BIO 1140 Chapter Notes - Chapter 5: Lipid Bilayer, Peripheral Membrane Protein, Fluid Mosaic Model
20 Feb 2014
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Document Summary
A membrane consists of proteins in a fluid made up of lipid molecules. Organisms can adjust the fatty composition of their membranes to resist temperature changes. Passive transport amphipathic molcules such as steroids and drugs small molecules such as h2o and glycerol (even though they are polar ~ they are small) diffusion drives passive transport. Atp is hydrolyzed in order for the substance to be moved across the membrane by the use of a pump eg; calcium pump - ca2+ conc is high inside er vesicles, and outside cells, but low in cell cytoplasm. 2 k+ in accumulation of + charge outside, so inside becomes negatively charged with respect to outside. Secondary active transport indirectly driven by atp uses gradient built by primary active transport in order to carry molecules through the membrane symport cotransported solute + ion move in same direction = cotransporter.
