NEET Biology — Previous Year Pattern Questions

Cell Biology & Cell Division

Q1. The powerhouse of the cell is:

(a) Nucleus (b) Ribosome (c) Mitochondria (d) Golgi apparatus

Mitochondria produce ATP through oxidative phosphorylation. Have their own DNA (circular, like prokaryotes) — supports endosymbiotic theory.

Q2. During which phase of mitosis do chromosomes align at the cell equator?

(a) Prophase (b) Anaphase (c) Metaphase (d) Telophase

Metaphase: chromosomes at metaphase plate. Spindle fibres attach to centromeres. Best phase for karyotyping — chromosomes most condensed and distinct.

Q3. Which of the following is NOT a function of the smooth endoplasmic reticulum?

(a) Lipid synthesis

(b) Detoxification of drugs

(c) Calcium storage in muscle cells

(d) Protein synthesis

Protein synthesis occurs at ribosomes on rough ER. Smooth ER: lipids, steroids, detox, calcium.

Genetics & Molecular Biology

Q4. In a dihybrid cross between RRYY and rryy (R=round, r=wrinkled, Y=yellow, y=green), what proportion of F2 shows round yellow phenotype?

(a) 9/16 (b) 3/16 (c) 7/16 (d) 1/16

Classic 9:3:3:1 ratio. Round Yellow = 9/16.

Q5. The process of gene expression involves:

(a) Replication → Transcription → Translation

(b) Transcription → Translation

(c) Translation → Transcription

(d) Replication → Translation

DNA → mRNA (Transcription) → Protein (Translation). Replication duplicates DNA, not gene expression.

Q6. Which enzyme is responsible for DNA replication?

(a) RNA polymerase (b) DNA polymerase III (c) Helicase (d) Ligase

DNA polymerase III is the main replication enzyme in prokaryotes. DNA polymerase I replaces RNA primers. Helicase unwinds. Ligase joins Okazaki fragments.

Plant Physiology

Q7. Which plant hormone is responsible for apical dominance?

(a) Auxin (IAA) (b) Cytokinin (c) Gibberellin (d) Ethylene

Auxins produced at apical bud suppress lateral bud growth (apical dominance). Removing apex allows lateral buds to grow (used in pruning/topping plants).

Q8. The site of photosynthesis in plants is:

(a) Mitochondria (b) Chloroplast (c) Nucleus (d) Vacuole

Light reactions in thylakoid membranes. Calvin cycle (dark reactions) in stroma. Chlorophyll a is the primary pigment; Chlorophyll b, carotenoids are accessory.

Human Physiology

Q9. Normal blood pH range is:

(a) 6.8–7.0 (b) 7.35–7.45 (c) 7.8–8.0 (d) 6.5–7.0

pH < 7.35 = acidosis (respiratory or metabolic). pH > 7.45 = alkalosis. Maintained by bicarbonate buffer system.

Q10. The pacemaker of the heart is:

(a) Bundle of His (b) AV node (c) SA node (Sinoatrial node) (d) Purkinje fibres

SA node generates 60-100 impulses/minute. AV node (40-60/min) is backup pacemaker. Purkinje fibres distribute impulse to ventricles.

NEET Biology Chapter Weights

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