BSC 114 Lecture Notes - Lecture 6: Glycolipid, Signal Transduction, Phagocytosis
20 Sep 2016
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Plasma membrane- the boundary that separates a living cell from its surroundings: consist of phospholipid bilayers that are typically embedded with many proteins, other lipids, such as sterols, are also present in most plasma membranes o. Allow some substances to cross more easily than others. Phospholipids- amphipathic molecules containing hydrophobic fatty acid tails and hydrophilic head groups o. Positioned so the heads face the aqueous cytoplasm while the tails remain in the interior of the bilayer o. Rarely flip-flop transversely across the membrane: as temperature cools, membranes transition from a fluid state to a solid state. The temperature at which a membrane solidifies depends on its lipid composition. Membranes rich in phospholipids containing unsaturated fatty acids are more fluid than those rich in saturated fatty acids. Plasma membranes typically contain a collage of different proteins, often grouped together, embedded in the fluid matrix of the phospholipid bilayer o. Proteins determine most of a membrane"s specific functions.
