The following are the stages of life cycle of Plasmodium. Arrange the stages in the proper order. A. The parasites reproduce asexually in RBCs, bursting the cells. B. The parasites reproduce asexually in liver cells, bursting the cells and releasing into blood. C. Gametocytes develop in RBCs. D. Sporozoites reach the liver through the blood. E. Female mosquito injects sporozoites into humans during bite. Choose the correct answer from the options given below:
Answer: (A) E, D, B, A, C. Answer: (A) E, D, B, A, C.
- A.E, D, B, A, C✓
- B.A, B, C, D, E
- C.C, A, B, D, E
- D.E, C, D, B, A
Correct Answer
(A) E, D, B, A, C
Solution & Explanation
Answer: (A) E, D, B, A, C. Solution: The correct life-cycle order is: E — infected female (Anopheles) mosquito injects sporozoites into humans during the bite; D — the sporozoites reach the liver through the blood; B — the parasites multiply asexually in liver cells, bursting them and releasing into blood; A — the parasites then multiply asexually in RBCs, bursting the cells (releasing toxic haemozoin → chill and fever); C — finally gametocytes develop in the RBCs (to be picked up by the next mosquito). NCERT: Plasmodium enters as sporozoites through the mosquito bite, multiplies first in liver cells, then attacks the RBCs causing their rupture. Why not the others: Sequences beginning with A, B or C are wrong because the cycle in humans must begin with the mosquito injecting sporozoites (E); liver-stage multiplication (B) must precede RBC-stage multiplication (A); and gametocyte formation (C) is the last human-stage event. NCERT Reference: NCERT Ch7, p.131, lines 34-42: "The parasites initially multiply within the liver cells and then attack the red blood cells"