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Unformatted text preview: 1 http://www.guidesbyjulie.blogspot.com AP Biology Class Notes from January 22-23 on Prokaryotes PROKARYOTES I. I. I. I. Overview Overview Overview Overview A. Earliest organisms- evolved alone for 1.5 billion years. B. Still dominate the biosphere C. Thrive everywhere-too hot, too cold, too salty, too acid or base for eukaryotes D. Usually only hear about disease-causing E. More beneficial than harmful Example: intestinal bacteria; chemical recyclers F. Prokaryotes live together and with other organisms in symbiotic relationships G. Diverse in structure and metabolism H. 5,000 known species- probably really 400,000 to 4 million species II. II. II. II. 2 Main Branches: A 2 Main Branches: A 2 Main Branches: A 2 Main Branches: Archaea and Bacteria rchaea and Bacteria rchaea and Bacteria rchaea and Bacteria A. These 2 are fundamentally different B. 2 domains C. Archaea different: extreme environments; differ on structure, biochemistry and physiology III. III. III. III. Structure, Function and Reproduction Structure, Function and Reproduction Structure, Function and Reproduction Structure, Function and Reproduction A. Intro 1. Unicellular 2. Some aggregate to form colonies 3. Shapes: cocci, bacilli, helices (spirochetes) 4. Size: 1-5 micrometers for most B. Most have cell wall and cell membrane 1. Maintains shape; protects; prevents plasmolysis. 2. Most have peptidoglycan- Archaea Archaea Archaea Archaea dont dont dont dont 3. Gram Stain- tool to identify (stain walls) a) Gram-positive: simpler with lots of peptidoglycan- pick up strain b) Gram-negative: more complex and less peptidoglycan, have lipopolysaccharides 4. Gram-negative more pathogenic - lipopolysaccharides toxic and allow for resistance to antibiotics 5. Antibiotics function by preventing cross-link in peptidoglycan walls 6. Some have cell capsule outside wall 7. Some have pili a. Adhere to host cell b. Used for conjugation C. Motility 1. Half can move 2 http://www.guidesbyjulie.blogspot.com AP Biology Class Notes from January 22-23 on Prokaryotes 2. Use flagella-on entire surface or at one end 3. Different from eukaryotes 4. Spirochetes mechanism- cell moves like corkscrew 5. Other- secretion of slimy threads anchoring cells (gliding)...
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This note was uploaded on 01/19/2012 for the course CH 101 taught by Professor Sutcliffe during the Spring '08 term at University of Texas at Austin.
- Spring '08
- AP Biology