BIOL2202 Lecture Notes - Lecture 1: Signal Transduction, Cell Membrane, Biological Membrane
Document Summary
Amphipathic molecules: hydrophobic tail, hydrophilic head. Functions of lipids structural: membrane components, protein modification. Other: cellular signalling, enzyme cofactors, electron carriers, pigments. Effects of double bonds smaller double bond ratio means lower melting point biological membranes. Define eternal boundaries of cells / intracellular compartments regulate traffic across this boundary functions: signal transduction, cell communication, complex reaction sequences, energy transduction special properties flexible, self-sealing/can fuse, selectively permeable, two-dimensional lipid aggregates. Heat disorder the interactions between the fatty acid tails to change the membrane from a gel to a fluid store. Long chain fatty acids aggregated extensively to give low fluidity gel-like. Short chain fatty acids less surface area to aggregate and increase fluidity. Unsaturated fatty acids aggregated less extensively and increase fluidity. Composition can also determine thickness, i. e. some molecules will become thicker when cholesterol is added. The relative size of the head group of the fatty acid determines curvature.
