BIO 3153 Lecture Notes - Lecture 5: Lipid Signaling, Fluid Mosaic Model, Lipid Bilayer
Document Summary
The plasma membrane is primarily composed of 2 components: lipids and proteins. Lipids give the membrane its basic fluid structure and provide a relatively impermeable barrier for the cell. Given enough time/energy/pressure anything can cross, but some are more likely. Phospholipids can be involved in cell signaling. Proteins give the membrane its mosaic characteristics, and mediate nearly all other functions of the membrane. Protein complexes allow transport in specific direction/certain times/amount of energy. Most abundant lipids in the membrane bilayer. This aids in organization in the cell. Presence of unsaturated double bond produces kink and influences fluidity of the membrane. Kinks also help with creating necessary spacing between phospholipids. Phospholipid molecules are quite mobile within their monolayer. Phospholipids change places with laterally adjacent phospholipids. Translocation from one layer to the other is rare and requires atp hydrolysis. Phospholipids changing places with phospholipids of the opposite layer. The flipping movement of the phospholipid requires atp.
