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Test 2 Notes - Note Taker

Test 2 Notes - Note Taker - Week 5 notes Other biological...

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Week 5 notes 9/19/11 Other biological entities o Not organisms Viruses Viroid’s Sampler and smaller Fragment of RNA with no protein coat o Hijack cells; infects primarily plant cells including citrus trees, potatoes, avocadoes Smaller than viruses Doesn’t make proteins but they effect the plants to where the plants can not make proteins Prions o Unusually infectious particles o Found in the brain and spinal fluid of the animal o No genome at all No RNA or DNA or single double stranded anything o A protein particle o Mad cow disease in cows and in humans it’s called Creutzfeldt-Jakob disease and kuru A human can get this disease by once killing the animal if a person messes with its head or spine if the animal has mad cow then if those prions get on the meat then humans may get mad cow o Consist of a protein that is folded wrong and makes other proteins fold wrong It does this in a very non-specific way. When prions interfere with proteins then the proteins start to stick together and make a big blob Origin? o Proteins come from living things, originated as by products of living organisms All life on the planet is either prokaryotic or eukaryotic cell types Prokaryotes: o BACTERIA and ARCHAEA Domains o 8000 species described, may be 100-1000x that number o 1 st organisms to appear on Earth, 3.5 billion years ago o Cell wall
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Semi-rigid, permeable, made of peptidoglycan (carbohydrate with amino acids attached) gives bacteria shapes Shapes: bacilli (rod shaped), cocci (spherical), spirilla (spiral) Capsule and slim layers o Capsule: highly organized, firmly attached to cell wall o Slime layer: less organized, loosely attached to cell wall o Pilli: hair like structures on surface of bacteria which aid in attachment Helps anchor o Rotating flagella—a single cell that can swim. Can sense what is around them and swim (respond) A single cell can swim. Why would a bacteria cell want to swim. A bacterial cell would swim towards higher concentration of food source. A bacterial cell would swim away from too much concentration of sugar. When they swim towards something they want it is called positive taxis. Then you have all sorts of things they may swim towards such as a chemical this is called positive chemo taxis. The bacteria that does photosynthesis they want to move towards the light is called positive photo taxis. If there is too much radiation or light they will actually swim away from the light called negative photo taxis. Swimming away is negative taxis. Bacteria can sense the environment and know either to move away or go towards something or some way. o Endospore: protective “resting” structures, bacteria surrounded by durable cell wall. Resistant to extreme conditions Due to change in extreme conditions and expose thousands of structures
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There are places where they would survive and would survive an extreme meteor attack for example In each spore is all of the protein and genetic
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