Biology 1002B Lecture Notes - Lecture 7: Membrane Protein, Cytoskeleton, Exocytosis
Document Summary
Plasma membrane: selectively permeable, allowed for the of waste membranes have come more complex barrier uptake of key nutrients and elimination, protected environment in which metabolic processes can occur. Internal membranes: allowed for compartmentalization of processes and increased complexity, ex. nuclear envelope. Consist of fluid lipids in which proteins are embedded and float freely. Lipid molecules exist in a double layer. Called bilayer that is less than 10nm. Molecules vibrate, flex back and forth, spin around their long axis, move sideways and exchange places within the same bilayer half. Anchor cytoskeleton filaments to the membrane and thus do not move. Have carbohydrate groups linked to them, forming glycolipid and glycoproteins. Proportions of lipid and protein vary depending on type of membrane. Ex. inner mitochondrial membrane lots of proteins for etc. Ex. plasma membrane - contains equal protein and lipid amounts. Ex. external membrane hormones and glycolipids and carbohydrate groups.
