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Unformatted text preview: Both Organisms Chapter 19 BIO 1002 1/22/2008 Chapter 19 : H idden World of Microbes I.- Microbe - (microscopic organism, especially one that transmits a disease)- too small to be seen clearly without a microscope- 3 Types: Prokaryotes , range in size from 0.2-1.0 m c) Uni-cellular Euka ryotes , range in size from 10-100 m, (or a micrometer= 1/1000 of meter; the period at the end of a sentence is about 1,000 m) - Comparison of prokaryotes, eukaryotes, and viruses- (Eukaryotic cells are the largest, then prokaryotes, and viruses are the smallest) d) Other Biological Entities: (even smaller than bacteria)- Not organisms because they dont have all of the characteristics of an independent living organism 1. Viruses- Small (0.05-0.2 m), vary in shapes and size, ex: rabies, herpes, measles- Parts: a) Genome (genetic information, can either be single- stranded or double stranded DNA or RNA) b) Capsid (protein coat which surrounds and protects genome) c) Envelope (membrane, or phospholipids bilayer, which surrounds the capsid)- Hijack cells (highly specific for organisms it infects) 2. Virods- Even simpler and smaller than viruses- Fragments of single-stranded RNA with NO protein coat (capsid)- Hijack cells; infects primarily plant cells (including citrus trees, potatoes, avocados) 3. Prions- Unusual infectious particle- Protein particle with no genetic material (ex: DNA or RNA) unlike a virus- Ex: Mad Cow, Creutzfeldt-Ja kob Disease, and Ku ru- (without enzymes you cannot survive) prions consist of a protein that is folded wrong and makes other proteins fold wrong- Origins: developed as a by-product of living organisms- Bio Remediation c) Used to clean up the environment d) Ex :) Deinococcus Radiodurans- Survive 3000x more radiation than a human being- Tolerate extreme dehydration, heat, and cold...
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- Spring '08