NEET 2020 Biology Solved Paper

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Q1. The process reponsible for facilitating loss of water in liquid form from the tip of grasss blades at night and in early morning is :
Correct Answer: (c)
Root pressure causes Guttation (loss of water droplets).
Q2. Experimental verification of the chromosomal theory of inheritance was done by:
Correct Answer: (a)
T.H. Morgan experimentally verified the chromosomal theory of inheritance using Drosophila.
Q3. The QRS complex in a standard ECG represents:
Correct Answer: (d)
The QRS complex represents the depolarisation of the ventricles, which initiates ventricular contraction.
Q4. Select the correct statement.
Correct Answer: (b)
Glucocorticoids stimulate gluconeogenesis, lipolysis and proteolysis.
Q5. Bilaterally symmetrical and acoelomate animals are exemplified by:
Correct Answer: (c)
Platyhelminthes (flatworms) are bilaterally symmetrical and acoelomate.
Q6. Which of the following pairs is of unicellular algae?
Correct Answer: (a)
Chlorella and Spirulina are unicellular protein-rich algae.
Q7. Which of the following hormone levels will cause release of ovum (ovulation) from the graffian follicle?
Correct Answer: (b)
High concentration of Estrogen triggers the LH surge, which causes ovulation.
Q8. Match the organism with its use in biotechnology.

OrganismUse
(a) Bacillus thuringiensis(i) Cloning vector
(b) Thermus aquaticus(ii) Construction of first rDNA molecule
(c) Agrobacterium tumefaciens(iii) DNA polymerase
(d) Salmonella typhimurium(iv) Cry proteins
Correct Answer: (c)
Bacillus-Cry proteins(iv), Thermus-DNA polymerase(iii), Agrobacterium-Cloning vector(i), Salmonella-First rDNA(ii).
Q9. Match the following columns and select the correct option.

Column-IColumn-II
(a) Placenta(i) Androgens
(b) Zona pellucida(ii) Human Chorionic Gonadotropin (hCG)
(c) Bulbo-urethral glands(iii) Layer of the ovum
(d) Leydig cells(iv) Lubrication of the Penis
Correct Answer: (b)
Placenta-hCG(ii), Zona-Layer(iii), Bulbo-urethral-Lubrication(iv), Leydig-Androgens(i).
Q10. Which of the following is the most abundant protein in the animals ?
Correct Answer: (c)
Collagen is the most abundant protein in the animal world.
Q11. The infectious stage of Plasmodium that enters the human body is :
Correct Answer: (c)
Sporozoites are the infectious form injected by the mosquito bite.
Q12. The roots that originate from the base of the stem are :
Correct Answer: (b)
Fibrous roots originate from the base of the stem (e.g., in monocots).
Q13. Some dividing cells exit the cell cycle and enter vegetative inactive stage. This is called quiescent stage (G₀). This process occurs at the end of :
Correct Answer: (c)
Cells exit the G1 phase to enter the quiescent stage (G0).
Q14. Match the following columns and select the correct option.

Column - IColumn - II
(a) Clostridium butylicum(i) Cyclosporin - A
(b) Trichoderma polysporum(ii) Butyric Acid
(c) Monascus purpureus(iii) Citric Acid
(d) Aspergillus niger(iv) Blood cholesterol lowering agent
Correct Answer: (c)
Clostridium-Butyric acid(ii), Trichoderma-Cyclosporin A(i), Monascus-Statins(iv), Aspergillus-Citric acid(iii).
Q15. Match the following columns and select the correct option.

Column - IColumn - II
(a) Eosinophils(i) Immune response
(b) Basophils(ii) Phagocytosis
(c) Neutrophils(iii) Release histaminase, destructive enzymes
(d) Lymphocytes(iv) Release granules containing histamine
Correct Answer: (b)
Eosinophils-Histaminase(iii), Basophils-Histamine(iv), Neutrophils-Phagocytosis(ii), Lymphocytes-Immune(i).
Q16. The sequence that controls the copy number of the linked DNA in the vector, is termed :
Correct Answer: (c)
The Origin of Replication (Ori) controls the copy number of the plasmid.
Q17. Identify the correct statement with regard to G₁ phase (Gap 1) of interphase.
Correct Answer: (d)
In G1 phase, the cell is metabolically active and grows continuously but does not replicate its DNA.
Q18. Cuboidal epithelium with brush border of microvilli is found in :
Correct Answer: (d)
PCT of nephron is lined by simple cuboidal brush border epithelium to increase surface area for reabsorption.
Q19. The process of growth is maximum during :
Correct Answer: (b)
Growth is exponential and maximum during the Log (exponential) phase.
Q20. Match the following :

Column IColumn II
(a) Inhibitor of catalytic activity(i) Ricin
(b) Possess peptide bonds(ii) Malonate
(c) Cell wall material in fungi(iii) Chitin
(d) Secondary metabolite(iv) Collagen
Correct Answer: (b)
Inhibitor-Malonate(ii), Peptide bonds-Collagen(iv), Fungal cell wall-Chitin(iii), Secondary metabolite-Ricin(i).
Q21. Which of the following statements are true for the phylum-Chordata ?
(a) In Urochordata notochord extends from head to tail and it is present throughout their life.
(b) In Vertebrata notochord is present during the embryonic period only.
(c) Central nervous system is dorsal and hollow.
(d) Chordata is divided into 3 subphyla : Hemichordata, Tunicata and Cephalochordata.
Choose the correct answer from the options given below:
Correct Answer: (a)
Statement (b) and (c) are true. (a) is false (Urochordata notochord is in tail only). (d) is false (Hemichordata is a separate phylum).
Q22. Match the following with respect to meiosis:

Column IColumn II
(a) Zygotene(i) Terminalization
(b) Pachytene(ii) Chiasmata
(c) Diplotene(iii) Crossing over
(d) Diakinesis(iv) Synapsis
Correct Answer: (c)
Zygotene-Synapsis(iv), Pachytene-Crossing over(iii), Diplotene-Chiasmata(ii), Diakinesis-Terminalization(i).
Q23. Match the following columns and select the correct option.

Column -IColumn -II
(a) 6 -15 pairs of gill slits(i) Trygon
(b) Heterocercal caudal fin(ii) Cyclostomes
(c) Air Bladder(iii) Chondrichthyes
(d) Poison sting(iv) Osteichthyes
Correct Answer: (b)
6-15 pairs gill slits-Cyclostomes(ii), Heterocercal fin-Chondrichthyes(iii), Air Bladder-Osteichthyes(iv), Poison sting-Trygon(i).
Q24. The ovary is half inferior in :
Correct Answer: (a)
Plum, Rose, and Peach have perigynous flowers with a half-inferior ovary.
Q25. Which of the following would help in prevention of diuresis?
Correct Answer: (c)
Aldosterone stimulates reabsorption of Na+ and water from the renal tubules, preventing diuresis (excessive urine loss).
Q26. Which is the important site of formation of glycoproteins and glycolipids in eukaryotic cells ?
Correct Answer: (d)
Golgi bodies are the site of glycosylation, forming glycoproteins and glycolipids.
Q27. Which of the following is not an attribute of a population?
Correct Answer: (a)
Natality, Mortality, and Sex ratio are population attributes. Species interaction is a community-level attribute.
Q28. Identify the wrong statement with reference to immunity.
Correct Answer: (d)
Active immunity is slow and takes time to give its full effective response.
Q29. Which of the following statements is correct ?
Correct Answer: (a)
Adenine pairs with Thymine via 2 Hydrogen bonds. Guanine pairs with Cytosine via 3.
Q30. In relation to Gross primary productivity and Net primary productivity of an ecosystem, which one of the following statements is correct ?
Correct Answer: (c)
GPP = NPP + Respiration. Thus, GPP is always greater than NPP.
Q31. Embryological support for evolution was disapproved by :
Correct Answer: (b)
Karl Ernst von Baer disapproved the embryological support for evolution proposed by Ernst Haeckel, noting that embryos never pass through the adult stages of other animals.
Q32. In gel electrophoresis, separated DNA fragments can be visualized with the help of :
Correct Answer: (c)
DNA fragments are stained with Ethidium bromide and visualized under UV light.
Q33. The enzyme enterokinase helps in conversion of :
Correct Answer: (c)
Enterokinase secreted by intestinal mucosa activates trypsinogen into trypsin.
Q34. Match the following columns and select the correct option.

Column - IColumn - II
(a) Bt cotton(i) Gene therapy
(b) Adenosine deaminase deficiency(ii) Cellular defence
(c) RNAi(iii) Detection of HIV infection
(d) PCR(iv) Bacillus thuringiensis
Correct Answer: (b)
Bt cotton-Bacillus(iv), ADA-Gene therapy(i), RNAi-Cellular defence(ii), PCR-HIV detection(iii).
Q35. Identify the substances having glycosidic bond and peptide bond, respectively in their structure :
Correct Answer: (a)
Inulin is a polysaccharide (glycosidic bond), and Insulin is a protein (peptide bond).
Q36. Identify the incorrect statement.
Correct Answer: (d)
Sapwood is the outer/peripheral secondary xylem, not the innermost.
Q37. Match the following columns and select the correct option.

Column - IColumn - II
(a) Iron(i) Photolysis of water
(b) Zinc(ii) Pollen germination
(c) Boron(iii) Required for chlorophyll biosynthesis
(d) Manganese(iv) IAA biosynthesis
Correct Answer: (d)
Iron-Chlorophyll biosynthesis(iii), Zinc-IAA biosynthesis(iv), Boron-Pollen germination(ii), Manganese-Photolysis(i).
Q38. According to Robert May, the global species diversity is about :
Correct Answer: (a)
Robert May estimated the global species diversity to be about 7 million.
Q39. In light reaction, plastoquinone facilitates the transfer of electrons from :
Correct Answer: (b)
Plastoquinone transports electrons from Photosystem II (PS-II) to the Cytochrome b6f complex.
Q40. Identify the wrong statement with reference to the gene 'I' that controls ABO blood groups.
Correct Answer: (d)
When IA and IB are present, they express **different** sugars (Co-dominance), not the same type.
Q41. The product(s) of reaction catalyzed by nitrogenase in root nodules of leguminous plants is/are :
Correct Answer: (a)
Nitrogenase catalyzes the reduction of nitrogen to ammonia, releasing hydrogen as a by-product (N₂ + 8H⁺ + 8e⁻ → 2NH₃ + H₂).
Q42. The number of substrate level phosphorylations in one turn of citric acid cycle is :
Correct Answer: (c)
There is only one substrate-level phosphorylation (Succinyl-CoA to Succinate) in one turn of the Krebs cycle.
Q43. Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis (Bt) is resistant to :
Correct Answer: (b)
Bt cotton is resistant to insect pests (specifically bollworms).
Q44. Which of the following refer to correct example(s) of organisms which have evolved due to changes in environment brought about by anthropogenic action?
(a) Darwin's Finches of Galapagos islands.
(b) Herbicide resistant weeds.
(c) Drug resistant eukaryotes.
(d) Man-created breeds of domesticated animals like dogs.
Correct Answer: (d)
(b), (c), and (d) are examples of evolution driven by human actions (anthropogenic).
Q45. Match the following columns and select the correct option.

Column-IColumn-II
(a) Gregarious, polyphagous pest(i) Asterias
(b) Adult with radial symmetry and larva with bilateral symmetry(ii) Scorpion
(c) Book lungs(iii) Ctenoplana
(d) Bioluminescence(iv) Locusta
Correct Answer: (c)
Locusta (Pest), Asterias (Echinoderm symmetry), Scorpion (Book lungs), Ctenoplana (Bioluminescence).
Q46. Meiotic division of the secondary oocyte is completed :
Correct Answer: (a)
The secondary oocyte completes Meiosis II only upon entry of the sperm, before nuclei fusion.
Q47. Goblet cells of alimentary canal are modified from :
Correct Answer: (c)
Goblet cells are modified columnar epithelial cells that secrete mucus.
Q48. Match the trophic levels with their correct species examples in grassland ecosystem.

(a) Fourth trophic level(i) Crow
(b) Second trophic level(ii) Vulture
(c) First trophic level(iii) Rabbit
(d) Third trophic level(iv) Grass
Correct Answer: (b)
Fourth-Vulture(ii), Second-Rabbit(iii), First-Grass(iv), Third-Crow(i).
Q49. If the head of cockroach is removed, it may live for few days because:
Correct Answer: (d)
The head contains only a small part of the nervous system; the rest is along the ventral nerve cord.
Q50. Select the correct events that occur during inspiration.
(a) Contraction of diaphragm
(b) Contraction of external inter-costal muscles
(c) Pulmonary volume decreases
(d) Intra pulmonary pressure increases
Correct Answer: (b)
Inspiration involves contraction of diaphragm and external intercostal muscles, increasing pulmonary volume and decreasing pressure.
Q51. Snow-blindness in Antarctic region is due to :
Correct Answer: (c)
UV-B radiation causes inflammation of the cornea known as snow-blindness.
Q52. Which of the following is not an inhibitory substance governing seed dormancy?
Correct Answer: (b)
Gibberellic acid breaks seed dormancy; it is a promoter, not an inhibitor.
Q53. Secondary metabolites such as nicotine, strychnine and caffeine are produced by plants for their :
Correct Answer: (d)
Many secondary metabolites serve as defence mechanisms against grazers and browsers.
Q54. Montreal protocol was signed in 1987 for control of :
Correct Answer: (c)
The Montreal Protocol aims to control the emission of ozone-depleting substances like CFCs.
Q55. The first phase of translation is :
Correct Answer: (d)
The first phase is the charging of tRNA (Aminoacylation).
Q56. If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is 6.6 × 10⁹ bp, then the length of the DNA is approximately :
Correct Answer: (d)
Length = 6.6 x 10^9 x 0.34 x 10^-9 meters ≈ 2.2 meters.
Q57. Choose the correct pair from the following :
Correct Answer: (b)
Ligases join DNA molecules. Exonucleases cut at ends. Polymerases synthesize DNA. Nucleases digest DNA.
Q58. How many true breeding pea plant varieties did Mendel select as pairs, which were similar except in one character with contrasting traits?
Correct Answer: (d)
Mendel selected 14 true-breeding pea plant varieties (7 pairs of contrasting traits).
Q59. From his experiments, S.L. Miller produced amino acids by mixing the following in a closed flask :
Correct Answer: (b)
Miller used Methane (CH4), Hydrogen (H2), Ammonia (NH3) and water vapor at 800°C.
Q60. The transverse section of a plant shows following anatomical features:
(a) Large number of scattered vascular bundles surrounded by bundle sheath.
(b) Large conspicuous parenchymatous ground tissue.
(c) Vascular bundles conjoint and closed.
(d) Phloem parenchyma absent.
Identify the category of plant and its part :-
Correct Answer: (b)
Conjoint, closed, scattered vascular bundles and absence of phloem parenchyma are characteristic features of a Monocotyledonous stem.
Q61. By which method was a new breed 'Hisardale' of sheep formed by using Bikaneri ewes and Marino rams ?
Correct Answer: (d)
Hisardale was developed by Cross breeding Bikaneri ewes and Marino rams.
Q62. In which of the following techniques, the embryos are transferred to assist those females who cannot conceive?
Correct Answer: (b)
Embryo Transfer includes ZIFT (Zygote Intra Fallopian Transfer) and IUT (Intra Uterine Transfer).
Q63. Identify the wrong statement with regard to Restriction Enzymes.
Correct Answer: (a)
While statement (1) is biologically true (Ligases join ends), in the context of 'Restriction Enzymes' features, this is a function of Ligase, not Restriction enzyme. (Official keys often mark this because it describes Ligase, or sometimes the question implies 'Which is not a property of RE?').
Q64. Identify the basic amino acid from the following.
Correct Answer: (d)
Lysine, Arginine, and Histidine are basic amino acids.
Q65. Strobili or cones are found in :
Correct Answer: (a)
Equisetum (Horsetails) possess distinct strobili or cones.
Q66. The plant parts which consist of two generations one within the other :
(a) Pollen grains inside the anther
(b) Germinated pollen grain with two male gametes
(c) Seed inside the fruit
(d) Embryo sac inside the ovule
Correct Answer: (a)
Pollen (gametophyte) in anther (sporophyte) and Embryo sac (gametophyte) in ovule (sporophyte) represent one generation inside another.
Q67. Match the following columns and select the correct option :

Column-IColumn-II
(a) Pituitary gland(i) Grave's disease
(b) Thyroid gland(ii) Diabetes mellitus
(c) Adrenal gland(iii) Diabetes insipidus
(d) Pancreas(iv) Addison's disease
Correct Answer: (b)
Pituitary-Diabetes insipidus(iii), Thyroid-Graves(i), Adrenal-Addison(iv), Pancreas-Diabetes mellitus(ii).
Q68. The specific palindromic sequence which is recognized by EcoRI is :
Correct Answer: (b)
EcoRI recognizes the palindromic sequence 5'-GAATTC-3'.
Q69. Which of the following statements about inclusion bodies is incorrect ?
Correct Answer: (c)
Inclusion bodies are for storage (reserve material), not for ingestion of food particles.
Q70. Ray florets have :
Correct Answer: (b)
Ray florets of sunflower have epigynous flowers with an inferior ovary.
Q71. The body of the ovule is fused within the funicle at:
Correct Answer: (b)
The point of attachment of the body of the ovule to the funicle is called Hilum.
Q72. Flippers of Penguins and Dolphins are examples of:
Correct Answer: (c)
Flippers of Penguins (Birds) and Dolphins (Mammals) are analogous organs resulting from convergent evolution.
Q73. Identify the wrong statement with reference to transport of oxygen.
Correct Answer: (d)
Lower H+ concentration (higher pH) in alveoli favours formation of oxyhaemoglobin. Higher H+ favors dissociation.
Q74. Which of the following statements is not correct?
Correct Answer: (d)
Functional insulin has A and B chains linked together by **disulphide bonds**, not hydrogen bonds.
Q75. In water hyacinth and water lily, pollination takes place by :
Correct Answer: (b)
In aquatic plants like water hyacinth and water lily, flowers emerge above the level of water and are pollinated by insects or wind.
Q76. Floridean starch has structure similar to:
Correct Answer: (c)
Floridean starch (in Red Algae) is structurally very similar to amylopectin and glycogen.
Q77. Identify the correct statement with reference to human digestive system.
Correct Answer: (d)
Ileum is the highly coiled part of the small intestine. Appendix arises from caecum. Serosa is outermost.
Q78. Select the correct match.
Correct Answer: (d)
Sickle cell anaemia is an autosomal recessive disorder caused by a mutation on chromosome 11.
Q79. Which of the following regions of the globe exhibits highest species diversity?
Correct Answer: (a)
The Amazon rain forests in South America have the greatest biodiversity on Earth.
Q80. The oxygenation activity of RuBisCO enzyme in photorespiration leads to the formation of :
Correct Answer: (c)
In photorespiration, RuBisCO binds O₂ producing 1 molecule of Phosphoglycerate (3C) and 1 molecule of Phosphoglycolate (2C).
Q81. Presence of which of the following conditions in urine are indicative of Diabetes Mellitus ?
Correct Answer: (d)
Presence of Ketone bodies (Ketonuria) and Glucose (Glycosuria) in urine indicates Diabetes Mellitus.
Q82. Match the following columns and select the correct option.

Column - IColumn - II
(a) Floating Ribs(i) Located between second and seventh ribs
(b) Acromion(ii) Head of the Humerus
(c) Scapula(iii) Clavicle
(d) Glenoid cavity(iv) Do not connect with the sternum
Correct Answer: (a)
Floating ribs-No sternum connection(iv), Acromion-Articulates with Clavicle(iii), Scapula-2nd to 7th rib(i), Glenoid-Head of Humerus(ii).
Q83. Match the following diseases with the causative organism and select the correct option.

Column - IColumn - II
(a) Typhoid(i) Wuchereria
(b) Pneumonia(ii) Plasmodium
(c) Filariasis(iii) Salmonella
(d) Malaria(iv) Haemophilus
Correct Answer: (c)
Typhoid-Salmonella(iii), Pneumonia-Haemophilus(iv), Filariasis-Wuchereria(i), Malaria-Plasmodium(ii).
Q84. Match the following columns and select the correct option.

Column -IColumn - II
(a) Organ of Corti(i) Connects middle ear and pharynx
(b) Cochlea(ii) Coiled part of the labyrinth
(c) Eustachian tube(iii) Attached to the oval window
(d) Stapes(iv) Located on the basilar membrane
Correct Answer: (d)
Organ of Corti-Basilar membrane(iv), Cochlea-Coiled part(ii), Eustachian tube-Connects middle ear(i), Stapes-Oval window(iii).
Q85. Dissolution of the synaptonemal complex occurs during :
Correct Answer: (d)
The synaptonemal complex dissolves during the Diplotene stage.
Q86. Which of the following is correct about viroids ?
Correct Answer: (c)
Viroids are smaller than viruses and consist of free RNA without a protein coat.
Q87. Name the plant growth regulator which upon spraying on sugarcane crop, increases the length of stem, thus increasing the yield of sugarcane crop.
Correct Answer: (c)
Gibberellins increase the length of internodes in sugarcane.
Q88. Select the option including all sexually transmitted diseases.
Correct Answer: (b)
Gonorrhoea, Syphilis, and Genital herpes are all STDs. Cancer and Malaria are not.
Q89. Name the enzyme that facilitates opening of DNA helix during transcription.
Correct Answer: (a)
During transcription, RNA polymerase binds to the promoter and initiates unwinding (opening) of the DNA helix.
Q90. Which of the following is put into Anaerobic sludge digester for further sewage treatment ?
Correct Answer: (a)
Activated sludge (bacterial flocs) is pumped into anaerobic sludge digesters.

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