PSL201Y1 Lecture : Cell membrane and transport mechanisms A summary of the lecture about cell membranes, their properties, and descriptions of transport mechanisms in the cell membrane.
Document Summary
Cell membrane made of a dilipid layer, with proteins and channels in it to allow the movements of chemicals. Allows diffusion of gases and lipid-soluble molecules: lipids have a phosphate head and two fatty acid tails. Straight tail for strength, bent tail for flexibility. Head is hydrophilic, tails are hydrophobic: membrane stabilized by cholesterol. Membrane proteins are structural support for the cytoskeleton. Go through membrane and allow for channels, and can also act as receptors to signal molecules. The proteins criss-cross the membranes, like a needle and thread. On one end is nh2, on the other, Glycocalyx is a matrix of carbohydrate filaments in the extracellular space, anchored to the proteins (glycoproteins) or lipids (glycolipids). They slow diffusion and contain a net negative charge, attracting positive ions, calcium in particular. Channels are combinations of proteins to allow non-membrane permeable molecules in and out of the cell. Parts of it dangle in the cell, forming pore loops .
