glucose transport into cells

Answer: (1) A-IV, B-I, C-II, D-III

Explanation:

  • GLUT-4: Enables glucose transport into cells (glucose transporter)

  • Insulin: Hormone (regulates blood glucose)

  • Trypsin: Enzyme (digests proteins)

  • Collagen: Intercellular ground substance (structural protein)


Question 45

Match List I with List II:

 
 
List IList II
A. MonoadelphousI. Citrus
B. DiadelphousII. Pea
C. PolyadelphousIII. Lily
D. EpiphyllousIV. China-rose

Answer: (1) A-IV, B-II, C-I, D-III

Explanation:

  • Monoadelphous (stamens united in one bundle) → China-rose

  • Diadelphous (stamens united in two bundles) → Pea

  • Polyadelphous (stamens united in many bundles) → Citrus

  • Epiphyllous (stamens attached to petals) → Lily


Question 46

DNA present in chloroplast is:

Answer: (2) Circular, double stranded

Explanation:

  • Chloroplast DNA is:

    • Circular (not linear)

    • Double-stranded

  • Similar to prokaryotic DNA and mitochondrial DNA

  • This supports the endosymbiotic theory


Question 47

GPP of third trophic level if NPP of first trophic level is 100x:

Answer: (3) 10x (kcal m⁻²) yr⁻¹

Explanation:

  • Only about 10% energy is transferred from one trophic level to next

  • NPP at first trophic level = GPP for second trophic level = 100x

  • NPP at second trophic level = 10% of 100x = 10x = GPP for third trophic level

  • Therefore, GPP of third trophic level = 10x


Question 48

Fused in somatic hybridization:

Answer: (3) Protoplasts

Explanation:

  • Somatic hybridization: Fusion of protoplasts (cells without cell wall) from two different plant varieties/species

  • This produces somatic hybrids

  • Callus: Mass of undifferentiated cells

  • Somatic embryos: Embryos from somatic cells

  • Pollens: Male gametophytes


Question 49

Match List I with List II:

 
 
List IList II
A. Citric acid cycleI. Cytoplasm
B. GlycolysisII. Mitochondrial matrix
C. Electron transport systemIII. Intermembrane space of mitochondria
D. Proton gradientIV. Inner mitochondrial membrane

Answer: (2) A-II, B-I, C-IV, D-III

Explanation:

  • Citric acid cycle → Mitochondrial matrix

  • Glycolysis → Cytoplasm/Cytosol

  • Electron transport system → Inner mitochondrial membrane

  • Proton gradient → Intermembrane space of mitochondria


Question 50

Correct statement about replication in E. coli:

Answer: (4) DNA dependent DNA polymerase catalyses polymerization in 5’→3′ direction

Explanation:

  • DNA polymerase catalyses polymerization in 5’→3′ direction only

  • It cannot polymerize in 3’→5′ direction

  • The enzyme requires a primer to initiate synthesis

  • DNA-dependent RNA polymerase is involved in transcription, not replication


ZOOLOGY SECTION-A

Question 51

Which is not a steroid hormone?

Answer: (4) Glucagon

Explanation:

  • Glucagon is a proteinaceous/peptide hormone secreted by pancreas (alpha cells)

  • Cortisol: Steroid hormone (adrenal cortex)

  • Testosterone: Steroid hormone (testes)

  • Progesterone: Steroid hormone (ovaries)


Question 52

Statements about hymen:

Answer: (3) Statement I is true but Statement II is false

Explanation:

  • Statement I is correct: Presence or absence of hymen is NOT a reliable indicator of virginity

  • Statement II is false: Hymen can be broken by:

    • Sudden jolt

    • Insertion of vaginal tampon

    • Active participation in sports

    • In some women, hymen persists even after coitus


Question 53

Incorrect statement about bioreactors:

Answer: (3) Bio-reactors are used to produce small scale bacterial cultures

Explanation:

  • Bioreactors are used for large volumes (100-1000 litres) of culture

  • Small volumes cannot yield appreciable quantities of products

  • Bioreactors provide optimal growth conditions

  • Most commonly used bioreactors are of stirring type

  • Have agitator system, oxygen delivery system, and foam control system


Question 54

Product of DNA dependent RNA polymerase for given template:

Answer: (1) 5’AUGUACCGUUUUAUGGUUAAGU3′

Explanation:

  • Template: 3’TACATGGCAATATCCATTCAS’

  • mRNA is complementary and antiparallel to template strand

  • RNA polymerase synthesizes mRNA in 5’→3′ direction

  • mRNA sequence: 5’AUGUACCGUUUUAUGGUUAAGU3′

  • Note: In RNA, T is replaced by U


Question 55

Assertion and Reason about FSH:

Answer: (4) A is false but R is true

Explanation:

  • Assertion A is false: FSH acts on ovarian follicles in females, but in males, LH (not FSH) acts on Leydig cells

  • Reason R is true: Growing ovarian follicles secrete estrogen in females; interstitial cells (Leydig) secrete androgens in males

  • LH stimulates Leydig cells to produce testosterone


Question 56

Match List I with List II:

 
 
List IList II
A. TyphoidI. Fungus
B. LeishmaniasisII. Nematode
C. RingwormIII. Protozoa
D. FilariasisIV. Bacteria

Answer: (2) A-IV, B-III, C-I, D-II

Explanation:

  • Typhoid → Bacteria (Salmonella typhimurium)

  • Leishmaniasis → Protozoa (Leishmania donovani)

  • Ringworm → Fungus (Microsporum, Trichophyton, Epidermophyton)

  • Filariasis → Nematode (Wuchereria bancrofti/malayi)


Question 57

Correct pathway of conduction of action potential through heart:

Answer: (1) E-C-A-D-B

Explanation:

  • SA node (E) → AV node (C) → AV bundle (A) → Bundle branches (D) → Purkinje fibres (B)

  • SA node: Pacemaker of heart

  • AV node: Delays impulse slightly

  • AV bundle (Bundle of His): Conducts impulse to ventricles

  • Purkinje fibres: Distribute impulse throughout ventricles


Question 58

Match sub-phases of Prophase I:

 
 
List IList II
A. DiakinesisI. Synaptonemal complex formation
B. PachyteneII. Completion of terminalisation of chiasmata
C. ZygoteneIII. Chromosomes look like thin threads
D. LeptoteneIV. Appearance of recombination nodules

Answer: (3) A-II, B-IV, C-I, D-III

Explanation:

  • Diakinesis: Completion of terminalisation of chiasmata

  • Pachytene: Appearance of recombination nodules (crossing over occurs)

  • Zygotene: Synaptonemal complex formation (pairing of homologous chromosomes)

  • Leptotene: Chromosomes look like thin threads (start condensing)


Question 59

Identify correct matching of muscles with location:

Answer: (2) (a) Skeletal – Triceps, (b) Smooth – Stomach, (c) Cardiac – Heart

Explanation:

  • Figure (a): Skeletal muscle (striated, multinucleated) → Triceps/Biceps

  • Figure (b): Smooth muscle (non-striated, spindle-shaped) → Stomach, intestine, blood vessels

  • Figure (c): Cardiac muscle (striated, branched, intercalated discs) → Heart


Question 60

Match List I with List II:

 
 
List IList II
A. Non-medicated IUDI. Multiload 375
B. Copper releasing IUDII. Progestogens
C. Hormone releasing IUDIII. Lippes loop
D. ImplantsIV. LNG-20

Answer: (4) A-III, B-I, C-IV, D-II

Explanation:

  • Non-medicated IUD: Lippes loop

  • Copper releasing IUD: Multiload 375, Cu-T

  • Hormone releasing IUD: LNG-20 (releases levonorgestrel)

  • Implants: Progestogens (e.g., Norplant)


Question 61

Match List I with List II:

 
 
List IList II
A. LipaseI. Peptide bond
B. NucleaseII. Ester bond
C. ProteaseIII. Glycosidic bond
D. AmylaseIV. Phosphodiester bond

Answer: (3) A-II, B-IV, C-I, D-III

Explanation:

  • Lipase: Breaks ester bonds (in lipids)

  • Nuclease: Breaks phosphodiester bonds (in nucleic acids)

  • Protease: Breaks peptide bonds (in proteins)

  • Amylase: Breaks glycosidic bonds (in carbohydrates/starch)


Question 62

Assertion and Reason about breast-feeding:

Answer: (1) Both A and R are correct and R is the correct explanation of A

Explanation:

  • Assertion A: Breast-feeding during initial period is recommended for healthy baby

  • Reason R: Colostrum contains antibodies essential for developing resistance

  • Colostrum is rich in IgA antibodies (passive immunity)

  • This protects the newborn from infections

  • R correctly explains A


Question 63

Correct sequence of human evolution (Past to Recent):

Answer: (4) A-D-C-B

Explanation:

  • A. Homo habilis (2.4-1.4 mya) → First tool maker

  • D. Homo erectus (1.9-0.1 mya) → First to use fire, migrate

  • C. Homo neanderthalensis (400,000-40,000 years ago)

  • B. Homo sapiens (300,000 years ago to present)


Question 64

Match List I with List II:

 
 
List IList II
A. AxonemeI. Centriole
B. Cartwheel patternII. Cilia and flagella
C. CristaIII. Chromosome
D. SatelliteIV. Mitochondria

Answer: (4) A-II, B-I, C-IV, D-III

Explanation:

  • Axoneme: Found in cilia and flagella (9+2 arrangement of microtubules)

  • Cartwheel pattern: Seen in centrioles (9 triplets arrangement)

  • Crista: Found in mitochondria (inner membrane folds)

  • Satellite: Present in chromosomes (secondary constriction)


Question 65

Match List I with List II:

 
 
List IList II
A. PterophyllumI. Hag fish
B. MyxineII. Saw fish
C. PristisIII. Angel fish
D. ExocoetusIV. Flying fish

Answer: (2) A-III, B-I, C-II, D-IV

Explanation:

  • Pterophyllum → Angel fish (freshwater fish)

  • Myxine → Hag fish (jawless fish)

  • Pristis → Saw fish (cartilaginous fish)

  • Exocoetus → Flying fish (bony fish)


Question 66

Match List I with List II:

 
 
List IList II
A. α-1 antitrypsinI. Cotton bollworm
B. Cry IAbII. ADA deficiency
C. Cry IAcIII. Emphysema
D. Enzyme replacement therapyIV. Corn borer

Answer: (3) A-III, B-IV, C-I, D-II

Explanation:

  • α-1 antitrypsin → Treatment of emphysema

  • Cry IAb gene → Controls corn borer

  • Cry IAc gene → Controls cotton bollworms

  • Enzyme replacement therapy → Treatment option for ADA deficiency


Question 67

“Ti plasmid” of Agrobacterium tumefaciens stands for:

Answer: (3) Tumor inducing plasmid

Explanation:

  • Ti plasmid = Tumor inducing plasmid

  • Contains T-DNA (transfer DNA) which causes tumors in dicot plants

  • Used as a vector in plant genetic engineering

  • Not “tumour inhibiting” or “temperature independent”


Question 68

Match List I with List II:

 
 
List IList II
A. PleurobrachiaI. Mollusca
B. RadulaII. Ctenophora
C. StomochordIII. Osteichthyes
D. Air bladderIV. Hemichordata

Answer: (2) A-II, B-I, C-IV, D-III

Explanation:

  • Pleurobrachia → Phylum Ctenophora (comb jellies)

  • Radula → Phylum Mollusca (rasping feeding organ)

  • Stomochord → Phylum Hemichordata (rudimentary notochord-like structure)

  • Air bladder → Class Osteichthyes (provides buoyancy)


Question 69

Which is not a natural/traditional contraceptive method?

Answer: (4) Vaults

Explanation:

  • Vaults are barrier methods (rubber cap covering cervix)

  • Natural methods include:

    • Coitus interruptus (withdrawal)

    • Periodic abstinence (avoiding coitus during fertile period)

    • Lactational amenorrhea (no ovulation during intense breastfeeding)


Question 70

Correct sequence of stages of cell division:

Answer: (4) E-C-A-D-B

Explanation:

  • E. Gap 1 phase (G₁) → Cell growth

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