Biology — NEET Complete Yearwise Papers MCQs with Solutions
Free NEET Complete Yearwise Papers Biology MCQs with step-by-step solutions (90 questions). Part of NEET 2025 Paper. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Biology · medium · theory
The complex II of mitochondrial electron transport chain is also known as
A. Cytochrome bc1
B. Succinate dehydrogenase ✓ Correct
C. Cytochrome c oxidase
D. NADH dehydrogenase
Solution: In the electron transport chain, Complex I is NADH dehydrogenase, Complex II is succinate dehydrogenase (it oxidises succinate from the Krebs cycle and passes electrons to FADH₂/ubiquinone), Complex III is cytochrome bc1 and Complex IV is cytochrome c oxidase.
Q2 — Biology · medium · theory
Polymerase chain reaction (PCR) amplifies DNA following the equation.
A. $N^{2}$
B. $2^{n}$ ✓ Correct
C. $2n + 1$
D. $2N^{2}$
Solution: Each PCR cycle doubles the DNA, so after n cycles the number of copies is $2^{n}$ — about a billion copies after roughly 30 cycles.
Q3 — Biology · medium · theory
What are the potential drawbacks in adoption of the IVF method?
(A) High fatality risk to mother
(B) Expensive instruments and reagents
(C) Husband/wife necessary for being donors
(D) Less adoption of orphans
(E) Not available in India
(F) Possibility that the early embryo does not survive
Choose the correct answer from the options given below:
A. B, D, F only ✓ Correct
B. A, C, D, F only
C. A, B, C, D only
D. A, B, C, E, F only
Solution: IVF is costly (B), its wider use reduces the adoption of orphans (D), and the transferred embryo may fail to survive (F). It carries no high fatality risk to the mother, gamete donors need not be the couple themselves, and the technique is available in India.
Q4 — Biology · medium · theory
What is the name of the blood vessel that carries deoxygenated blood from the body to the heart in a frog?
A. Aorta
B. Pulmonary artery
C. Pulmonary vein
D. Vena cava ✓ Correct
Solution: In the frog the venae cavae (precaval and postcaval veins) collect deoxygenated blood from the body and return it to the right atrium of the heart.
Q5 — Biology · medium · theory
Which one of the following statements refers to Reductionist Biology?
A. Physico-chemical approach to study and understand living organisms. ✓ Correct
B. Physiological approach to study and understand living organisms.
C. Chemical approach to study and understand living organisms.
D. Behavioural approach to study and understand living organisms.
Solution: Reductionist biology explains living processes by breaking organisms down to their physico-chemical components — the physico-chemical approach.
Q6 — Biology · medium · theory
Given below are two statements:
Statement I: In the RNA world, RNA is considered the first genetic material evolved to carry out essential life processes. RNA acts as a genetic material and also as a catalyst for some important biochemical reactions in living systems. Being reactive, RNA is unstable.
Statement II: DNA evolved from RNA and is a more stable genetic material. Its double helical strands being complementary, resist changes by evolving repairing mechanism.
In the light of the above statements, choose the most appropriate answer from the options given below:
A. Both statement I and statement II are correct. ✓ Correct
B. Both statement I and statement II are incorrect.
C. Statement I is correct but statement II is incorrect.
D. Statement I is incorrect but statement II is correct.
Solution: Both statements restate the NCERT account: RNA was the first genetic material and catalyst but is reactive and unstable, while DNA — evolved from RNA — is chemically more stable and, with its complementary double strands, has developed repair mechanisms.
Q7 — Biology · medium · theory
Epiphytes that are growing on a mango branch is an example of which of the following?
A. Commensalism ✓ Correct
B. Mutualism
C. Predation
D. Amensalism
Solution: An epiphyte merely uses the tree for support and space: the epiphyte benefits and the mango tree is neither helped nor harmed — commensalism (+/0).
Q8 — Biology · medium · theory
From the statements given below choose the correct option:
(A) The eukaryotic ribosomes are 80S and prokaryotic ribosomes are 70S.
(B) Each ribosome has two sub-units.
(C) The two subunits of 80S ribosome are 60S and 40S while that of 70S are 50S and 30S.
(D) The two subunits of 80S ribosome are 60S and 20S and that of 70S are 50S and 20S.
(E) The two subunits of 80S ribosome are 60S and 30S and that of 70S are 50S and 30S.
A. A, B, C are true ✓ Correct
B. A, B, D are true
C. A, B, E are true
D. B, D, E are true
Solution: Eukaryotic ribosomes are 80S (subunits 60S + 40S) and prokaryotic ribosomes are 70S (subunits 50S + 30S); every ribosome is built of two subunits. So A, B and C are true.
Q9 — Biology · medium · theory
Which one of the following is an example of ex-situ conservation?
A. National park
B. Wildlife Sanctuary
C. Zoos and botanical gardens ✓ Correct
D. Protected areas
Solution: Ex-situ conservation protects species outside their natural habitat — in zoological parks, botanical gardens, seed banks and the like. National parks, sanctuaries and protected areas conserve species in-situ.
Q10 — Biology · medium · theory
Given below are two statements:
Statement I: The primary source of energy in an ecosystem is solar energy.
Statement II: The rate of production of organic matter during photosynthesis in an ecosystem is called net primary productivity (NPP).
In the light of the above statements, choose the most appropriate answer from the options given below:
A. Both statement I and statement II are correct.
B. Both statement I and statement II are incorrect.
C. Statement I is correct but statement II is incorrect. ✓ Correct
D. Statement I is incorrect but statement II is correct.
Solution: Sunlight is indeed the primary energy source of ecosystems. But the rate of organic-matter production during photosynthesis is GROSS primary productivity; net primary productivity is what remains after the plants' own respiration (NPP = GPP − R). So Statement II is incorrect.
Q11 — Biology · medium · theory
Match List-I with List-II.
List-I: (A) Emphysema (B) Angina Pectoris (C) Glomerulonephritis (D) Tetany
List-II: (I) Rapid spasms in muscle due to low Ca⁺⁺ in body fluid (II) Damaged alveolar walls and decreased respiratory surface (III) Acute chest pain when not enough oxygen is reaching to heart muscle (IV) Inflammation of glomeruli of kidney
Choose the correct answer from the options given below:
A. A-III, B-I, C-IV, D-II
B. A-III, B-I, C-II, D-IV
C. A-II, B-IV, C-III, D-I
D. A-II, B-III, C-IV, D-I ✓ Correct
Solution: Emphysema damages alveolar walls and shrinks the respiratory surface (II); angina pectoris is acute chest pain from poor oxygen supply to heart muscle (III); glomerulonephritis is inflammation of the kidney glomeruli (IV); tetany is rapid muscle spasm from low calcium (I).
Q12 — Biology · medium · theory
Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Both wind and water pollinated flowers are not very colourful and do not produce nectar.
Reason (R): The flowers produce enormous amount of pollen grains in wind and water pollinated flowers.
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 and R is NOT the correct explanation of A. ✓ Correct
C. A is true but R is false.
D. A is false but R is true.
Solution: Abiotically pollinated flowers need no showy petals or nectar since they attract no animals — A is true. They do produce pollen in enormous quantity to offset the chance factor — R is also true — but the large pollen output does not explain WHY the flowers are dull and nectarless, so R is not the explanation of A.
Q13 — Biology · medium · theory
Which of the following is an example of non-distilled alcoholic beverage produced by yeast?
A. Whisky
B. Brandy
C. Beer ✓ Correct
D. Rum
Solution: Wine and beer are produced by yeast fermentation without distillation; whisky, brandy and rum are made by distilling the fermented broth.
Q14 — Biology · medium · theory
Given below are two statements:
Statement I: In a floral formula ⊕ stands for zygomorphic nature of the flower, and G̲ stands for inferior ovary.
Statement II: In a floral formula ⊕ stands for actinomorphic nature of the flower and G̲ stands for superior ovary.
In the light of the above statements, choose the correct answer from the options given below:
A. Both Statement I and Statement II are correct.
B. Both Statement I and Statement II are incorrect.
C. Statement I is correct but Statement II is incorrect.
D. Statement I is incorrect but Statement II is correct. ✓ Correct
Solution: In floral formulae ⊕ denotes an actinomorphic (radially symmetrical) flower — zygomorphy is shown by % — and G with a line below it denotes a superior ovary. Statement II states exactly this, so it is correct and Statement I is wrong.
Q15 — Biology · medium · theory
Streptokinase produced by bacterium Streptococcus is used for
A. Curd production
B. Liver disease treatment
C. Ethanol production
D. Removing clots from blood vessel ✓ Correct
Solution: Streptokinase, obtained from Streptococcus and modified by genetic engineering, is used as a "clot buster" — it dissolves clots in the blood vessels of patients who have had myocardial infarction.
Q16 — Biology · medium · theory
Which chromosome in the human genome has the highest number of genes?
A. Chromosome X
B. Chromosome Y
C. Chromosome 1 ✓ Correct
D. Chromosome 10
Solution: The Human Genome Project found chromosome 1 to carry the most genes (nearly 3000), while the Y chromosome has the fewest (231).
Q17 — Biology · medium · theory
Which of the following statement is correct about location of the male frog copulatory pad?
A. First and Second digit of fore limb
B. First digit of hind limb
C. Second digit of fore limb
D. First digit of the fore limb ✓ Correct
Solution: The male frog bears a copulatory (nuptial) pad on the first digit of each forelimb — one of the features distinguishing it from the female.
Q18 — Biology · medium · theory
Which one of the following phytohormones promotes nutrient mobilization which helps in the delay of leaf senescence in plants?
A. Ethylene
B. Abscisic acid
C. Gibberellin
D. Cytokinin ✓ Correct
Solution: Cytokinins promote nutrient mobilisation towards the leaf, which delays leaf senescence — the basis of the "Richmond–Lang effect".
Q19 — Biology · medium · theory
While trying to find out the characteristic of a newly found animal, a researcher did the histology of adult animal and observed a cavity with presence of mesodermal tissue towards the body wall but no mesodermal tissue was observed towards the alimentary canal. What could be the possible coelome of that animal?
A. Acoelomate
B. Pseudocoelomate ✓ Correct
C. Schizocoelomate
D. Spongocoelomate
Solution: When mesoderm lines the body wall but not the gut, the body cavity is a false coelom — the animal is pseudocoelomate, as in aschelminthes (roundworms).
Q20 — Biology · medium · theory
Match List-I with List-II.
List-I: (A) Head (B) Middle piece (C) Acrosome (D) Tail
List-II: (I) Enzymes (II) Sperm motility (III) Energy (IV) Genetic material
Choose the correct answer from the options given below:
A. A-IV, B-III, C-I, D-II ✓ Correct
B. A-IV, B-III, C-II, D-I
C. A-III, B-IV, C-II, D-I
D. A-III, B-II, C-I, D-IV
Solution: The sperm head holds the haploid nucleus (genetic material), the middle piece is packed with mitochondria that supply energy, the acrosome carries enzymes for penetrating the egg, and the tail provides motility.
Q21 — Biology · medium · theory
Given below are the stages in the life cycle of pteridophytes. Arrange the following stages in the correct sequence.
(A) Prothallus stage
(B) Meiosis in spore mother cells
(C) Fertilization
(D) Formation of archegonia and antheridia in gametophyte.
(E) Transfer of antherozoids to the archegonia in presence of water.
Choose the correct answer from the options given below:
A. B, A, D, E, C ✓ Correct
B. B, A, E, C, D
C. D, E, C, A, B
D. E, D, C, B, A
Solution: Spore mother cells in the sporangia undergo meiosis (B); the spores germinate into the prothallus (A); the prothallus bears archegonia and antheridia (D); antherozoids swim through water to the archegonia (E); and fertilization follows (C).
Q22 — Biology · medium · theory
Cardiac activities of the heart are regulated by:
(A) Nodal tissue
(B) A special neural center in the medulla oblongata
(C) Adrenal medullary hormones
(D) Adrenal cortical hormones
Choose the correct answer from the options given below:
A. A, B and C Only ✓ Correct
B. A, B, C and D
C. A, C and D Only
D. A, B and D Only
Solution: The heart is auto-excitable through its nodal tissue, moderated by the cardiovascular centre in the medulla oblongata and by adrenal medullary hormones (adrenaline/noradrenaline). Adrenal cortical hormones do not regulate cardiac activity.
Q23 — Biology · medium · theory
Which of following organisms cannot fix nitrogen?
(A) Azotobacter (B) Oscillatoria (C) Anabaena (D) Volvox (E) Nostoc
Choose the correct answer from the options given below:
A. A only
B. D only ✓ Correct
C. B only
D. E only
Solution: Azotobacter is a free-living nitrogen fixer and Oscillatoria, Anabaena and Nostoc are nitrogen-fixing cyanobacteria. Volvox is a green alga and cannot fix atmospheric nitrogen.
Q24 — Biology · medium · theory
Given below are two statements:
Statement I: Transfer RNAs and ribosomal RNA do not interact with mRNA.
Statement II: RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence.
In the light of the above statements, choose the most appropriate answer from the options given below:
A. Both Statement I and Statement II are correct
B. Both Statement I and Statement II are incorrect
C. Statement I is correct but Statement II is incorrect
D. Statement I is incorrect but Statement II is correct ✓ Correct
Solution: During translation tRNA anticodons pair with mRNA codons on the ribosome (whose rRNA also contacts the mRNA), so Statement I is wrong. RNA interference as a method of cellular defence occurs in all eukaryotic organisms — Statement II is correct.
Q25 — Biology · medium · theory
In the above represented plasmid an alien piece of DNA is inserted at EcoRI site. Which of the following strategies will be chosen to select the recombinant colonies?
A. Using ampicillin & tetracyclin containing medium plate
B. Blue color colonies will be selected
C. White color colonies will be selected. ✓ Correct
D. Blue color colonies grown on ampicillin plates can be selected.
Solution: The EcoRI site lies within the β-galactosidase gene, so inserting alien DNA inactivates it (insertional inactivation). Recombinant colonies cannot turn the chromogenic substrate blue and therefore appear white — the white colonies are selected.
Q26 — Biology · medium · theory
Which of the following genetically engineered organisms was used by Eli Lilly to prepare human insulin?
A. Bacterium ✓ Correct
B. Yeast
C. Virus
D. Phage
Solution: In 1983 Eli Lilly prepared the two human insulin chains from DNA sequences expressed in plasmids of the bacterium Escherichia coli.
Q27 — Biology · medium · theory
Name the class of enzyme that usually catalyze the following reaction:
$S - G + S' \to S + S' - G$
Where, G → a group other than hydrogen, S → a substrate, S' → another substrate
A. Hydrolase
B. Lyase
C. Transferase ✓ Correct
D. Ligase
Solution: Transferases catalyse the transfer of a group G (other than hydrogen) from one substrate to another — exactly the reaction shown.
Q28 — Biology · medium · theory
Find the statement that is NOT correct with regard to the structure of monocot stem.
A. Hypodermis is parenchymatous ✓ Correct
B. Vascular bundles are scattered.
C. Vascular bundles are conjoint and closed.
D. Phloem parenchyma is absent.
Solution: In a monocot stem the hypodermis is sclerenchymatous, not parenchymatous. The scattered, conjoint, closed vascular bundles and the absence of phloem parenchyma are all genuine monocot features.
Q29 — Biology · medium · theory
The correct sequence of events in the life cycle of bryophytes is
(A) Fusion of antherozoid with egg.
(B) Attachment of gametophyte to substratum.
(C) Reduction division to produce haploid spores.
(D) Formation of sporophyte.
(E) Release of antherozoids into water.
Choose the correct answer from the options given below:
A. D, E, A, C, B
B. B, E, A, C, D
C. B, E, A, D, C ✓ Correct
D. D, E, A, B, C
Solution: The gametophyte first attaches to the substratum (B); antherozoids are released into water (E) and fuse with the egg (A); the zygote grows into the sporophyte (D), whose spore mother cells finally undergo reduction division to form haploid spores (C).
Q30 — Biology · medium · theory
Which are correct:
(A) Computed tomography and magnetic resonance imaging detect cancers of internal organs.
(B) Chemotherapeutics drugs are used to kill non-cancerous cells.
(C) α-interferon activate the cancer patients' immune system and helps in destroying the tumour.
(D) Chemotherapeutic drugs are biological response modifiers.
(E) In the case of leukemia blood cell counts are decreased.
Choose the correct answer from the options given below:
A. B and D only
B. D and E only
C. C and D only
D. A and C only ✓ Correct
Solution: CT and MRI are indeed used to detect internal cancers (A), and α-interferon is the biological response modifier that activates the patient's immune system against the tumour (C). Chemotherapy targets cancerous cells, and leukemia RAISES the blood cell count — so B, D and E are wrong.