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Questions and Answers
What type of organisms are protozoa?
What characteristic do protozoa lack?
Which protozoan is known to cause malaria?
How many species of protozoans are there approximately?
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Which function is performed by different cell organelles in protozoa similar to higher animals?
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What is the function of the central vacuole in cellular structure?
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Which type of nucleus do ciliates possess?
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Which of these structures is responsible for locomotion in cells?
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What is a pellicle?
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Which protozoans' nucleoli contain DNA?
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Study Notes
Characteristics of Protozoa
- Protozoa are unicellular, eukaryotic, and heterotrophic organisms.
- They can be either free-living or parasites.
- There are approximately 65,000 species of protozoans, categorized into different groups.
- They lack a cell wall.
Cellular Structure
- Protozoa have a eukaryotic cell with a single membrane-bound nucleus.
- The nucleus has a diffused appearance due to scattered chromatin, and contains a central body called endosome or nucleoli.
- Nucleoli of apicomplexans have DNA, whereas those of amoeboid protozoa lack DNA.
- Ciliates have both micronucleus and macronucleus.
- The plasma membrane encloses the cytoplasm and locomotory projections like flagella, pseudopodia, and cilia.
Cell Organelles and Structures
- Some protozoa have a membranous envelope called pellicle, which gives a definite shape to the cell.
- Epibiotic bacteria can attach to the pellicle by their fimbriae in some protozoans.
- The cytoplasm is differentiated into outer ectoplasm and inner endoplasm, with ectoplasm being transparent and endoplasm containing cell organelles.
- Some protozoa have a cytostome for ingesting food, and food vacuoles where ingested food is stored.
- Ciliates have a gullet, a body cavity that opens outside.
- A central vacuole is present in some protozoa for osmoregulation, removing excess water.
- Membrane-bound cell organelles, such as mitochondria, Golgi bodies, lysosomes, and other specialized structures, are present.
Pathogenic Protozoa
- Some protozoa cause diseases in animals and humans, such as Plasmodium (malaria), Trypanosoma (sleeping sickness), and Trichomonas (trichomoniasis).
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Description
This quiz covers the cellular structure of protozoa, including their unicellular eukaryotic nature, specialized internal structures, and unique characteristics of their nucleus and membranes.
