Thursday, 21 January 2016

PROTOZOA

Protozoans are unicellular in size and some are visible to naked eye,eukaryotic,chemoheterotrophic organisms.

  • The term protozoa given by GOLD FUSS.
  • The structure of protozoa are referred to as organelles(differentiated portions of cell) which perform various activities required for metabolism as in metazoa
  • Difference between protozoa and rickettisia is  :    protozoa are eukaryotic, possess a cell wall and  organelle for performing different metabolic activities whereas rickettisia are prokaryotic like bacteria  and devoid of  well developed cell wall.
  • Protozoa form a subkingdom of the kingdom protista.

Most protozoa have two stages-
  •  Trophozoite – the feeding and growing stage
  • Some protozoa will produce a protective capsule called a cyst.
  •  A cyst allows the parasite to exist outside of the host and be the infective stage allowing the parasite to get to another host.
Protozoa reproduce sexually and asexually
 Asexually : Fission (mitosis), Budding, Schizogony.
 Sexually : Conjugation, Gamete formation.
 Definitive Host harbors the sexually reproducing stage
of parasite.
 Intermediate Host harbors asexually reproducing
portion of the parasite’s life cycle.
 Movement:
• A single or multiple flagella
• Cilia, Balantidium
• Pseudopodia, Enramoeba
• No obvious means of locomotion, Eimeria.

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