[BLG 311] - Final Exam Guide - Ultimate 31 pages long Study Guide!

• School: Ryerson University
• Department: Biology
• Course: BLG 311
• Professor: Costin Antonescu

Document Summary

Membrane bilayer: the biological membrane is a bilayer (generally 5nm, biological membranes are generally composed by lipids and proteins. The main membrane lipids are: phospholipids, glycerophospholipids: uses glycerol for backbone, sphingophospholipids: uses sphingosine for backbone, sterols: help keep the membrane fluid consistent. The major types of phospholipids: glycerolphospholipids, phosphatidylethanolamine: head group has ethanolamine (positive charge) attached to the phosphate group (negative charge). Overall charge is neutral: phosphatidylserine: head group has serine. Overall charge is negative: phosphatidylcholine: head group has choline. Overall charge is neutral: not glycerophospholipid, sphingomyelin: contains phosphocholine and sphingosine in the head group. Overall charge neutral: sphingosine: overall charge is positive. Cholesterol is a major component of membranes: steroid ring is planar and rigid, the head group contains a hydroxyl group that is hydrophilic. This causes limitations of molecules entering; which decreases permeability. **membrane bilayer forms spontaneously and is a fluid structure**