NEET Biology Most Important PYQs (Last 10 Years) with Detailed Answers

Biology carries 360 of the 720 total marks in NEET, split evenly between Botany and Zoology. That weighting alone makes it the subject that decides most ranks.

Question patterns in NEET Biology repeat closely from year to year, even when the wording or numbers in a question change. Most questions trace directly to specific lines, diagrams, or examples in the Class 11 and Class 12 NCERT textbooks. This means targeted revision of high-frequency topics, backed by actual past questions, is a more efficient use of time than re-reading the entire syllabus in equal depth.

This guide presents ten verified NEET and AIPMT questions from past papers, spanning Botany and Zoology, each with the original options, the correct answer, and the exact NCERT chapter it draws from. It also covers which chapters repeat most often and the specific wording traps that cost marks even when a student knows the underlying concept.

Previous Year Questions with Answers

1. Photosynthesis in Higher Plants (Botany)

NEET 2017: Phosphoenol pyruvate (PEP) is the primary CO2 acceptor in

1. C4 plants (correct answer)
2. C2 plants
3. C3 and C4 plants
4. C3 plants

PEP is a three-carbon compound present in the mesophyll cell cytoplasm of C4 plants such as maize, sugarcane, and sorghum. The enzyme PEP carboxylase (PEPcase) fixes atmospheric CO2 onto PEP to form oxaloacetic acid (OAA), a four-carbon compound. This initial fixation step in the mesophyll is what distinguishes the C4 pathway from the C3 pathway, where RuBisCO acts directly on CO2 in the mesophyll chloroplasts.

Source: NCERT Class 11 Biology, Chapter: Photosynthesis in Higher Plants.

2. Principles of Inheritance and Variation (Botany)

NEET 2019:In Antirrhinum (Snapdragon), a red flower was crossed with a white flower and in F1 generation, pink flowers were obtained. When pink flowers were selfed, the F2 generation showed white, red and pink flowers. Choose the incorrect statement from the following:

1. Ratio of F2 is 1/4 (Red) : 2/4 (Pink) : 1/4 (White)
2. Law of Segregation does not apply in this experiment (correct answer)
3. This experiment does not follow the Principle of Dominance
4. Pink colour in F1 is due to incomplete dominance

Options A, C, and D are all true statements about this cross and are therefore not the answer, since the question asks for the incorrect one. Incomplete dominance in Antirrhinum produces a 1:2:1 phenotypic ratio in F2, and neither allele fully dominates, so the Principle of Dominance does not hold here. Option B is the incorrect statement, because the Law of Segregation still operates in incomplete dominance: the two alleles for flower colour still separate cleanly during gamete formation. Incomplete dominance affects how the alleles are expressed, not whether they segregate.

Source: NCERT Class 12 Biology, Chapter: Principles of Inheritance and Variation.

3. Molecular Basis of Inheritance (Botany)

NEET 2019: Match the following genes of the Lac operon with their respective products: 

(a) i gene 

(b) z gene 

(c) a gene 

(d) y gene 

 (i) β-galactosidase 

(ii) Permease 

(iii) Repressor 

(iv) Transacetylase. 

Select the correct option.

1. a-iii, b-i, c-ii, d-iv
2. a-iii, b-i, c-iv, d-ii (correct answer)
3. a-i, b-iii, c-ii, d-iv
4. a-i, b-iii, c-iv, d-ii

The i gene is a regulatory gene that codes for the repressor protein, which binds the operator to block transcription in the absence of lactose. The z, y, and a genes are the structural genes of the operon: z codes for β-galactosidase, which hydrolyses lactose into glucose and galactose; y codes for permease, which increases membrane permeability to lactose; and a codes for transacetylase. Students frequently mix up y and a, since both are less emphasised in typical revision compared to z and i.

Source: NCERT Class 12 Biology, Chapter: Molecular Basis of Inheritance.

4. Excretory Products and Their Elimination (Zoology)

AIPMT 2012:The maximum amount of electrolytes and water (70-80 percent) from the glomerular filtrate is reabsorbed in which part of the nephron?

1. Ascending limb of loop of Henle
2. Distal convoluted tubule
3. Proximal convoluted tubule (correct answer)
4. Descending limb of loop of Henle

The proximal convoluted tubule (PCT) is lined with simple cuboidal epithelium bearing a brush border of microvilli, which increases the surface area available for reabsorption. The PCT reabsorbs roughly 70 to 80 percent of the electrolytes and water in the glomerular filtrate, along with nearly all filtered glucose and amino acids. The loop of Henle and distal convoluted tubule handle finer adjustments to urine concentration afterward, but they do not match the PCT's share of total reabsorption.

Source: NCERT Class 11 Biology, Chapter: Excretory Products and their Elimination.

5. Biotechnology and its Applications (Zoology)

NEET 2019:What triggers activation of protoxin to active toxin of Bacillus thuringiensis in bollworm?

1. Acidic pH of stomach
2. Body temperature
3. Moist surface of midgut
4. Alkaline pH of gut (correct answer)

Bacillus thuringiensis produces crystal proteins (Cry proteins) during a specific phase of its growth. Inside the bacterium, this protein remains an inactive protoxin, which is why the bacterium is not harmed by its own toxin. Once an insect ingests the crystals, the alkaline pH of the insect's gut solubilises the crystals and converts the protoxin into its active form. The activated toxin then binds to midgut epithelial cells, creates pores, and causes cell lysis, which kills the insect.

Source: NCERT Class 12 Biology, Chapter: Biotechnology and its Applications.

6. Cell Cycle and Cell Division (Botany)

NEET 2017: Which of the following options gives the correct sequence of events during mitosis?

1. Condensation → nuclear membrane disassembly → crossing over → segregation → telophase
2. Condensation → nuclear membrane disassembly → arrangement at equator → centromere division → segregation → telophase (correct answer)
3. Condensation → crossing over → nuclear membrane disassembly → segregation → telophase
4. Condensation → arrangement at equator → centromere division → segregation → telophase

Options A and C both include "crossing over," which is a meiosis-specific event involving homologous chromosome pairs and does not occur during mitosis. Option D skips nuclear membrane disassembly, an event that occurs in late prophase before chromosomes can move to the metaphase plate. Option B lists every stage in the correct order: chromosome condensation in prophase, nuclear envelope breakdown, alignment at the equatorial plate in metaphase, centromere splitting and segregation in anaphase, and reformation of nuclei in telophase.

Source: NCERT Class 11 Biology, Chapter: Cell Cycle and Cell Division.

7. Biodiversity and Conservation (Botany)

NEET 2020 (Phase 1): Which of the following is the most important cause for animals and plants being driven to extinction?

1. Habitat loss and fragmentation (correct answer)
2. Drought and floods
3. Economic exploitation
4. Alien species invasion

NCERT lists habitat loss and fragmentation as the foremost of the four major causes of biodiversity loss, sometimes referred to together as "the evil quartet" alongside over-exploitation, alien species invasion, and co-extinctions. The textbook's standard example is the shrinking of tropical rainforest cover, which has dropped from roughly 14 percent to about 6 percent of the earth's land surface. The other three options describe real pressures on biodiversity, but none matches the scale of habitat loss.

Source: NCERT Class 12 Biology, Chapter: Biodiversity and Conservation.

8. Animal Kingdom (Zoology)

NEET 2024: Consider the statements: 

A. Annelids are true coelomates. 

B. Poriferans are pseudocoelomates. 

C. Aschelminthes are acoelomates. 

D. Platyhelminthes are pseudocoelomates. 

Choose the correct answer from the options given below.

1. B only
2. A only (correct answer)
3. C only
4. D only

Only statement A is correct. Annelids have a coelom fully lined by mesoderm on both sides, making them true coelomates. Poriferans (sponges) lack true tissues entirely and are not classified by coelom type at all, which makes statement B false. Aschelminthes (roundworms) are pseudocoelomates, not acoelomates, making statement C false. Platyhelminthes (flatworms) are acoelomates, lacking a body cavity altogether, which makes statement D false as written.

Source: NCERT Class 11 Biology, Chapter: Animal Kingdom.

9. Locomotion and Movement (Zoology)

NEET 2021:During muscular contraction which of the following events occur? 

(a) 'H' zone disappears 

(b) 'A' band widens 

(c) 'I' band reduces in width 

(d) Myosin hydrolyzes ATP, releasing the ADP and Pi (e) Z-lines attached to actins are pulled inwards. 

Choose the correct answer from the options given below.

1. (b), (c), (d) and (e) only
2. (b), (d), (e) and (a) only
3. (a), (c), (d) and (e) only (correct answer)
4. (a), (b), (c) and (d) only

During contraction, actin filaments slide over myosin filaments, so the H zone (the region with myosin only) shrinks and disappears, and the I band (actin only) narrows. This rules out statement (b), since the A band, which spans the full length of the myosin filaments, stays the same width throughout contraction; it does not widen. Myosin heads do hydrolyse ATP to power the power stroke, and the Z-lines at each end of the sarcomere are pulled toward the centre as the sarcomere shortens. That leaves (a), (c), (d), and (e) as the correct combination.

Source: NCERT Class 11 Biology, Chapter: Locomotion and Movement.

10. Chemical Coordination and Integration (Zoology)

NEET 2017:Hypersecretion of Growth Hormone in adults does not cause further increase in height, because

1. Growth hormone becomes inactive in adults
2. Muscle fibres do not grow in size after birth
3. Bones lose their sensitivity to Growth Hormone in adults
4. Epiphyseal plates close after adolescence (correct answer)

Growth hormone remains active in adults and continues to influence metabolism; excess secretion in adulthood causes acromegaly, thickening bones and soft tissue rather than lengthening them. Bones do not lose sensitivity to the hormone either. The epiphyseal plates, made of hyaline cartilage at the ends of long bones, are what allow bones to lengthen during childhood and adolescence. Once these plates ossify and close after adolescence, no amount of growth hormone can further increase height, since there is no remaining cartilage to convert into new bone length.

Source: NCERT Class 11 Biology, Chapter: Chemical Coordination and Integration.

NEET Previous Year Question Papers (2013 to 2025)

Practicing NEET previous year question papers is one of the most effective ways to understand the latest exam pattern, chapter-wise weightage, difficulty level, and frequently repeated concepts. Below, you'll find NEET and AIPMT question papers from 2013 to 2025, along with detailed answer keys and solutions to help you analyze your performance and strengthen your preparation.

Chapter-Wise Question Frequency

NTA does not release an official chapter-wise weightage document. The table below reflects a trend-based reading of papers from recent years, and should be treated as a revision guide rather than a guaranteed count for any single upcoming paper.

Common Wording Traps in NEET Biology

NTA rarely tests obscure facts outside the syllabus. Most difficulty comes from close reading rather than depth of knowledge, and the same wording traps repeat across years.

Near-Identical Terms

Renin and rennin are a common example. Renin is a kidney hormone involved in blood pressure regulation. Rennin is a digestive enzyme in an infant's stomach that curdles milk. Misreading one letter under time pressure is enough to lose the mark.

Absolute Qualifiers

Options containing words like always, never, all, or completely deserve close scrutiny, since biology has frequent exceptions. The statement "all chordates have a backbone" is false, since protochordates retain a notochord but never develop a bony vertebral column. By contrast, "all vertebrates are chordates" is true, since Vertebrata is a subphylum within Chordata.

Match-the-Following Questions

When a match-the-following question has four or five pairs, identify the one pair you are certain about first, then eliminate every option that does not contain that pair. This narrows a four-option question to one or two candidates without needing to verify every row.

How Infinity Learn Supports NEET Biology PYQ Practice

• Chapter-Targeted Practice: Filter past questions by chapter immediately after covering that topic in NCERT, rather than waiting to attempt full-length papers.
• Explanation-Based Solutions: Answer keys explain why the correct option holds and why each distractor is wrong, rather than stating the answer alone.
• Timed Practice Sets: Short, chapter-specific tests under exam-length time constraints to build both accuracy and speed.

Conclusion

Genetics, Molecular Biology, Biotechnology, Cell Division, Ecology, Animal Kingdom, Locomotion, and Human Physiology account for the largest share of repeated NEET Biology questions, as reflected in the ten verified questions above. Building consistent accuracy across these areas has a direct, measurable effect on total score.

A workable routine for the final stretch of preparation: read one NCERT chapter closely each morning, then solve the previous 8 to 10 years of questions from that exact chapter in the afternoon under timed conditions. When an answer is wrong, return to the specific NCERT paragraph or diagram involved before moving to the next topic, rather than simply noting the correct option and continuing.