KINE 304 Lecture Notes - Lecture 2: Garage Door, Aquaporin, Endocytosis
2 Mar 2017
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Document Summary
Structure and function of cells determined internal vs. external molecules. Movement of molecules dependent upon membranes and constituent proteins: molecules don"t stop moving when equal concentration is met. Molecules in constant state of motion but have tendency to reach equal level of concentrations. Diffusion: net movement of molecules from area of increased concentration to area of decreased concentration (net flux) Heat=things move faster: mass of molecule. Larger / slower than smaller: medium. Move fastest in gas medium liquid solid: surface area. Diffusion time increases by the square of the distance that must be traveled: *affect size of cells. Biological systems: membranes control internal vs. external concentration of molecules. Water and lipid base molecules easily cross membranes (lipid base membranes: *water passes through aquaporins, water follows solute. Membrane would be impermeable to polar and charged molecule, if not for proteins found in membrane (integral, transmembrane) How do polar and charged molecules cross membrane: channels.
