Railway exams (RRB-NTPC, Group-D, JE, ALP, Technician, RPF-SI & Constable) test General Science through 8-12 questions drawn from the NCERT syllabus of classes IX & X. Roughly 30% of these are Biology items that reward factual recall rather than deep problem-solving. Typical themes: cell structure, human organ systems, nutrition & health, plant physiology, classification of organisms, common diseases, and environmental issues. A smart strategy is to first master the ultra-frequent “definition & function” facts (e.g., “Which is the largest gland?”, “Photosynthesis occurs in which organelle?”) and then move to assertion-reason or match-the-column type twists.

The weightage pattern shows that roughly 6-8 questions come from Human Physiology, 3-4 from Plants, 2 from Micro-organisms & Health, and 1-2 from Ecology. Diagram-based recall (heart, nephron, chloroplast) and one-liner disease facts (pathogen + vector + affected organ) are favourite examiner picks. Spend 70% of your Biology time on these four blocks; the rest can be covered through previous-year question (PYQ) drills. Below is a 25-MCQ workout graded Easy→Medium→Hard that mirrors the latest shifts in Railway papers. Attempt in 12 min, then review with the given explanations to lock the high-yield facts.

Multiple-Choice Questions

1. Which one of the following is NOT a connective tissue?
   A. Cartilage
   B. Blood
   C. Neuron
   D. Ligament

2. The green pigment essential for photosynthesis is:
   A. Carotene
   B. Xanthophyll
   C. Chlorophyll
   D. Phycobilin

3. Which organelle is called the ‘power-house’ of the cell?
   A. Lysosome
   B. Mitochondrion
   C. Golgi body
   D. Ribosome

4. The disease ‘Goitre’ is caused by the deficiency of:
   A. Iron
   B. Calcium
   C. Iodine
   D. Potassium

5. Which part of the brain controls the heartbeat?
   A. Cerebrum
   B. Medulla oblongata
   C. Cerebellum
   D. Hypothalamus

6. An example of a hereditary disease is:
   A. AIDS
   B. Haemophilia
   C. Typhoid
   D. Malaria

7. The vector of malaria is:
   A. Female Anopheles mosquito
   B. Culex mosquito
   C. Aedes mosquito
   D. Housefly

8. Which one of the following is a micronutrient for plants?
   A. Nitrogen
   B. Phosphorus
   C. Zinc
   D. Carbon

9. The opening between the right atrium and right ventricle is guarded by the:
   A. Mitral valve
   B. Tricuspid valve
   C. Semilunar valve
   D. Bicuspid valve

10. Which of the following is NOT a function of saliva?
    A. Digestion of fat
    B. Digestion of starch
    C. Lubrication of food
    D. Antibacterial action

11. The universal acceptor blood group among humans is:
    A. AB⁺
    B. AB⁻
    C. O⁺
    D. O⁻

12. Which enzyme is present in gastric juice?
    A. Pepsin
    B. Ptyalin
    C. Lipase
    D. Sucrase

13. Which of the following is a bacterial disease?
    A. Influenza
    B. Tuberculosis
    C. Ringworm
    D. Kala-azar

14. The gap between two neurons is called:
    A. Synapse
    B. Dendrite
    C. Axon
    D. Cyton

15. In plants, the site of photorespiration is:
    A. Chloroplast
    B. Peroxisome
    C. Glyoxysome
    D. Both (A) and (B)

16. Which hormone causes ‘fight-or-flight’ response?
    A. Insulin
    B. Adrenaline
    C. Thyroxine
    D. Oestrogen

17. The disease ‘Pellagra’ is due to deficiency of:
    A. Vitamin B₃
    B. Vitamin B₁
    C. Vitamin C
    D. Vitamin K

18. The part of the eye where the optic nerve leaves is:
    A. Cornea
    B. Iris
    C. Retina
    D. Blind spot

19. Which of the following is a monocot plant?
    A. Mustard
    B. Pea
    C. Wheat
    D. Sunflower

20. The bacteria found in root nodules of legumes is:
    A. Azotobacter
    B. Rhizobium
    C. Clostridium
    D. Nostoc

21. Which one of the following is the correct sequence of body’s defence layers?
    A. Skin → Inflammation → Interferon → Antibodies
    B. Skin → Interferon → Inflammation → Antibodies
    C. Antibodies → Skin → Inflammation → Interferon
    D. Interferon → Skin → Antibodies → Inflammation

22. Which blood vessel carries oxygenated blood from the lungs to the heart?
    A. Pulmonary artery
    B. Pulmonary vein
    C. Vena cava
    D. Aorta

23. Assertion (A): Rings of cartilage are present in the trachea.
    Reason (R): They prevent collapse of the trachea during expiration.
    A. Both A and R are true and R is the correct explanation of A.
    B. Both A and R are true but R is NOT the correct explanation of A.
    C. A is true but R is false.
    D. A is false but R is true.

24. The ‘Krebs cycle’ occurs in:
    A. Cytoplasm
    B. Outer mitochondrial membrane
    C. Mitochondrial matrix
    D. Inner mitochondrial cristae

25. Which of the following pairs is incorrectly matched?
    A. Insulin – Pancreas
    B. Thyroxine – Thyroid
    C. Cortisol – Adrenal cortex
    D. Calcitonin – Parathyroid

Answers & Explanations

1. AnswerCorrect: C. Neuron. Explanation: Neuron is nervous tissue; the rest are connective tissues.
2. AnswerCorrect: C. Chlorophyll. Explanation: Chlorophyll-a is the primary pigment that traps light for photosynthesis.
3. AnswerCorrect: B. Mitochondrion. Explanation: Site of ATP (energy) synthesis via aerobic respiration.
4. AnswerCorrect: C. Iodine. Explanation: Iodine is needed to synthesise thyroxine hormone in thyroid.
5. AnswerCorrect: B. Medulla oblongata. Explanation: It controls involuntary actions—heartbeat, breathing.
6. AnswerCorrect: B. Haemophilia. Explanation: A sex-linked (X-chromosome) recessive bleeding disorder.
7. AnswerCorrect: A. Female Anopheles mosquito. Explanation: Only female Anopheles carries Plasmodium, the malarial parasite.
8. AnswerCorrect: C. Zinc. Explanation: Required in <10 mmol kg⁻¹ dry matter; others are macronutrients.
9. AnswerCorrect: B. Tricuspid valve. Explanation: Three flaps between right atrium & ventricle; mitral is on left side.
10. AnswerCorrect: A. Digestion of fat. Explanation: Salivary lipase is negligible; fat digestion starts in the stomach.
11. AnswerCorrect: B. AB⁻. Explanation: AB⁻ has no anti-A, anti-B, anti-Rh antibodies → can receive any group.
12. AnswerCorrect: A. Pepsin. Explanation: Secreted as pepsinogen by chief cells, activated in acidic pH.
13. AnswerCorrect: B. Tuberculosis. Explanation: Caused by Mycobacterium tuberculosis; others are viral/fungal/protozoan.
14. AnswerCorrect: A. Synapse. Explanation: Synaptic cleft transmits nerve impulse via neurotransmitters.
15. AnswerCorrect: D. Both (A) and (B). Explanation: Photorespiration involves chloroplast (light reaction) + peroxisome (glycolate pathway).
16. AnswerCorrect: B. Adrenaline. Explanation: Secreted by adrenal medulla; increases heart rate, blood glucose.
17. AnswerCorrect: A. Vitamin B₃ (Niacin). Explanation: Deficiency causes 3D’s—dermatitis, diarrhoea, dementia.
18. AnswerCorrect: D. Blind spot. Explanation: Area devoid of photoreceptor cells where optic nerve exits.
19. AnswerCorrect: C. Wheat. Explanation: Has single cotyledon, parallel venation—hallmarks of monocots.
20. AnswerCorrect: B. Rhizobium. Explanation: Symbiotic nitrogen fixer; forms root nodules in legumes.
21. AnswerCorrect: A. Skin → Inflammation → Interferon → Antibodies. Explanation: Physical barrier first, then non-specific chemicals, then specific immunity.
22. AnswerCorrect: B. Pulmonary vein. Explanation: Only vein in body that carries oxygenated blood (from lung to left atrium).
23. AnswerCorrect: A. Both A and R are true and R is the correct explanation of A. Explanation: C-shaped cartilage rings keep airway patent during low intrathoracic pressure.
24. AnswerCorrect: C. Mitochondrial matrix. Explanation: Krebs (TCA) cycle enzymes are soluble in matrix; ETS on cristae.
25. AnswerCorrect: D. Calcitonin – Parathyroid. Explanation: Calcitonin is from thyroid ‘C’ cells; parathyroid secretes PTH.

Quick-Fire Shortcuts & Tips

1. Mnemonic for 5 plant macronutrients: “C. HOPKiN’S CaFe Mg” – C, H, O, P, K, N, S, Ca, Fe, Mg.
2. Valves口诀: “L3 R3” – Left (Bicuspid=2, but called Mitral), Right (Tricuspid=3).
3. Blood flow order: Body → SVC/IVC → RA → RV → Pulmonary artery → Lungs → Pulmonary vein → LA → LV → Aorta → Body.
4. Exocrine vs Endocrine: Exo = exits via duct (saliva, bile); Endo = directly blood (insulin, thyroxine).
5. Disease trio: Malaria (Protozoa, Anopheles), Kala-azar (Protozoa, Sandfly), Dengue (Virus, Aedes).
6. Vitamin口诀: B₁ = Beri-Beri; B₃ = Pellagra; C = Scurvy; D = Rickets.
7. PYQ Fact: “Largest gland” = Liver; “Largest organ” = Skin; “Second largest gland” = Pancreas.
8. Rule of 90°: In photosynthesis light & dark reactions, remember 90% ATP made in light, 90% NADPH used in Calvin.
9. Skip & flag: Biology Q’s are short; attempt within 25-30s each. Mark unsure ones, return after finishing quant.
10. One-liner cards: Write pathogen + vector + target organ on 3×5 cards; revise daily for 10 min—this alone fetches 4-5 sure marks.

Good luck—revise, recall, repeat!