HLTB21H3 Lecture : Health Studies Lecture - 2.docx
17 Mar 2012
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Document Summary
Parasites organism that grows, feeds, and is sheltered on or in a different organism and that does not contribute to the survival of its host. Virus ultimate micro-parasite smaller than bacteria; neither cells not organisms; can only reproduce within their host. It"s a collection of genetic material that is engulfed in a protein. They can only be seen in an electron microscope. Parasites that are cells: bacterium"s, and protozoa"s (unicellular) one celled parasites. Macro-parasites composed of many cells; cycles through transmission stages (eggs and larvae) which pass into the external environment. Usually don"t multiply within the host , but they mostly use the host for multiplication but also to cycle through transmission stages. Use the host to lay eggs for instance. Transmission stages of eggs and larvae, which transmits its way into the external environment and find its way to impact the host once again. Are larger , and can be seen using the naked eye.
