NEET 2021 — Zoology

All 50 Zoology questions we hold from this paper, of the 200 on the site for this sitting — every option and the answer key. 4 marks each, −1 for a wrong answer.

Zoology

45 questions, one correct option each. +4 for a correct answer, −1 for a wrong one, nothing for a blank.

Q1 open Biomolecules · Carbohydrates, lipids, amino acids and proteins

Identify the incorrect pair.

A.Alkaloids – Codeine
B.Toxin – Abrin
C.Lectins – Concanavalin A
D.Drugs – Ricin✓

The worked solution is part of a paid pack.

Q2 open Cell Cycle and Cell Division · Phases of the cell cycle

The fruit fly has 8 chromosomes ( $2 n$ ) in each cell. During interphase of mitosis, if the number of chromosomes at $G_{1}$ phase is 8, what would be the number of chromosomes after S phase?

A.8✓
B.16
C.4
D.32

The worked solution is part of a paid pack.

Q3 open Animal Kingdom · Non-chordates: Porifera to Echinodermata

Match List-I with List-II.

List-I	List-II
(a) Metamerism	(i) Coelenterata
(b) Canal system	(ii) Ctenophora
(c) Comb plates	(iii) Annelida
(d) Cnidoblasts	(iv) Porifera

Choose the correct answer from the options given below:

A.(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)
B.(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
C.(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)✓
D.(a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)

The worked solution is part of a paid pack.

Q4 open Reproductive Health · Population and birth control methods

Match List-I with List-II.

List-I	List-II
(a) Vaults	(i) Entry of sperm through the cervix is blocked
(b) IUDs	(ii) Removal of vas deferens
(c) Vasectomy	(iii) Phagocytosis of sperms within the uterus
(d) Tubectomy	(iv) Removal of fallopian tube

Choose the correct answer from the options given below:

A.(a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)
B.(a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)✓
C.(a)-(ii), (b)-(iv), (c)-(iii), (d)-(i)
D.(a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)

The worked solution is part of a paid pack.

Q5 open Molecular Basis of Inheritance · DNA structure and replication

If adenine makes up 30% of a DNA molecule, what will be the percentage of thymine, guanine and cytosine in it?

A.T : 20; G : 30; C : 20
B.T : 20; G : 20; C : 30
C.T : 30; G : 20; C : 20✓
D.T : 20; G : 25; C : 25

The worked solution is part of a paid pack.

Q6 open Molecular Basis of Inheritance · Transcription, genetic code, translation

Which of the following RNAs is not required for the synthesis of protein?

A.mRNA
B.tRNA
C.rRNA
D.siRNA✓

The worked solution is part of a paid pack.

Q7 open Reproductive Health · Population and birth control methods

Which one of the following is an example of a hormone-releasing IUD?

A.CuT
B.LNG-20✓
C.Cu7
D.Multiload 375

The worked solution is part of a paid pack.

Q8 open

Succus entericus is referred to as:

A.Pancreatic juice
B.Intestinal juice✓
C.Gastric juice
D.Chyme

The worked solution is part of a paid pack.

Q9 open Locomotion and Movement · Disorders

A chronic autoimmune disorder affecting the neuromuscular junction, leading to fatigue, weakening and paralysis of skeletal muscle, is called:

A.Arthritis
B.Muscular dystrophy
C.Myasthenia gravis✓
D.Gout

The worked solution is part of a paid pack.

Q10 open Biotechnology and its Applications · Applications in medicine: insulin, gene therapy, molecular diagnosis

With regard to insulin, choose the correct options.

(a) C-peptide is not present in mature insulin

(b) The insulin produced by rDNA technology has C-peptide

(d) A-peptide and B-peptide of insulin are interconnected by disulphide bridges

Choose the correct answer from the options given below:

A.(b) and (d) only
B.(b) and (c) only
C.(a), (c) and (d) only✓
D.(a) and (d) only

The worked solution is part of a paid pack.

Q11 open The Living World · Taxonomy, nomenclature and taxonomic categories

Which one of the following belongs to the family Muscidae?

A.Firefly
B.Grasshopper
C.Cockroach
D.Housefly✓

The worked solution is part of a paid pack.

Q12 open Molecular Basis of Inheritance · Transcription, genetic code, translation

Which is the only enzyme that has the capability to catalyse initiation, elongation and termination in the process of transcription in prokaryotes?

A.DNA-dependent DNA polymerase
B.DNA-dependent RNA polymerase✓
C.DNA ligase
D.DNase

The worked solution is part of a paid pack.

Q13 open Human Reproduction · Fertilisation, implantation, pregnancy, parturition, lactation

Receptors for sperm binding in mammals are present on the:

A.Corona radiata
B.Vitelline membrane
C.Perivitelline space
D.Zona pellucida✓

The worked solution is part of a paid pack.

Q14 open Cell Cycle and Cell Division · Phases of the cell cycle

The centriole undergoes duplication during:

A.S phase✓
B.Prophase
C.Metaphase
D. $G_{2}$ phase

The worked solution is part of a paid pack.

Q15 open Animal Kingdom · Chordates: Pisces to Mammalia

Which one of the following organisms bears hollow and pneumatic long bones?

A.Neophron✓
B.Hemidactylus
C.Macropus
D.Ornithorhynchus

The worked solution is part of a paid pack.

Q16 open Excretory Products and their Elimination · Urine formation and its regulation

Erythropoietin hormone, which stimulates RBC formation, is produced by:

A.Alpha cells of the pancreas
B.The cells of the rostral adenohypophysis
C.The cells of the bone marrow
D.Juxtaglomerular cells of the kidney✓

The worked solution is part of a paid pack.

Q17 open Animal Kingdom · Non-chordates: Porifera to Echinodermata

Match the following.

List-I	List-II
(a) Physalia	(i) Pearl oyster
(b) Limulus	(ii) Portuguese man of war
(c) Ancylostoma	(iii) Living fossil
(d) Pinctada	(iv) Hookworm

Choose the correct answer from the options given below:

A.(a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)
B.(a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)
C.(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)✓
D.(a)-(i), (b)-(iv), (c)-(iii), (d)-(ii)

The worked solution is part of a paid pack.

Q18 open Biotechnology: Principles and Processes · Processes: cloning, PCR, bioreactors

During the process of gene amplification using PCR, if a very high temperature is not maintained in the beginning, then which of the following steps of PCR will be affected first?

A.Annealing
B.Extension
C.Denaturation✓
D.Ligation

The worked solution is part of a paid pack.

Q19 open Structural Organisation in Animals · Animal tissues

Which of the following statements wrongly represents the nature of smooth muscle?

A.These muscles have no striations
B.They are involuntary muscles
C.Communication among the cells is performed by intercalated discs✓
D.These muscles are present in the wall of blood vessels

The worked solution is part of a paid pack.

Q20 open Cell: The Unit of Life · Cell membrane, cell wall and endomembrane system

The organelles that are included in the endomembrane system are:

A.Endoplasmic reticulum, mitochondria, ribosomes and lysosomes
B.Endoplasmic reticulum, Golgi complex, lysosomes and vacuoles✓
C.Golgi complex, mitochondria, ribosomes and lysosomes
D.Golgi complex, endoplasmic reticulum, mitochondria and lysosomes

The worked solution is part of a paid pack.

Q21 open Microbes in Human Welfare · Microbes in household and industrial products

Match List-I with List-II.

List-I	List-II
(a) Aspergillus niger	(i) Acetic acid
(b) Acetobacter aceti	(ii) Lactic acid
(c) Clostridium butylicum	(iii) Citric acid
(d) Lactobacillus	(iv) Butyric acid

Choose the correct answer from the options given below:

A.(a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)✓
B.(a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
C.(a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)
D.(a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)

The worked solution is part of a paid pack.

Q22 open Biotechnology and its Applications · Applications in medicine: insulin, gene therapy, molecular diagnosis

For effective treatment of a disease, early diagnosis and understanding its pathophysiology is very important. Which of the following molecular diagnostic techniques is very useful for early detection?

A.Western blotting technique
B.Southern blotting technique
C.ELISA technique✓
D.Hybridisation technique

The worked solution is part of a paid pack.

Q23 open

Which of the following characteristics is incorrect with respect to the cockroach?

A.A ring of gastric caeca is present at the junction of the midgut and hindgut✓
B.The hypopharynx lies within the cavity enclosed by the mouth parts
C.In females, the 7th–9th sterna together form a genital pouch
D.The 10th abdominal segment in both sexes bears a pair of anal cerci

The worked solution is part of a paid pack.

Q24 open Body Fluids and Circulation · Blood, blood groups and lymph

Persons with 'AB' blood group are called 'universal recipients'. This is due to:

A.Absence of antigens A and B on the surface of RBCs
B.Absence of antigens A and B in plasma
C.Presence of antibodies anti-A and anti-B on RBCs
D.Absence of antibodies anti-A and anti-B in plasma✓

The worked solution is part of a paid pack.

Q25 open

Dobson units are used to measure the thickness of:

A.CFCs
B.Stratosphere
C.Ozone✓
D.Troposphere

The worked solution is part of a paid pack.

Q26 open Animal Kingdom · Non-chordates: Porifera to Echinodermata

Read the following statements.

(a) Metagenesis is observed in helminths

(b) Echinoderms are triploblastic and coelomate animals

(d) Comb plates present in ctenophores help in digestion

(e) The water vascular system is characteristic of echinoderms

Choose the correct answer from the options given below:

A.(c), (d) and (e) are correct
B.(a), (b) and (c) are correct
C.(a), (d) and (e) are correct
D.(b), (c) and (e) are correct✓

The worked solution is part of a paid pack.

Q27 open Principles of Inheritance and Variation · Sex determination, mutation, genetic disorders

In a cross between a male and a female, both heterozygous for the sickle cell anaemia gene, what percentage of the progeny will be diseased?

A.50%
B.75%
C.25%✓
D.100%

The worked solution is part of a paid pack.

Q28 open Body Fluids and Circulation · Blood, blood groups and lymph

Which enzyme is responsible for the conversion of inactive fibrinogens to fibrins?

A.Thrombin✓
B.Renin
C.Epinephrine
D.Thrombokinase

The worked solution is part of a paid pack.

Q29 open Breathing and Exchange of Gases · Exchange and transport of gases

Select the favourable conditions required for the formation of oxyhaemoglobin at the alveoli.

A.High $p O_{2}$ , low $p C O_{2}$ , less $H^{+}$ , lower temperature✓
B.Low $p O_{2}$ , high $p C O_{2}$ , more $H^{+}$ , higher temperature
C.High $p O_{2}$ , high $p C O_{2}$ , less $H^{+}$ , higher temperature
D.Low $p O_{2}$ , low $p C O_{2}$ , more $H^{+}$ , higher temperature

The worked solution is part of a paid pack.

Q30 open

The sphincter of Oddi is present at the:

A.Ileo-caecal junction
B.Junction of the hepato-pancreatic duct and duodenum✓
C.Gastro-oesophageal junction
D.Junction of jejunum and duodenum

The worked solution is part of a paid pack.

Q31 open Cell Cycle and Cell Division · Meiosis and its significance

Which stage of meiotic prophase shows terminalisation of chiasmata as its distinctive feature?

A.Leptotene
B.Zygotene
C.Diakinesis✓
D.Pachytene

The worked solution is part of a paid pack.

Q32 open

Which of the following is not an objective of biofortification in crops?

A.Improve protein content
B.Improve resistance to diseases✓
C.Improve vitamin content
D.Improve micronutrient and mineral content

The worked solution is part of a paid pack.

Q33 open Breathing and Exchange of Gases · Exchange and transport of gases

The partial pressures (in mm Hg) of oxygen ( $O_{2}$ ) and carbon dioxide ( $C O_{2}$ ) at the alveoli (the site of diffusion) are:

A. $p O_{2}$ = 104 and $p C O_{2}$ = 40✓
B. $p O_{2}$ = 40 and $p C O_{2}$ = 45
C. $p O_{2}$ = 95 and $p C O_{2}$ = 40
D. $p O_{2}$ = 159 and $p C O_{2}$ = 0.3

The worked solution is part of a paid pack.

Q34 open Reproductive Health · MTP, STDs and infertility; ART

Venereal diseases can spread through:

(a) Using sterile needles

(b) Transfusion of blood from an infected person

(d) Kissing

(e) Inheritance

Choose the correct answer from the options given below:

A.(a), (b) and (c) only
B.(b), (c) and (d) only
C.(b) and (c) only✓
D.(a) and (c) only

The worked solution is part of a paid pack.

Q35 open Biotechnology: Principles and Processes · Tools of recombinant DNA technology

A specific recognition sequence identified by endonucleases to make cuts at specific positions within the DNA is:

A.Degenerate primer sequence
B.Okazaki sequences
C.Palindromic nucleotide sequences✓
D.Poly(A) tail sequences

The worked solution is part of a paid pack.

Q36 open Molecular Basis of Inheritance · DNA structure and replication

Which one of the following statements about histones is wrong?

A.Histones are organised to form a unit of 8 molecules
B.The pH of histones is slightly acidic✓
C.Histones are rich in the amino acids lysine and arginine
D.Histones carry a positive charge in the side chain

The worked solution is part of a paid pack.

Q37 open Locomotion and Movement · Skeletal muscle and mechanism of contraction

During muscular contraction, which of the following events occur?

(a) 'H' zone disappears

(b) 'A' band widens

(d) Myosin hydrolyses ATP, releasing the ADP and Pi

(e) Z-lines attached to actins are pulled inwards

Choose the correct answer from the options given below:

A.(a), (c), (d), (e) only✓
B.(a), (b), (c), (d) only
C.(b), (c), (d), (e) only
D.(b), (d), (e), (a) only

The worked solution is part of a paid pack.

Q38 open Locomotion and Movement · Skeletal system and joints

Match List-I with List-II.

List-I	List-II
(a) Scapula	(i) Cartilaginous joints
(b) Cranium	(ii) Flat bone
(c) Sternum	(iii) Fibrous joints
(d) Vertebral column	(iv) Triangular flat bone

Choose the correct answer from the options given below:

A.(a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
B.(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
C.(a)-(iv), (b)-(ii), (c)-(iii), (d)-(i)
D.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)✓

The worked solution is part of a paid pack.

Q39 open Human Reproduction · Fertilisation, implantation, pregnancy, parturition, lactation

Which of these is not an important component of the initiation of parturition in humans?

A.Increase in oestrogen and progesterone ratio
B.Synthesis of prostaglandins
C.Release of oxytocin
D.Release of prolactin✓

The worked solution is part of a paid pack.

Q40 open Breathing and Exchange of Gases · Regulation and disorders

Assertion (A): A person goes to high altitude and experiences 'altitude sickness' with symptoms like breathing difficulty and heart palpitations.

Reason (R): Due to low atmospheric pressure at high altitude, the body does not get sufficient oxygen.

In the light of the above statements, choose the correct answer from the options given below:

A.Both (A) and (R) are true and (R) is the correct explanation of (A)✓
B.Both (A) and (R) are true but (R) is not the correct explanation of (A)
C.(A) is true but (R) is false
D.(A) is false but (R) is true

The worked solution is part of a paid pack.

Q41 open Biomolecules · Carbohydrates, lipids, amino acids and proteins

Following are the statements with reference to 'lipids'.

(a) Lipids having only single bonds are called unsaturated fatty acids

(b) Lecithin is a phospholipid

(d) Palmitic acid has 20 carbon atoms including the carboxyl carbon

(e) Arachidonic acid has 16 carbon atoms

Choose the correct answer from the options given below:

A.(a) and (b) only
B.(c) and (d) only
C.(b) and (c) only✓
D.(b) and (e) only

The worked solution is part of a paid pack.

Q42 open Human Health and Disease · Immunity, vaccination, AIDS, cancer

Adenosine deaminase deficiency results in:

A.Dysfunction of the immune system✓
B.Parkinson's disease
C.Digestive disorder
D.Addison's disease

The worked solution is part of a paid pack.

Q43 open Human Reproduction · Fertilisation, implantation, pregnancy, parturition, lactation

Which of the following secretes the hormone relaxin during the later phase of pregnancy?

A.Graafian follicle
B.Corpus luteum✓
C.Foetus
D.Uterus

The worked solution is part of a paid pack.

Q44 open Structural Organisation in Animals · Animal tissues

Identify the types of cell junctions that help to stop the leakage of substances across a tissue and facilitate communication with neighbouring cells via rapid transfer of ions and molecules.

A.Gap junctions and adhering junctions, respectively
B.Tight junctions and gap junctions, respectively✓
C.Adhering junctions and tight junctions, respectively
D.Adhering junctions and gap junctions, respectively

The worked solution is part of a paid pack.

Q45 open

Which of the following is not a step in multiple ovulation embryo transfer technology (MOET)?

A.The cow is administered a hormone having LH-like activity for superovulation✓
B.The cow yields about 6–8 eggs at a time
C.The cow is fertilised by artificial insemination
D.Fertilised eggs are transferred to surrogate mothers at the 8–32 cell stage

The worked solution is part of a paid pack.

Q46 open Human Health and Disease · Common diseases: pathogens and life cycles

Match List-I with List-II.

List-I	List-II
(a) Filariasis	(i) Haemophilus influenzae
(b) Amoebiasis	(ii) Trichophyton
(c) Pneumonia	(iii) Wuchereria bancrofti
(d) Ringworm	(iv) Entamoeba histolytica

Choose the correct answer from the options given below:

A.(a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)
B.(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)✓
C.(a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)
D.(a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)

The worked solution is part of a paid pack.

Q47 open Organisms and Populations · Organism and its environment; adaptations

Match List-I with List-II.

List-I	List-II
(a) Allen's rule	(i) Kangaroo rat
(b) Physiological adaptation	(ii) Desert lizard
(c) Behavioural adaptation	(iii) Marine fish at depth
(d) Biochemical adaptation	(iv) Polar seal

Choose the correct answer from the options given below:

A.(a)-(iv), (b)-(ii), (c)-(iii), (d)-(i)
B.(a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)
C.(a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)✓
D.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)

The worked solution is part of a paid pack.

Q48 open Evolution · Natural selection, Hardy–Weinberg, adaptive radiation

Match List-I with List-II.

List-I	List-II
(a) Adaptive radiation	(i) Selection of resistant varieties due to excessive use of herbicides and pesticides
(b) Convergent evolution	(ii) Bones of forelimbs in man and whale
(c) Divergent evolution	(iii) Wings of butterfly and bird
(d) Evolution by anthropogenic action	(iv) Darwin's finches

Choose the correct answer from the options given below:

A.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)✓
B.(a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
C.(a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)
D.(a)-(i), (b)-(iv), (c)-(iii), (d)-(ii)

The worked solution is part of a paid pack.

Q49 open Molecular Basis of Inheritance · Transcription, genetic code, translation

Statement I: The codon 'AUG' codes for methionine and phenylalanine.

Statement II: 'AAA' and 'AAG' both codons code for the amino acid lysine.

In the light of the above statements, choose the correct answer from the options given below:

A.Both Statement I and Statement II are true
B.Both Statement I and Statement II are false
C.Statement I is correct but Statement II is false
D.Statement I is incorrect but Statement II is true✓

The worked solution is part of a paid pack.

Q50 open

Following are the statements about the prostomium of the earthworm.

(a) It serves as a covering for the mouth

(b) It helps to open cracks in the soil into which it can crawl

(d) It is the first body segment

Choose the correct answer from the options given below:

A.(a), (b) and (c) are correct✓
B.(a), (b) and (d) are correct
C.(a), (b), (c) and (d) are correct
D.(b) and (c) are correct

The worked solution is part of a paid pack.