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biolexam2notes - Biology 1001 Chapt. 4 Wed. 2/10-2/12/10...

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Biology 1001 Chapt. 4 Wed. 2/10-2/12/10 How do substances move across membranes? Transport Process 1. Passive transport : movement down concentration gradient; no E required a. Simple diffusion : goes across membrane without help b. Facilitated : (high concentration to low concentration till equal) Diffusion : goes across membrane with help c. Osmosis : water moves through differently permeable membrane Diffusion high to low concentration ( no energy used) 1. All molecules constantly vibrating (stops vibrating at 273 degrees Celsius) 2. Those in gas and liquid move randomly 3. Mixtures tend to become uniform a. Ex. Dye in water spreads through water until entire mixture is homogenous Osmosis diffusion of water across differentially permeable membrane Energy Requiring Transport movement against concentration gradient; requires E (low concentration to high concentration) a. Active transport: movement via membrane- spanning proteins (ATP helps process) b. Endocytosis : move large particles in (eating) c. Exocytosis : moving materials out (pooping) Endo-Exocytosis 1. This is like cell eating and pooping 2. Active process for large groups of molecules a. Endocytosis- engulfment (pinocytosis (pinch), receptor-mediated (specific) phagocytosis (feet wrap around food and engulf it) b. Exocytosis- expulsion ________ can readily diffuse across a lipidbilayer. CO2
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This note was uploaded on 03/03/2010 for the course BIOL 001 taught by Professor Pollock during the Spring '10 term at LSU.

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biolexam2notes - Biology 1001 Chapt. 4 Wed. 2/10-2/12/10...

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