BIO130H1 Final: exam readings part1.docx

• School: UTSG
• Department: Biology
• Course: BIO130H1
• Professor: Kenneth Yip

Document Summary

Plasma membrane: enclose cell, define boundaries, maintain essential differences between cytosol & extracellular environment, eukaryotic cell. Membranes of membrane-enclosed organelles (e. g. er/ golgi apparatus/ mitochondria) Maintain characteristic differences between contents of each organelles & cytosol. Ion gradients across membranes established by activities of specialized membrane proteins used to synthesize atp drive transmembrane movements of selected solutes: nerve/ muscle cell. Proteins -> sensors of external signals allow cell to change behavior in response to environmental cues (e. g. signals from other cells: all membranes in common. Very thin film of lipid & protein molecules. Lipid (arranged as continuous double layer about 5nm thick membrane proteins embedded: 2d liquid constituent molecules free to move laterally, 50% mass of membrane, lipid bilayer. Relatively impermeable barrier to passage of water-soluble molecules: all molecules are amphiphilic. Hydrophobic: most abundant membrane lipids- phospholipids. 1 polar head group + 2 hydrophobic hydrocarbon tails (14- 24 c) One tail with 1+ cis-double bonds unsaturated, one saturated.