ANP 1105 Lecture Notes - Lecture 2: Lipid Bilayer, Transmembrane Protein, Membrane Lipids
Document Summary
Phosphate heads: charged polar & hydrophilic; attracted to water. Fatty acid tails: uncharged nonpolar & hydrophobic; avoid water. Lipids with polar sugar groups on outer membrane surface. Includes a polar region (hydroxyl group) and nonpolar region (its fused ring system). The plasma membrane encloses cell contents, mediates exchanges with the extracellular environment, and plays a role in cellular communication. It separates two of the (cid:271)od(cid:455)"s (cid:373)ajor fluid (cid:272)o(cid:373)part(cid:373)e(cid:374)ts; the i(cid:374)tra(cid:272)ellular fluid (cid:894)(cid:449)ithi(cid:374) (cid:272)ells(cid:895) a(cid:374)d the extracellular fluid (outside cells). The fluid mosaic model is a fluid bilayer of lipids, consisting phospholipids, cholesterol, and glycolipids, with proteins inserted. Are firmly inserted into lipid bilayer; most are trans-membrane proteins that go through the entire membrane. Have hydrophobic and hydrophilic regions (can interact with lipid tails and water). Function is to transport proteins (channels and carriers), enzymes, or receptors. Includes filaments that help support the membrane from its cytoplasmic side.