BIOL 1001 Chapter : Biol 1001 Chap5
Document Summary
>>>the cell membrane is usually the outermost barrier of the cell. An exception to this is found in cells which have a cell wall. The cell wall is mainly for structural support and protection. It usually doesn"t act as a barrier to molecules. The plasma membrane contains the cell but still allows the cell to interact with the environment. (see figs 5-1) The plasma membrane functions: isolate the cell environment, regulate exchange between inside and outside, communicate with other cells, identify the cell type plants - cellulose fungi - chitin bacteria - chitin plus proteins. The red blood cell has no internal membranes: biological membranes contain proteins. Evidence: membranes isolated from red blood cells contain proteins. Evidence: the phospholipid content of red blood cells is just enough to cover the cell with two layers: membranes are made of lipid, phospholipids are molecules which can form membranes naturally, cell membranes are phospholipid bilayers.
