Application-Based MCQs
1. Which organ is primarily responsible for pumping blood throughout the human body?
(A) Lungs
(B) Heart
(C) Kidney
(D) Liver
Answer: (B) Heart
Explanation: The heart acts as a muscular pump that circulates blood throughout the body.
2. The primary function of the lungs is:
(A) Digestion of food
(B) Filtration of blood
(C) Exchange of oxygen and carbon dioxide
(D) Production of insulin
Answer: (C) Exchange of oxygen and carbon dioxide
3. Which organ filters the blood and forms urine?
(A) Liver
(B) Kidney
(C) Pancreas
(D) Spleen
Answer: (B) Kidney
4. Which organ produces bile and plays a major role in detoxification?
(A) Liver
(B) Kidney
(C) Pancreas
(D) Stomach
Answer: (A) Liver
5. Which organ produces insulin?
(A) Thyroid
(B) Pancreas
(C) Liver
(D) Pituitary
Answer: (B) Pancreas
6. Thyroxine is produced by the:
(A) Adrenal gland
(B) Thyroid gland
(C) Pituitary gland
(D) Pancreas
Answer: (B) Thyroid gland
7. Which gland is commonly called the “master gland” because it regulates several other endocrine glands?
(A) Thyroid
(B) Pituitary
(C) Adrenal
(D) Pancreas
Answer: (B) Pituitary gland
8. Which blood cells are primarily responsible for transporting oxygen?
(A) WBCs
(B) RBCs
(C) Platelets
(D) Plasma cells
Answer: (B) RBCs
9. The primary function of white blood cells is:
(A) Oxygen transport
(B) Blood clotting
(C) Defence against pathogens
(D) Transport of hormones only
Answer: (C) Defence against pathogens
10. Which component of blood plays the main role in clot formation?
(A) RBCs
(B) WBCs
(C) Platelets
(D) Plasma
Answer: (C) Platelets
11. The oxygen-carrying pigment present in red blood cells is:
(A) Insulin
(B) Haemoglobin
(C) Melanin
(D) Keratin
Answer: (B) Haemoglobin
12. Insulin helps the body by:
(A) Increasing blood glucose
(B) Lowering blood glucose
(C) Increasing blood pressure
(D) Producing bile
Answer: (B) Lowering blood glucose
13. What is the major digestive function of bile?
(A) Digestion of proteins
(B) Emulsification of fats
(C) Digestion of starch
(D) Absorption of glucose
Answer: (B) Emulsification of fats
14. Gas exchange between air and blood occurs mainly in the:
(A) Bronchi
(B) Trachea
(C) Alveoli
(D) Diaphragm
Answer: (C) Alveoli
15. The functional unit of the kidney is:
(A) Neuron
(B) Nephron
(C) Alveolus
(D) Villus
Answer: (B) Nephron
16. The functional unit of the nervous system is the:
(A) Nephron
(B) Neuron
(C) Alveolus
(D) Axon
Answer: (B) Neuron
17. Which cell organelle is known as the major site of ATP production in aerobic respiration?
(A) Ribosome
(B) Mitochondrion
(C) Lysosome
(D) Golgi apparatus
Answer: (B) Mitochondrion
18. Protein synthesis occurs primarily on:
(A) Ribosomes
(B) Lysosomes
(C) Vacuoles
(D) Centrioles
Answer: (A) Ribosomes
19. Which organelle is responsible for photosynthesis in plant cells?
(A) Mitochondrion
(B) Chloroplast
(C) Ribosome
(D) Nucleus
Answer: (B) Chloroplast
20. Stomata in leaves are mainly involved in:
(A) Absorption of minerals from soil
(B) Gas exchange and regulation of water loss
(C) Production of seeds
(D) Transport of food through roots
Answer: (B) Gas exchange and regulation of water loss
21. Which plant tissue primarily transports water and minerals from roots to other parts?
(A) Phloem
(B) Xylem
(C) Epidermis
(D) Cambium
Answer: (B) Xylem
22. Food produced by photosynthesis is mainly transported through:
(A) Xylem
(B) Phloem
(C) Stomata
(D) Root hairs
Answer: (B) Phloem
Vitamins & Minerals
23. Deficiency of which vitamin can cause night blindness?
(A) Vitamin A
(B) Vitamin B₁₂
(C) Vitamin C
(D) Vitamin K
Answer: (A) Vitamin A
24. Deficiency of vitamin C causes:
(A) Rickets
(B) Scurvy
(C) Beriberi
(D) Night blindness
Answer: (B) Scurvy
25. Vitamin D is particularly important for:
(A) Calcium absorption and bone health
(B) Blood clotting only
(C) Night vision
(D) Production of insulin
Answer: (A) Calcium absorption and bone health
26. Which vitamin is important for normal blood clotting?
(A) Vitamin A
(B) Vitamin C
(C) Vitamin D
(D) Vitamin K
Answer: (D) Vitamin K
27. Iron is essential for the formation of:
(A) Haemoglobin
(B) Insulin
(C) Bile
(D) Thyroxine
Answer: (A) Haemoglobin
28. Iodine is essential for the production of:
(A) Insulin
(B) Thyroid hormones
(C) Haemoglobin
(D) Bile
Answer: (B) Thyroid hormones
Diseases & Causative Organisms
29. A patient has recurrent fever caused by infection with Plasmodium. Which disease does the patient most likely have?
(A) Typhoid
(B) Malaria
(C) Tuberculosis
(D) Dengue
Answer: (B) Malaria
30. Which of the following correctly matches the disease with its causative organism?
(A) Tuberculosis — Mycobacterium tuberculosis
(B) Malaria — HIV
(C) AIDS — Plasmodium
(D) Typhoid — Dengue virus
Answer: (A) Tuberculosis — Mycobacterium tuberculosis
Must-Memorize “Organ → Function” Associations
| Organ/Structure | Main Function |
|---|---|
| Heart | Pumps blood |
| Lungs | Gas exchange |
| Kidneys | Filter blood and form urine |
| Liver | Detoxification + bile production |
| Pancreas | Insulin production |
| Thyroid | Thyroid hormone production |
| Pituitary | Major regulatory/master endocrine gland |
| RBC | Oxygen transport |
| WBC | Immunity/defence |
| Platelets | Blood clotting |
| Haemoglobin | Oxygen transport |
| Alveoli | Gas exchange |
| Nephron | Functional unit of kidney |
| Neuron | Functional unit of nervous system |
| Mitochondria | ATP production |
| Ribosome | Protein synthesis |
| Chloroplast | Photosynthesis |
| Stomata | Gas exchange + transpiration |
| Xylem | Water/mineral transport |
| Phloem | Food transport |
Application-Based Disease Associations
Insulin deficiency → Diabetes mellitus
Iodine deficiency → Goitre
Iron deficiency → Anaemia
Vitamin A deficiency → Night blindness
Vitamin C deficiency → Scurvy
Vitamin D deficiency → Rickets/osteomalacia
Vitamin K deficiency → Impaired blood clotting
Malaria → Plasmodium
Tuberculosis → Mycobacterium tuberculosis
Typhoid → Salmonella Typhi
AIDS → HIV
Dengue → Dengue virus
Rabies → Rabies virus