Life Processes – 50 Hard MCQs
Nutrition
1. Which of the following is NOT a product of photosynthesis?
(a) Oxygen
(b) ATP
(c) Glucose
(d) Lactic acid
2. The enzyme ptyalin acts on:
(a) Proteins
(b) Fats
(c) Starch
(d) Cellulose
3. Which part of the alimentary canal receives bile juice?
(a) Stomach
(b) Duodenum
(c) Jejunum
(d) Ileum
4. Which structure prevents food from entering the windpipe?
(a) Glottis
(b) Epiglottis
(c) Trachea
(d) Larynx
5. In human digestion, maximum absorption of digested food occurs in:
(a) Stomach
(b) Duodenum
(c) Small intestine (ileum)
(d) Large intestine
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Respiration
6. In anaerobic respiration of yeast, end products are:
(a) Ethanol + CO₂ + ATP
(b) Lactic acid + ATP
(c) Pyruvate + ATP
(d) Water + ATP
7. In mitochondria, energy is released by:
(a) Glycolysis
(b) Electron transport chain
(c) Krebs cycle
(d) Both (b) and (c)
8. The number of ATP molecules produced in complete oxidation of one glucose molecule is:
(a) 2
(b) 18
(c) 36
(d) 38
9. Which part of human respiratory system has ciliated epithelium to filter air?
(a) Nasal cavity
(b) Trachea
(c) Alveoli
(d) Diaphragm
10. The ultimate hydrogen acceptor in aerobic respiration is:
(a) NAD⁺
(b) FAD
(c) Oxygen
(d) Carbon dioxide
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Transportation
11. Which blood vessel carries oxygenated blood from lungs to heart?
(a) Pulmonary artery
(b) Pulmonary vein
(c) Aorta
(d) Vena cava
12. Which chamber of human heart pumps blood to whole body?
(a) Right atrium
(b) Right ventricle
(c) Left atrium
(d) Left ventricle
13. Which type of circulation is found in humans?
(a) Open
(b) Single
(c) Double
(d) Incomplete
14. The clotting of blood requires:
(a) Fibrinogen
(b) Thromboplastin
(c) Calcium ions
(d) All of these
15. Which one transports food in plants?
(a) Xylem vessels
(b) Xylem tracheids
(c) Phloem
(d) Guard cells
16. Which pressure is responsible for movement of water in xylem?
(a) Osmotic pressure
(b) Root pressure
(c) Capillary pressure
(d) Blood pressure
17. Lymph is different from blood because it lacks:
(a) Plasma
(b) RBCs
(c) WBCs
(d) Antibodies
18. In plants, upward movement of water mainly depends on:
(a) Root pressure
(b) Transpiration pull
(c) Osmosis
(d) Imbibition
19. Which of the following carries deoxygenated blood?
(a) Aorta
(b) Pulmonary vein
(c) Pulmonary artery
(d) Coronary artery
20. Which organ produces heparin (anticoagulant)?
(a) Heart
(b) Liver
(c) Spleen
(d) Kidney
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Excretion
21. Functional unit of kidney is:
(a) Nephron
(b) Alveolus
(c) Neuron
(d) Ureter
22. Urea is formed in:
(a) Kidney
(b) Liver
(c) Heart
(d) Small intestine
23. Which part of nephron collects filtrate from Bowman’s capsule?
(a) Collecting duct
(b) Proximal convoluted tubule
(c) Henle’s loop
(d) Distal convoluted tubule
24. In which form is nitrogen excreted in humans?
(a) Ammonia
(b) Uric acid
(c) Urea
(d) Amino acids
25. Artificial kidney works on the principle of:
(a) Active transport
(b) Ultrafiltration and diffusion
(c) Endocytosis
(d) Osmosis only
26. In human excretory system, urine is carried from kidneys to bladder by:
(a) Urethra
(b) Ureter
(c) Tubules
(d) Nephron
27. Excess salts are removed from plants by:
(a) Transpiration
(b) Diffusion
(c) Shedding of leaves
(d) Lenticels
28. Which process in nephron is responsible for glucose reabsorption?
(a) Filtration
(b) Diffusion
(c) Selective reabsorption
(d) Active secretion
29. In desert plants, the main waste product is:
(a) Ammonia
(b) Urea
(c) Uric acid
(d) CO₂
30. Which organ in plants stores excretory products as crystals?
(a) Vacuole
(b) Chloroplast
(c) Nucleus
(d) Cell wall
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Mixed Concepts
31. Haemoglobin has affinity for:
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Carbon monoxide
32. Which gas forms a stable complex with haemoglobin?
(a) O₂
(b) CO₂
(c) CO
(d) H₂
33. Glucose is transported in plants as:
(a) Starch
(b) Maltose
(c) Sucrose
(d) Fructose
34. Which of the following shows both endocrine and exocrine function?
(a) Liver
(b) Kidney
(c) Pancreas
(d) Stomach
35. The wall of alveoli is:
(a) Thick and permeable
(b) Thin and permeable
(c) Thick and impermeable
(d) Thin and impermeable
36. In dialysis, the fluid used is:
(a) Plasma
(b) Dialysing solution similar to plasma
(c) Pure water
(d) Saline water
37. Blood is filtered in kidney at:
(a) Bowman’s capsule
(b) Collecting duct
(c) Ureter
(d) Glomerulus
38. If guard cells swell, stomata:
(a) Close
(b) Open
(c) Burst
(d) Remain unchanged
39. In mammals, maximum CO₂ is transported as:
(a) Carbamino-haemoglobin
(b) Dissolved in plasma
(c) Bicarbonates in plasma
(d) Free CO₂
40. Which blood group is universal donor?
(a) A
(b) B
(c) AB
(d) O
41. Which blood group is universal recipient?
(a) A
(b) B
(c) AB
(d) O
42. Which enzyme digests protein in stomach?
(a) Trypsin
(b) Pepsin
(c) Lipase
(d) Ptyalin
43. Which pigment gives green colour to plants?
(a) Carotene
(b) Xanthophyll
(c) Chlorophyll
(d) Anthocyanin
44. Plants lose excess water through:
(a) Photosynthesis
(b) Respiration
(c) Transpiration
(d) Guttation
45. Which chamber of human heart receives oxygenated blood from lungs?
(a) Right atrium
(b) Right ventricle
(c) Left atrium
(d) Left ventricle
46. The enzyme lipase acts on:
(a) Protein
(b) Fat
(c) Carbohydrate
(d) Vitamin
47. In plants, phloem transports food by:
(a) Root pressure
(b) Transpiration pull
(c) Active transport using ATP
(d) Diffusion
48. Which part of alimentary canal absorbs water and minerals?
(a) Stomach
(b) Small intestine
(c) Large intestine
(d) Duodenum
49. Which part of brain regulates thirst and excretion?
(a) Medulla
(b) Hypothalamus
(c) Cerebellum
(d) Pons
50. Which is the universal energy currency of the cell?
(a) Glucose
(b) Pyruvate
(c) ATP
(d) NADH
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✅ Answer Key
1-d, 2-c, 3-b, 4-b, 5-c
6-a, 7-d, 8-d, 9-b, 10-c
11-b, 12-d, 13-c, 14-d, 15-c
16-b, 17-b, 18-b, 19-c, 20-b
21-a, 22-b, 23-b, 24-c, 25-b
26-b, 27-c, 28-c, 29-c, 30-a
31-a, 32-c, 33-c, 34-c, 35-b
36-b, 37-d, 38-b, 39-c, 40-d
41-c, 42-b, 43-c, 44-c, 45-c
46-b, 47-c, 48-c, 49-b, 50-c
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