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| All protozoa are unicellular eukaryotic organisms which store their genetic information in chromosomes in a nuclear envelope. Protozoa are classified depending on their structure and life cycle. This reflects the similarities of the diseases which they cause. | | All protozoa are unicellular eukaryotic organisms which store their genetic information in chromosomes in a nuclear envelope. Protozoa are classified depending on their structure and life cycle. This reflects the similarities of the diseases which they cause. |
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− | Protozoa usually range from 10μ-50μ but can grow up to 1mm. Thus, they are usually observed and classified using a microscope. | + | Protozoa usually range from 10μm-50μm but can grow up to 1mm. Thus, they are usually observed and classified using a microscope. |
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− | Protozoa multiply sexually, asexually and can also use a combination of both, for example, the coccidia class. Replication can be by binary or multiple fission. Different protozoa use different forms of motility, either flagella, cilia, pseudopodia or gliding. | + | Protozoa multiply sexually, asexually and can also use a combination of both, for example, the coccidia class. Replication can be by binary or multiple fission. Different protozoa use different forms of motility, including flagella, cilia, pseudopodia and gliding. |
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| + | ==Structure and function== |
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| + | *Motile |
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| + | *Organelles and otehr cellular structures enable the protozoa to lead an '''independent exsistence''' |
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| + | *Cilia |
| + | **Fine, short hairs covering the protozoal surface |
| + | **Hairs beat in unison to enable the protozoa to move |
| + | **Wafts food towards the cytostome (mouth opening) |
| + | **E.g. ''Balantidium'' |
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| + | *Flagellum |
| + | **Contractile fibre |
| + | **Contracts in a whip like motion to propel protozoa |
| + | **Attached to body of protozoa by an '''undulating membrane''' |
| + | **E.g. ''Trypanosoma'' |
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| + | *Pseudopodia |
| + | **Extensions of the cellular cytoplasm |
| + | **Cytoplasm flows into the pseudopodia allowing movement of the protozoa |
| + | **Also acts in a phagocytic manner surrounding food particles and enclosing it in a vacuole |
| + | **E.g. ''Entamoeba'' |
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| + | *Gliding |
| + | **No obvious means of locomotion |
| + | **E.g. ''Eimeria'' |
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| + | ==Nutrition and digestion== |
| + | [[Image:Pinocytosis.jpg|thumb|right|150px|Pinocytosis - Mariana Ruiz Villarreal]] |
| + | *Pinocytosis |
| + | **Droplets of fluid taken into the cell |
| + | **Generates small vesicles |
| + | **Usually used for extracellular fluid ingestion |
| + | **Requires ATP |
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| + | *Phagocytosis |
| + | **Larger particles of matter taken into the cell |
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| + | *Cell membrane envelops the fluid or food taking it into the cell |
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| + | *Lysosomes fuse with the fluid/food initiating digestion |
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| + | *Diffusion through the cell membrane allows excretion of metabolic products |
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| + | ==Life Cycle== |
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| ==Protozoa of Veterinary Importance== | | ==Protozoa of Veterinary Importance== |