Protozoa are unicellular, eukaryotic, heterotrophic organisms. They are either free-living or parasites. There are around 65000 species of protozoans categorised in different groups. They lack a cell wall. There are many different cell organelles, that perform various tasks performed by different organs in higher animals, e.g. mouth, anus, intestinal tract, etc. There are many protozoa, that cause various diseases in animals and humans, e.g. Plasmodium (malarial parasite), Trypanosoma (sleeping sickness), Trichomonas (trichomoniasis), etc.
Protozoa Classification and Examples
Protozoa is a phylum having unicellular heterotrophs. It comes under Kingdom Protista.
Protozoa are divided into four major groups based on the structure and the part involved in the locomotion:
1. Sporozoa or Sporozoans:
They are endoparasitic.
They don’t have any specialised organ for locomotion
The pellicle is present, which has subpellicular microtubules, that help in movement
Reproduction is by sporozoite formation
Examples: Plasmodium, Myxidium, Nosema, Globidium, etc.
2. Mastigophora or Flagellated protozoans:
They are parasites or free-living.
They have flagella for locomotion
Their body is covered by a cuticle or pellicle
Freshwater forms have a contractile vacuole
Reproduction is by binary fission (longitudinal division)
Examples: Trypanosoma, Trichomonas, Giardia, Leishmania, etc.
3. Ciliophora or Ciliated protozoans:
They are aquatic and move actively with the help of thousands of cilia.
They have fixed shape due to covering of pellicle
They may have tentacles, e.g. in the sub-class Suctoria
Contractile vacuoles are present
Some species have an organ for defence called trichocysts
They move with the help of cilia and the movement of cilia also helps in taking food inside the gullet
They reproduce by transverse division and also form cysts
Examples: Paramecium, Vorticella, Balantidium, etc.
4. Sarcodina or Amoeboids:
They live in the freshwater, sea or moist soil.
The movement is by pseudopodia. They capture their prey by pseudopodia
There is no definite shape and pellicle is absent
The contractile vacuole is present in the amoeboids living in freshwater
Reproduction is by binary fission and cyst formation
Examples: Amoeba, Entamoeba, etc.
General Characteristics of Protozoa
Habitat- Protozoa are found in the aquatic environment. They live in freshwater or oceans. Some are free-living and some are parasitic in plants and animals. Mostly they are aerobic but some are anaerobic and present in the rumen or human intestine.
Some of the species are found in extreme environments like hot springs. Some of them form resting cyst to overcome dry environments.
Protozoan infections are caused by single-celled parasites called protozoa. When these parasites are introduced to the body they multiply, interfere with the body's normal functioning, and cause damage to vital organs. Protozoa usually enter the body either through an insect bite or through infected food or water.This review focuses on drug repurposing for the human parasitic protozoan diseases malaria, trypanosomiasis, leishmaniasis, toxoplasmosis, and cryptosporidiosis.
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What is Protozoa?
Protozoa are unicellular, eukaryotic, heterotrophic organisms. They are either free-living or parasites. There are around 65000 species of protozoans categorised in different groups. They lack a cell wall. There are many different cell organelles, that perform various tasks performed by different organs in higher animals, e.g. mouth, anus, intestinal tract, etc. There are many protozoa, that cause various diseases in animals and humans, e.g. Plasmodium (malarial parasite), Trypanosoma (sleeping sickness), Trichomonas (trichomoniasis), etc.
Protozoa Classification and Examples
Protozoa is a phylum having unicellular heterotrophs. It comes under Kingdom Protista.
Protozoa are divided into four major groups based on the structure and the part involved in the locomotion:
1. Sporozoa or Sporozoans:
They are endoparasitic.
2. Mastigophora or Flagellated protozoans:
They are parasites or free-living.
3. Ciliophora or Ciliated protozoans:
They are aquatic and move actively with the help of thousands of cilia.
4. Sarcodina or Amoeboids:
They live in the freshwater, sea or moist soil.
General Characteristics of Protozoa
Habitat- Protozoa are found in the aquatic environment. They live in freshwater or oceans. Some are free-living and some are parasitic in plants and animals. Mostly they are aerobic but some are anaerobic and present in the rumen or human intestine.
Some of the species are found in extreme environments like hot springs. Some of them form resting cyst to overcome dry environments.
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Answer:
Protozoan infections are caused by single-celled parasites called protozoa. When these parasites are introduced to the body they multiply, interfere with the body's normal functioning, and cause damage to vital organs. Protozoa usually enter the body either through an insect bite or through infected food or water.This review focuses on drug repurposing for the human parasitic protozoan diseases malaria, trypanosomiasis, leishmaniasis, toxoplasmosis, and cryptosporidiosis.
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