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How does plasmodium multiply ? Also draw it\'s diagram. |
| Answer» \xa0\tPlasmodium completes its life cycle in two hosts, therefore, it is called digenetic endoparasite.\tMan is its primary host in which it completes its asexual cycle.\xa0\tFemale\xa0Anopheles\xa0mosquito is its vector or secondary host in which it completes its sexual cycle.\tSporozoites are present in the salivary glands of female\xa0Anopheles\xa0mosquito.\tThey enter the human blood and reach the liver cells.\tIn liver cells, the sporozoites undergo asexual multiple fission and form new cells called merozoites.\tLiver cells burst out to release the merozoites.\tThese merozoites enter the RBCs and start the erythrocytic phase.\tMerozoites pass through trophozoite stage and\xa0signet ring trophozoite stage.\tSignet ring trophozoite ingests proteins of the cytoplasm of RBCs.\tIt forms food vacuoles inside which it secretes digestive enzymes.\tThese enzymes proteolysed blood haemoglobin and break it into protein globin and haematin pigment.\tGlobin protein gets digested by the trophozoite.\tUnused haematin forms malarial pigment called haemozoin.\tTrophozoite increases in size and becomes rounded called schizont.\tSchizont undergoes multiple fission and forms many daughter nuclei.\tHaemozoin granules accumulate in the cytoplasm of RBCs.\tRBCs burst to release merozoites and the haemozoin granules.\tThe release of haemozoin granules causes malarial fever.\tMerozoites lose the ability to reproduce and thus form gametes.\tThese gametes enter the female Anopheles mosquito.\tMale and female gametes undergo fertilization to form immobile zygotes\xa0\tLater zygotes become worm-like and motile called ookinete which pierces peritrophic membrane and reach the outer layer of the stomach.\tThe ookinete becomes rounded and encloses itself in a cyst and is called oocyst.\tOocyst takes nutrients from the wall of the stomach and increases in size.\tOocyst undergoes mitotic division and forms many micro daughter nuclei.\tIn the cytoplasm, large irregular non-contractile vacuoles are formed.\tDaughter nuclei arrange around the surface of the vacuoles and get enclosed by cytoplasm.\tInside oocyst, many lobes of cytoplasm are formed with the nucleus at its centre.\tEach lobe converts into the spindle-shaped structure and hangs down in the oocyst.\tOocyst bursts and sporozoites become free in the haemocoel.\tSporozoites swim in the haemolymph and reach salivary glands of the mosquito. | |