CHAPTER FOUR

CHAPTER FOUR - CHAPTER FOUR Cell-basic most simplified form...

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CHAPTER FOUR Cell -basic most simplified form of life. Cell will act as a compartment which can separate the external from the internal environment homeostasis(constant environment). The Cell Theory -(characteristics)-the fundamental unit of life. All organisms are formed or composed of many cells. All cells come from pre-existing cells. Pasteur-experiments with flask, conclusion-all life comes from existing life. Cell size (limited)-you want lots of biochemical reactions/metabolic activities=very large! Mostly for absorption (small). Ex). Egg-lots of metabolic activity-large, Sperm-small To increase surface area-flatten cell. Microvilli/villi -greater surface area Ex). Lining of digestive tract (to absorb nutrients). Microscopes 1. Light-uses glass lens to focus visible light, has resolution power of about 0.2 micrometers (mM)-Ex). Organelles 2. Electron-magnets that focus an electron beam, allows you to see things much smaller about .5mM Ex). Chemical Reactions Plasma membrane-phospholipid-selectively permeable barrier, made of lipid bilayer and proteins (can be attached to sugars or carbs). Only allows certain things in and out! Functions: Selectively permeable, receive information from close by cells & receive info from chemical signals, allow cell to maintain constant internal environment, allows one cell to bind/adhere to another cell. Ex). Skin cells Prokaryotes Microbes(very small) No nucleus Membrane bound-no organelles
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Find in extreme heat, salts, and acidic environments Generally smaller Single-celled Nucleotide-DNA region is here Cytoplasm-fluid & components found in membrane, contains proteins & ribosomes Plasma membrane-a little different, cell wall outside plasma membrane Peptideoglyogen-antibiotics attack Polysaccharide Cyanobacteria-extremly important can do photosynthesis, their membrane is highly folded-allowing a greater surface area for photosynthesis. Eukaryotes Membrane enclosed nucleus Specialized-many have flagella-structure for locomotion, corkscrew shape will Usually have multiple flagella Pili-threadstructure which allows one bacteria to attach to another bacteria. Capsule around outside of cell wall made of carbs. Interferes with harmful pathogen recognition
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This note was uploaded on 09/13/2009 for the course BIO 120 taught by Professor Ander... during the Fall '08 term at Detroit Mercy.

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CHAPTER FOUR - CHAPTER FOUR Cell-basic most simplified form...

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