Notes on Sexual Cycle of Plasmodium | Grade 11 > Biology > Plasmodium | KULLABS.COM

Sexual Cycle of Plasmodium

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When a mosquito bites a malaria-infected person, it sucks gametocytes along with blood. Gametocytes then reach to the stomach of mosquito where they become mature and undergo following developmental phases.

Gametogony:

It is the process of formation of gametes from gametocytes. Micro gametocytes produce male gametes by the process of ex-flagellation. At the first nucleus of micro gametocytes divides into 6 to 8 nuclei. At the same time, an equal number of flagella like cytoplasmic extensions are also developed. Each of them carries single nucleus. Later they are separated from the main cytoplasmic body to welcome male gametes. They are active and motile. On the other hand, macro gametocyte is directly developed into female gamete after certain cytoplasmic reorganization. They are inactive and non-motile but contains reception cone.

Fertilization:

It is the fusion of male and female gametes to produce a diploid zygote. Fertilization is anisogamous i.e. male and female gametes are dissimilar. Male gamete moves towards female gamete and enters inside through reception cone. Their cytoplasm and nucleus are fused to form a zygote.

Ookinete:

At first, zygote remains rounded but later it becomes vermiform and motile. This worm-like motile zygote is called ookinete.

Oocyst:

Ookinete starts to penetrate the inner wall of the stomach and gets encysted just below the outer basement membrane. This encysted zygote or ookinete is called oocyst. Up to 500 oocysts may be present in the stomach of infected mosquito which looks like blisters.


source:www.biologydiscussion.com life cycle of plasmodium
source:www.biologydiscussion.com
fig:life cycle of plasmodium

Sporogony in Plasmodium
source:www.biologydiscussion.com
fig:Sporogony in Plasmodium

Sporogony:

It is the process of formation of a large number of haploid sporozoites from the oocysts. Up to 10,000 sporozoites are produced from a single oocyst. At first, the nucleus of oocyst divides by meiosis and then by repeated mitosis. In this way, a large number of haploid nuclei are produced in growing oocysts. Each nucleus derives cytoplasm and develops into sporozoites. Inside mature oocyst, sporozoites are arranged around the vacuolated regions of cytoplasm. When mature oocyst burst sporozoites are released into haemo coelom from where they migrate towards salivary glands and become matured. In this way, the whole sexual cycle of plasmodium in the mosquito is completed within 10 days to 3 weeks.

Control measures of mosquito:

  • Control measures of mosquito are as follow:
  • Destruction of breeding places of the mosquito by spraying kerosene oil etc.
  • Destruction of larvae and pupae in their developmental stages.
  • Farming of ducks and clearing of floating plants are also found effective to control mosquitoes.
  • Adult mosquito should be destroyed by spraying, burning, using insecticides.
  • Mosquito repellents like anti-mosquito cream, anti-mosquito mats, and mustard oil can be used to keep mosquito away.
  • Anti-malarial drugs should be used.



  • Gametogony is the process of formation of gametes from gametocytes.
  • Fertilization is anisogamous i.e. male and female gametes are dissimilar in plasmodium.
  • Sporogony is the process of formation of large number of haploid sporozoites from the oocysts. 
  • When mature oocyst burst sporozoites are released into haemocoelom from where they migrate towards salivary glands and become matured.
  • The worm-like motile zygote is called ookinete.
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