BIOL 141 Lecture Notes - Lecture 12: Phospholipid, Hydrolysis, Aquaporin
27 Oct 2017
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Document Summary
Explain the four factors that influence the permeability behavior of a cell membrane. Describe how selective permeability influences the movement of solutes across membranes. Explain why movement by diffusion (and osmosis) is always passive. Apply the concept of osmotic movement of water to novel situations. Explain how the electrochemical gradient across the cell membrane is generated and how it is used to perform work by cells. Fluid mosaic model: the plasma membrane is more than just a bilayer. Contains phospholipids that move around within one leaflet (same side) Rare for one to flip to the other side because the hydrophilic head would have to go through the hydrophobic tails to get to the other side. When it does happen, the enzyme flipase helps. Diffusion: random movement of molecules from regions of high concentration. Diffusion: random movement of molecules from regions of high concentration to low concentration. Happens spontaneously, driven by entropy (highly ordered --> lower ordered)
