17.Site of formation of gametes and fertilisation in the life cycle of Plasmodium is A. Human blood and liver B. Stomach of the mosquito C. Salivary glands of the mosquito D. RBCs of humans
Option B. There are 3 stages of the life cycle of Plasmodium. These are the infection of a human with sporozoites, asexual reproduction, and sexual reproduction. The first and second stages take place into the human body and the third stage starts in the human body and completes into the mosquito. When an infected mosquito bites, the sporozoites in the saliva is transferred into the blood circulation. That is the first stage of life cycle of Plasmodium. In the second stage, the sporozoites enter the liver and start dividing to form schizont. Each schizont releases many merozoites into the blood stream. Merozoites then enters the red blood cells. This is the beginning of third phase. The merozoites evolves into a trophozoite. Trophozoite is then converted into erythrocytic schizont. Each mature schizont gives birth to new generation merozoites. When RBC is ruptured, these are released in the blood stream and invade other RBCs. These merozoites then differentiate into male and female gametocytes. When a female Anopheles mosquito bites an infected person, gametocytes enters the blood of mosquito. In mosquito, these gametocytes become microgametes (male gamete) and macrogametes (female gamete). In the intestine of mosquito, male and female gamete fertilize to form a zygote. This zygote becomes ookinete and later oocyte. When the oocyst ruptures, the sporozoites enters the salivary gland of mosquito
