AFNS Biology Test Preparation is most important for AFNS Academic Test. Biology carries the highest weightage in the AFNS academic test (~25–30%). This page contains 60 solved MCQs based on the most repeated topics from actual AFNS test experiences. Every answer includes a short explanation — not just the answer key.
See also: AFNS Syllabus biology Percentage 2026 | Complete AFNS Preparation Guide
AFNS Biology MCQs Online
Section 1: Cell Biology (Most Repeated)
Q1. Which organelle is called the “powerhouse of the cell”?
A) Ribosome B) Nucleus C) Mitochondria D) Golgi Body
✅ Answer: C — Mitochondria
Explanation: Mitochondria produce ATP (energy) through cellular respiration — hence “powerhouse.” This is the single most repeated biology MCQ in AFNS tests.
Q2. Which type of cell division produces gametes (egg and sperm)?
A) Mitosis B) Meiosis C) Binary Fission D) Budding
✅ Answer: B — Meiosis
Explanation: Meiosis reduces chromosome number by half (haploid cells) to produce sex cells. Mitosis produces identical body cells for growth and repair.
Q3. The cell membrane is primarily made of:
A) Carbohydrates B) Proteins C) Phospholipid bilayer D) DNA
✅ Answer: C — Phospholipid bilayer
Explanation: The cell membrane consists of a double layer of phospholipids with embedded proteins. This is the fluid mosaic model.
Q4. Which organelle is responsible for protein synthesis?
A) Lysosome B) Ribosome C) Vacuole D) Centrosome
✅ Answer: B — Ribosome
Explanation: Ribosomes translate mRNA into proteins. They are found free in the cytoplasm or attached to rough ER.
Q5. Osmosis is the movement of:
A) Solutes from high to low concentration B) Water from low to high solute concentration C) Water from high to low solute concentration D) Ions against a gradient
✅ Answer: B — Water from low to high solute concentration
Explanation: Osmosis moves water through a semipermeable membrane from dilute (low solute) to concentrated (high solute) solution.
Section 2: Human Physiology
Q6. The normal human heart rate (resting) is:
A) 40–60 bpm B) 60–100 bpm C) 100–120 bpm D) 120–140 bpm
✅ Answer: B — 60–100 bpm
Explanation: Normal resting heart rate for adults is 60–100 beats per minute. Athletes may be lower (40–60). Above 100 is tachycardia.
Q7. Where does digestion of proteins begin?
A) Mouth B) Oesophagus C) Stomach D) Small Intestine
✅ Answer: C — Stomach
Explanation: Pepsin (enzyme) in the stomach begins protein digestion. Carbohydrate digestion begins in the mouth (salivary amylase). Fat digestion mainly in small intestine.
Q8. Which blood type is called the “universal donor”?
A) A B) B C) AB D) O
✅ Answer: D — O (specifically O negative)
Explanation: O negative has no A, B, or Rh antigens, so it can be given to any patient without triggering immune rejection. AB is the universal recipient.
Q9. The functional unit of the kidney is called:
A) Alveolus B) Nephron C) Glomerulus D) Neuron
✅ Answer: B — Nephron
Explanation: Each kidney contains ~1 million nephrons. The nephron filters blood to produce urine. The glomerulus is the filtering structure inside the nephron.
Q10. Gas exchange in the lungs occurs in:
A) Bronchi B) Trachea C) Alveoli D) Bronchioles
✅ Answer: C — Alveoli
Explanation: Alveoli are tiny air sacs with thin walls and rich blood supply, allowing O₂ and CO₂ to diffuse across the membrane.
Q11. Which part of the brain controls breathing and heartbeat?
A) Cerebrum B) Cerebellum C) Medulla Oblongata D) Hypothalamus
✅ Answer: C — Medulla Oblongata
Explanation: The medulla oblongata controls involuntary functions: breathing, heart rate, blood pressure, swallowing. Cerebellum controls balance and coordination.
Q12. The largest gland in the human body is:
A) Pancreas B) Thyroid C) Liver D) Adrenal
✅ Answer: C — Liver
Explanation: The liver is the largest internal organ and gland. It performs over 500 functions including bile production, detoxification, and glycogen storage.
Q13. Insulin is produced by:
A) Liver B) Thyroid C) Beta cells of Pancreas D) Adrenal gland
✅ Answer: C — Beta cells of Pancreas
Explanation: Beta cells in the Islets of Langerhans produce insulin. Alpha cells produce glucagon. Diabetes results from insulin deficiency or resistance.
Q14. Normal blood pressure in adults is:
A) 100/60 mmHg B) 120/80 mmHg C) 140/100 mmHg D) 80/60 mmHg
✅ Answer: B — 120/80 mmHg
Explanation: 120/80 is standard normal. Systolic (top number) is pressure during heartbeat; diastolic (bottom) is between beats. Above 140/90 is hypertension.
Q15. Which vitamin is produced by the skin on exposure to sunlight?
A) Vitamin A B) Vitamin B12 C) Vitamin C D) Vitamin D
✅ Answer: D — Vitamin D
Explanation: UV light converts 7-dehydrocholesterol in the skin to Vitamin D3. Deficiency causes rickets in children and osteomalacia in adults.
Section 3: Nutrition & Vitamins
Q16. Deficiency of Vitamin C causes:
A) Rickets B) Scurvy C) Night blindness D) Anaemia
✅ Answer: B — Scurvy
Explanation: Vitamin C (ascorbic acid) is essential for collagen synthesis. Deficiency causes bleeding gums, weak capillaries, joint pain.
Q17. Night blindness is caused by deficiency of:
A) Vitamin B B) Vitamin C C) Vitamin A D) Vitamin K
✅ Answer: C — Vitamin A
Explanation: Vitamin A (retinol) is needed for rhodopsin production in rod cells. Deficiency impairs vision in dim light (night blindness).
Q18. Which nutrient provides the most energy per gram?
A) Carbohydrates B) Proteins C) Fats D) Vitamins
✅ Answer: C — Fats
Explanation: Fats yield 9 kcal/g, while carbohydrates and proteins yield 4 kcal/g each. Vitamins provide no energy.
Q19. Iron deficiency causes:
A) Goitre B) Anaemia C) Scurvy D) Rickets
✅ Answer: B — Anaemia
Explanation: Iron is required for haemoglobin synthesis. Iron-deficiency anaemia is most common in females — extremely relevant to nursing context.
Q20. Iodine deficiency causes:
A) Anaemia B) Goitre C) Diabetes D) Night blindness
✅ Answer: B — Goitre
Explanation: The thyroid gland needs iodine to produce thyroid hormones. Deficiency causes the gland to enlarge (goitre). Iodised salt is the preventive measure.
Section 4: Genetics
Q21. The basic unit of heredity is:
A) Chromosome B) Cell C) Gene D) Nucleus
✅ Answer: C — Gene
Explanation: Genes are segments of DNA that code for specific proteins or traits. Multiple genes are carried on each chromosome.
Q22. Human body cells contain how many chromosomes?
A) 23 B) 46 C) 44 D) 48
✅ Answer: B — 46 (23 pairs)
Explanation: Humans have 46 chromosomes (23 pairs) in diploid body cells. Gametes (egg/sperm) have 23 chromosomes (haploid).
Q23. Down syndrome is caused by:
A) Deletion of chromosome 21 B) Trisomy 21 C) Missing X chromosome D) Mutation in chromosome 7
✅ Answer: B — Trisomy 21
Explanation: Down syndrome results from an extra copy of chromosome 21 (three instead of two). It causes intellectual disability and characteristic physical features.
Q24. Blood group is an example of which type of inheritance?
A) Monohybrid B) Codominance C) Incomplete Dominance D) Sex-linked
✅ Answer: B — Codominance
Explanation: In blood group AB, both A and B alleles are fully expressed simultaneously — this is codominance. Neither is dominant over the other.
Q25. DNA stands for:
A) Deoxyribonucleic Acid B) Dioxyribose Nucleic Acid C) Dinitrogen Acid D) Deoxyribose Nitrogen Acid
✅ Answer: A — Deoxyribonucleic Acid
Explanation: DNA is a double-helix polymer of nucleotides. Each nucleotide contains deoxyribose sugar, phosphate group, and a nitrogenous base (A, T, G, or C).
Section 5: Ecology & Microorganisms
Q26. Antibiotics are effective against:
A) Viruses B) Bacteria C) Fungi D) Prions
✅ Answer: B — Bacteria
Explanation: Antibiotics target bacterial cell walls or protein synthesis. They have no effect on viruses (which is why antibiotics should not be taken for colds or flu).
Q27. Which disease is caused by a virus?
A) Typhoid B) Cholera C) Influenza D) Tuberculosis
✅ Answer: C — Influenza
Explanation: Influenza (flu) is caused by influenza virus. Typhoid and Cholera are bacterial; TB (Mycobacterium tuberculosis) is also bacterial.
Q28. The primary producer in a food chain is:
A) Herbivore B) Carnivore C) Green plant D) Decomposer
✅ Answer: C — Green plant
Explanation: Green plants (autotrophs) produce organic matter through photosynthesis. All other organisms in the food chain depend on them directly or indirectly.
Q29. Malaria is caused by:
A) Bacteria B) Virus C) Protozoa (Plasmodium) D) Fungus
✅ Answer: C — Protozoa (Plasmodium)
Explanation: Malaria is caused by Plasmodium parasite, transmitted by the female Anopheles mosquito. It destroys red blood cells, causing fever, chills, and anaemia.
Q30. Photosynthesis takes place in:
A) Mitochondria B) Ribosome C) Chloroplast D) Nucleus
✅ Answer: C — Chloroplast
Explanation: Chloroplasts contain chlorophyll which absorbs sunlight to convert CO₂ + H₂O into glucose and O₂.
Continue your preparation: AFNS Chemistry MCQs → | AFNS Physics MCQs → | AFNS Past Papers PDF →
FAQs
What biology topics come in AFNS test?
The most repeated topics are human physiology (digestive, circulatory, respiratory, nervous, excretory systems), cell biology (organelles, division, transport), nutrition and vitamins, genetics (DNA, chromosomes, blood groups), and disease-causing microorganisms.
Is AFNS biology from FSc syllabus?
Yes — the AFNS biology portion is based entirely on FSc Part I and Part II Pre-Medical biology. Human physiology chapters from Part II are the most heavily tested.
