Biology makes up 50% of NEET (360 marks out of 720). This is where NEET is won or lost. Below are the most important NEET Biology questions chapter-wise, based on 10 years of previous year question (PYQ) analysis from 2016–2026.
High-Weightage NEET Biology Chapters (Botany + Zoology)
| Chapter | Class | Average Questions (2016–26) | Marks |
|---|---|---|---|
| Genetics & Molecular Basis of Inheritance | 12 | 15–18 | 60–72 |
| Ecology & Environment | 12 | 10–12 | 40–48 |
| Human Physiology | 11 | 8–10 | 32–40 |
| Plant Physiology | 11 | 7–9 | 28–36 |
| Reproduction | 12 | 8–10 | 32–40 |
| Cell Biology & Cell Division | 11 | 6–8 | 24–32 |
| Evolution | 12 | 4–6 | 16–24 |
| Human Health & Disease | 12 | 4–5 | 16–20 |
| Biotechnology | 12 | 4–5 | 16–20 |
| Structural Organisation in Plants & Animals | 11 | 4–5 | 16–20 |
Chapter-wise Important NEET Biology Questions
1. Cell: The Unit of Life (NEET Weightage: 6–8 marks)
Most Important Topics: Cell organelle functions, differences between prokaryotes & eukaryotes, cell membrane composition, mitosis vs meiosis.
Q1. Which of the following is true about ribosomes?
(a) They are found only in prokaryotes
(b) They are membrane-bound organelles
(c) 80S ribosomes are found in eukaryotic cytoplasm
(d) They synthesize lipids
Answer: (c) — 80S ribosomes are in eukaryotic cytoplasm; 70S in prokaryotes and organelles.
Q2. The middle lamella is composed mainly of:
(a) Cellulose (b) Pectin (c) Lignin (d) Suberin
Answer: (b) — Middle lamella is made of calcium and magnesium pectate (pectin). Directly from NCERT.
Q3. Which organelle is called the “powerhouse of the cell”?
(a) Ribosome (b) Golgi apparatus (c) Mitochondria (d) Lysosome
Answer: (c) — Mitochondria produce ATP via cellular respiration.
2. Genetics & Molecular Basis of Inheritance (15–18 marks — Highest weightage)
Most Important Topics: Mendel’s laws, incomplete dominance, codominance, linkage, crossing over, DNA replication, transcription, translation, genetic code.
Q1. In a dihybrid cross, when F1 heterozygote is selfed, the ratio of phenotype in F2 is:
(a) 1:2:1 (b) 9:3:3:1 (c) 3:1 (d) 1:1:1:1
Answer: (b) — Dihybrid cross F2 phenotype ratio = 9:3:3:1 (law of independent assortment).
Q2. The enzyme responsible for opening the DNA helix during replication is:
(a) DNA polymerase (b) Helicase (c) Ligase (d) Primase
Answer: (b) — Helicase unwinds and separates the two DNA strands. Key NEET fact.
Q3. Which of the following is an example of codominance?
(a) ABO blood groups in humans (b) Skin colour in humans (c) Height in peas (d) Flower colour in Mirabilis
Answer: (a) — In ABO blood groups, IA and IB alleles are both expressed in AB blood type (codominance).
Q4. A triplet of bases in tRNA that is complementary to a codon is called:
(a) Codon (b) Anticodon (c) Intron (d) Exon
Answer: (b) — The anticodon on tRNA is complementary to the mRNA codon. Direct NCERT definition.
3. Human Physiology (8–10 marks)
Most Important Topics: Digestion & absorption, breathing & gas exchange, body fluids & circulation, excretion, locomotion & movement, neural control.
Q1. The blood pressure in the pulmonary artery is:
(a) Equal to aortic pressure (b) Higher than aortic pressure (c) Lower than aortic pressure (d) Zero
Answer: (c) — Pulmonary artery pressure (25/10 mmHg) is much lower than aortic pressure (120/80 mmHg).
Q2. The hormone that stimulates reabsorption of water in the distal tubule and collecting duct is:
(a) Aldosterone (b) ADH (Vasopressin) (c) ANF (d) Renin
Answer: (b) — ADH (Anti-Diuretic Hormone) increases water permeability of DCT and collecting duct.
Q3. Which enzyme converts pepsinogen to pepsin?
(a) Trypsin (b) HCl (c) Enterokinase (d) Pepsin itself
Answer: (b) — HCl in stomach converts pepsinogen to active pepsin (autocatalysis also occurs).
4. Ecology (10–12 marks)
Most Important Topics: Population interactions, ecosystem, nutrient cycling, biodiversity, environmental issues, biomes.
Q1. Which of the following is an example of commensalism?
(a) Mycorrhizae (b) Orchids growing on mango tree (c) Lichen (d) Clownfish and sea anemone
Answer: (b) — Orchids (epiphytes) on mango tree: orchid benefits (support + light), mango is unaffected. Classic commensalism.
Q2. The pyramid of energy is always:
(a) Inverted (b) Upright (c) Spindle-shaped (d) Variable
Answer: (b) — Energy pyramid is always upright because energy decreases at each trophic level (only 10% transferred).
Q3. Which of the following is NOT a greenhouse gas?
(a) CO₂ (b) CH₄ (c) N₂O (d) N₂
Answer: (d) — Nitrogen (N₂) is not a greenhouse gas. CO₂, CH₄, N₂O, O₃, water vapour are greenhouse gases.
5. Plant Physiology (7–9 marks)
Most Important Topics: Photosynthesis, respiration, plant growth regulators, mineral nutrition, transport in plants.
Q1. In the light reactions of photosynthesis, photolysis of water occurs in:
(a) Stroma (b) Thylakoid membrane (c) Lumen of thylakoid (d) Outer membrane of chloroplast
Answer: (c) — Water splitting (photolysis) occurs in the lumen (inside) of the thylakoid membrane.
Q2. Which plant growth regulator is known as the “stress hormone”?
(a) Gibberellin (b) Cytokinin (c) Abscisic acid (ABA) (d) Ethylene
Answer: (c) — ABA is the stress hormone — it closes stomata during drought and induces dormancy.
NEET Biology Preparation Tips
- 📖 NCERT is non-negotiable — Read Class 11 + 12 NCERT Biology at least 3 times. Every diagram, footnote, and table has been tested.
- 🔁 Flashcards for definitions — NEET loves precise definitions. Make flashcards for: organelle functions, hormone names, enzyme names, diseases.
- 📊 Diagrams from NCERT — Draw and redraw: cell organelles, heart structure, nephron, digestive system, nitrogen cycle, DNA replication fork.
- 📝 Solve previous year papers — Solve chapter-wise PYQs from 2016–2026. NEET repeats similar concepts in different question formats.
- ⚡ Assertion-Reason questions — Practice these specifically; NEET has included them in recent years.
Master NEET Biology with NEET Gurukul
Our daily MCQ practice sends 50 NEET-level Biology questions every evening — chapter-wise, with detailed explanations. Our Biology faculty Dr. Abhishek Mishra is an NCERT specialist with 10+ years of NEET coaching experience.