LIFESCI 7A Lecture Notes - Lecture 2: Lipid Bilayer, Liposome, Amphiphile
Document Summary
Cells have diff shapes, intracellular contents, organization depending on their function within the body. Cells need membrane to distinguish itself from surroundings and be selective about what gets in and out. Most permeable | oxygen urea glucose na+ | least permeable. The steeper the concentration gradient, the higher the rate. Diffusion can occur whether or not a membrane is present. Inference: using observations ot make a guess about an outcome. Deduction: using general theories to make speci c claims or predictions. Phospholipid--made of glycerol backbone attached to phosphate group + two fatty acids. Phosphate head is hydrophilic, two fatty acid tails are hydrophobic. In aqueous environment, amphipathic molecules arrange themselves into structures w/ polar head groups on outside and nonpolar tails on inside. Bilayer forms spontaneously as long as concentration of phospholipids is high enough & ph of solution is similar to that of a cell (ph ensures head groups are in ionized form and thus hydrophilic)
