Part 1: Blood – Plasma, RBCs, WBCs, Platelets, Functions (25 MCQs)
Part 1: Blood – Plasma, RBCs, WBCs, Platelets, Functions (25 MCQs)
Q1. Which component of blood makes up about 55% of its volume?
A. Plasma
B. RBCs
C. WBCs
D. Platelets
Answer: A
Explanation:
- A. Correct: Plasma forms ~55% of blood, mainly water, proteins, nutrients.
- B. Incorrect: RBCs form ~45% (hematocrit).
- C. Incorrect: WBCs are <1%.
- D. Incorrect: Platelets are tiny fraction.
Q2. Which protein is most abundant in plasma?
A. Fibrinogen
B. Globulin
C. Albumin
D. Hemoglobin
Answer: C
Explanation:
- A. Incorrect: Fibrinogen is clotting protein, less abundant.
- B. Incorrect: Globulins provide immunity but not most abundant.
- C. Correct: Albumin maintains osmotic pressure; most abundant plasma protein.
- D. Incorrect: Hemoglobin is in RBCs, not plasma.
Q3. The main function of RBCs is:
A. Immunity
B. Oxygen transport
C. Blood clotting
D. Producing antibodies
Answer: B
Explanation:
- A. Incorrect: WBCs provide immunity.
- B. Correct: RBCs carry oxygen using hemoglobin.
- C. Incorrect: Platelets clot blood.
- D. Incorrect: Antibodies from lymphocytes.
Q4. Which cell is most abundant in human blood?
A. Neutrophil
B. Erythrocyte
C. Lymphocyte
D. Platelet
Answer: B
Explanation:
- A. Incorrect: Neutrophils most abundant WBC, but not overall.
- B. Correct: RBCs (erythrocytes) form majority of blood cells.
- C. Incorrect: Lymphocytes fewer.
- D. Incorrect: Platelets fewer.
Q5. Average lifespan of human RBCs is:
A. 60 days
B. 90 days
C. 120 days
D. 180 days
Answer: C
Explanation:
- A. Incorrect: Too short.
- B. Incorrect: Still short.
- C. Correct: RBCs live ~120 days in circulation.
- D. Incorrect: Too long.
Q6. Which organ removes old RBCs from circulation?
A. Kidney
B. Spleen
C. Liver
D. Pancreas
Answer: B
Explanation:
- A. Incorrect: Kidneys filter waste, not RBCs.
- B. Correct: Spleen is “graveyard of RBCs.”
- C. Incorrect: Liver helps recycle Hb components but not primary removal.
- D. Incorrect: Pancreas unrelated.
Q7. Hemoglobin is present in:
A. Plasma
B. RBCs
C. WBCs
D. Platelets
Answer: B
Explanation:
- A. Incorrect: Plasma has proteins but no Hb.
- B. Correct: Hb in RBCs binds O₂ and CO₂.
- C. Incorrect: WBCs don’t carry Hb.
- D. Incorrect: Platelets lack Hb.
Q8. Which WBC is the first line of defense during infection?
A. Lymphocyte
B. Basophil
C. Neutrophil
D. Eosinophil
Answer: C
Explanation:
- A. Incorrect: Lymphocytes act later (adaptive immunity).
- B. Incorrect: Basophils release histamine, not first defense.
- C. Correct: Neutrophils are phagocytes, first responders.
- D. Incorrect: Eosinophils fight parasites/allergies.
Q9. Which WBC is involved in allergic reactions and parasitic infections?
A. Neutrophil
B. Eosinophil
C. Monocyte
D. Lymphocyte
Answer: B
Explanation:
- A. Incorrect: Neutrophils handle bacteria.
- B. Correct: Eosinophils increase in allergies, parasitic infections.
- C. Incorrect: Monocytes → macrophages.
- D. Incorrect: Lymphocytes make antibodies.
Q10. Which blood cells are called “soldiers of the body”?
A. RBCs
B. Platelets
C. WBCs
D. Plasma cells
Answer: C
Explanation:
- A. Incorrect: RBCs transport gases.
- B. Incorrect: Platelets clot blood.
- C. Correct: WBCs defend body → called soldiers.
- D. Incorrect: Plasma cells make antibodies, but not all WBCs.
Q11. Which granulocyte releases histamine during allergic reactions?
A. Neutrophil
B. Eosinophil
C. Basophil
D. Monocyte
Answer: C
Explanation:
- A. Incorrect: Neutrophils phagocytose.
- B. Incorrect: Eosinophils act in allergy but not histamine release.
- C. Correct: Basophils release histamine, serotonin.
- D. Incorrect: Monocytes become macrophages.
Q12. Platelets are formed from:
A. Lymphocytes
B. Megakaryocytes
C. Neutrophils
D. Monocytes
Answer: B
Explanation:
- A. Incorrect: Lymphocytes = WBCs.
- B. Correct: Platelets are fragments of megakaryocytes in bone marrow.
- C. Incorrect: Neutrophils = granulocytes.
- D. Incorrect: Monocytes differentiate into macrophages.
Q13. Normal platelet count per mm³ of blood is:
A. 5,000–10,000
B. 50,000–100,000
C. 1,00,000–1,50,000
D. 1,50,000–3,50,000
Answer: D
Explanation:
- A. Incorrect: Too low (severe deficiency).
- B. Incorrect: Still low.
- C. Incorrect: Lower than normal.
- D. Correct: Normal platelet count = 1.5–3.5 lakh/mm³.
Q14. Which WBC differentiates into macrophages?
A. Neutrophils
B. Monocytes
C. Basophils
D. Lymphocytes
Answer: B
Explanation:
- A. Incorrect: Neutrophils don’t differentiate.
- B. Correct: Monocytes become macrophages in tissues.
- C. Incorrect: Basophils remain basophils.
- D. Incorrect: Lymphocytes → T, B, plasma cells.
Q15. Which plasma protein is essential for blood clotting?
A. Albumin
B. Globulin
C. Fibrinogen
D. Hemoglobin
Answer: C
Explanation:
- A. Incorrect: Albumin maintains osmotic pressure.
- B. Incorrect: Globulins = immunity.
- C. Correct: Fibrinogen → fibrin in clotting.
- D. Incorrect: Hb is in RBCs, not plasma.
Q16. Which plasma protein provides immunity?
A. Albumin
B. Globulin
C. Fibrinogen
D. Myoglobin
Answer: B
Explanation:
- A. Incorrect: Albumin = osmotic balance.
- B. Correct: Globulins act as antibodies.
- C. Incorrect: Fibrinogen = clotting.
- D. Incorrect: Myoglobin is muscle protein.
Q17. Erythropoietin, a hormone stimulating RBC production, is secreted by:
A. Liver
B. Kidney
C. Spleen
D. Bone marrow
Answer: B
Explanation:
- A. Incorrect: Liver does not secrete erythropoietin.
- B. Correct: Kidneys secrete erythropoietin when O₂ is low.
- C. Incorrect: Spleen destroys RBCs.
- D. Incorrect: Bone marrow produces RBCs but doesn’t secrete hormone.
Q18. The nucleus is absent in mature human:
A. WBCs
B. RBCs
C. Platelets
D. Both B and C
Answer: D
Explanation:
- A. Incorrect: WBCs have nucleus.
- B. Correct but partial: RBCs lose nucleus at maturity.
- C. Correct but partial: Platelets are cell fragments.
- D. Correct answer: Both RBCs and platelets lack nuclei.
Q19. Which blood cell type is agranulocyte?
A. Neutrophil
B. Basophil
C. Monocyte
D. Eosinophil
Answer: C
Explanation:
- A. Incorrect: Neutrophil = granulocyte.
- B. Incorrect: Basophil = granulocyte.
- C. Correct: Monocytes (and lymphocytes) are agranulocytes.
- D. Incorrect: Eosinophil = granulocyte.
Q20. Which vitamin is essential for maturation of RBCs?
A. Vitamin A
B. Vitamin B₁₂
C. Vitamin D
D. Vitamin E
Answer: B
Explanation:
- A. Incorrect: Vitamin A = vision.
- B. Correct: Vitamin B₁₂ (and folic acid) required for RBC maturation.
- C. Incorrect: Vitamin D = calcium metabolism.
- D. Incorrect: Vitamin E = antioxidant.
Q21. Which disorder is caused by deficiency of RBCs or hemoglobin?
A. Leukemia
B. Anemia
C. Polycythemia
D. Hemophilia
Answer: B
Explanation:
- A. Incorrect: Leukemia = WBC cancer.
- B. Correct: Anemia = reduced Hb or RBC count.
- C. Incorrect: Polycythemia = excess RBCs.
- D. Incorrect: Hemophilia = clotting disorder.
Q22. Which type of WBCs are involved in antibody production?
A. Neutrophils
B. Monocytes
C. B-lymphocytes
D. Basophils
Answer: C
Explanation:
- A. Incorrect: Neutrophils = phagocytosis.
- B. Incorrect: Monocytes → macrophages.
- C. Correct: B-lymphocytes differentiate into plasma cells that produce antibodies.
- D. Incorrect: Basophils release histamine.
Q23. The hematocrit value refers to the percentage of:
A. WBCs in blood
B. Plasma in blood
C. RBCs in blood
D. Platelets in blood
Answer: C
Explanation:
- A. Incorrect: WBCs form <1%.
- B. Incorrect: Plasma ≈ 55%.
- C. Correct: Hematocrit = % of RBCs in blood (~45%).
- D. Incorrect: Platelets much less.
Q24. Which condition is characterized by abnormally high WBC count?
A. Leukopenia
B. Leukemia
C. Polycythemia
D. Anemia
Answer: B
Explanation:
- A. Incorrect: Leukopenia = low WBC count.
- B. Correct: Leukemia = cancer → uncontrolled WBC production.
- C. Incorrect: Polycythemia = high RBCs.
- D. Incorrect: Anemia = low Hb.
Q25. The primary function of platelets is:
A. Oxygen transport
B. Immunity
C. Blood clotting
D. Osmotic balance
Answer: C
Explanation:
- A. Incorrect: O₂ by RBCs.
- B. Incorrect: Immunity by WBCs.
- C. Correct: Platelets release clotting factors.
- D. Incorrect: Osmotic balance by albumin.
Body Fluids and Circulation MCQs, CBSE Class 11 Biology, NEET UG Biology Preparation, Human Circulatory System Notes, Class 11 Biology Questions, NCERT Biology MCQs PDF, Circulation and Blood Quiz, NEET UG Biology MCQs, body fluids and circulation mcqs for neet, class 11 biology chapter 18 questions, cbse class 11 biology mcqs with answers, human circulatory system mcqs ncert, body fluids and circulation quiz for neet ug, class 11 biology mcqs for cbse board, ncert biology chapter 18 notes, important mcqs on body fluids class 11