BIOL 102 Lecture Notes - Lecture 11: Fluid Mosaic Model, Lipid Bilayer, Glycolipid

• School: Queen's University
• Department: Biology
• Course: BIOL 102
• Professor: Wayne Snedden

Document Summary

Membrane are mosaic of lipids, proteins and carbohydrates. Bilayer makes it hard for hydrophilic molecules to pass. Contain carbohydrates that are attached to lipids and proteins. Fluid mosaic model: membrane consists of lipid, protein, carbohydrate. Exhibit properties that resemble fluid: lipids/protein can move laterally to each other within membrane. Difference between leaflets occurs with glycolipids (lipids attached to carbohydrates: in extracellular leaflet, carbohydrates protrude (cell signaling) Move freely in 2-dimensions cells can change phospholipid composition of leafley. Move phospholipid from on leaflet to another. 3 proteins that can transfer: scramblases: transfer phospholipids along concentration gradient. Higher concentration leaflet lower concentration leaflet. No atp needed: flippases: move lipids form outer leaflet to inner, floppases: inner leaflet lower leaflet. Length of fatt acid tails: shorter acyl tails less likely to interact, more fluidiy. Unsaturated fats: (double bonds) in acyl tails: creates kink in tail, more difficult for tails to interact, more fluidity. Cholestrol: stabilizes membranes, depend on temperature.