General Structure And Functions Of The Plasma Membrane

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General structure and functions of the plasma membrane

The plasma membrane acts as the partition between the cell and its exterior environment. It is made out of a bilayer of phospholipids with proteins and cholesterol embedded. The phosphatidylcholine is the most common phospholipid in cell membranes and is made out of a glycerol backbone to which a choline-phosphate group is attached to and two fatty acid tails (Alberts, 2009). The bilayer also contains cholesterol to maintain the fluidity of the membrane, which can also be enhanced or reduced depending on the amount of unsaturated fatty acid chains. The double carbon bond causes a kink in the chain which increases the fluidity of the membrane (Brooker, 2013). The proteins embedded to the
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These proteins regulate most of the membrane’s functions including the main,which is the control of entry and exit of different molecules, ions and water, however the plasma membrane has several other roles contributing to the coordination of an organism. For example, transmembrane proteins have a few functions, which include the attachment to the cytoskeletal filaments of the cell, which restricts movement of those proteins. This is particularly important for the maintenance of the protein structure of an erythrocyte. The cytoskeleton of the red blood cell is formed from a hexagonal lattice of spectrin protein which has 4 subunits, with actin filaments at the connections. This cytoskeleton is linked to macro-complexes, which are made out of the interactions of transmembrane proteins and cytoskeletal proteins. The disruption of this can cause changes in the structure of the erythrocyte and …show more content…
This allows maximisation of efficiency of those reactions by concentrating metabolites and enzymes in a small, well defined space of the cell. These are tightly managed by lipid membranes, which are different to the phospholipid bilayers. (Finean, Coleman and Michell, 1984) An example of compartmentalisation or so called spatio-temporal regulation can be the way in which second messengers are aligned in the cell to allow efficient reactions. The 4 most studied second messengers are cAMP, cGMP, NO and Ca2+ .(McCormick and Baillie,

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