BIO 201 Lecture Notes - Lecture 13: Symporter, Glut1, Conformational Change
11 Apr 2017
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Critically important for the function of all cells. Membrane lipids and membrane permeability: protocells had a variation of fatty acids as their membranes a. i. These membranes were amphipathic, so they formed spontaneously a. i. 1. For each polar head region, you only have one tail a. ii. 1. Density of tails it less than that of phospholipids a. ii. 1. i. As a result, these membranes are quite permeable a. ii. 2. i. This allows things like nucleic acids to enter directly into the cell: modern cells have phospholipid membranes b. i. Polar headgroup is more polar than that of fatty acids b. ii. The density of the membranes is a function of the saturation of the fatty acid tails of the phospholipids b. iii. Gaps in the membrane prevent fatty acid tails from packing together too tightly b. iv. 3. Modern cells have semi-permeable membrane: small polar and nonpolar compounds can pass through b. Simple diffusion directly through the membrane c. iii. Facilitated diffusion through a protein transporter c. iii. 1.
