Question

3. Many membrane process such as transport or signal transduction depends on the fluidity of lipids membrane. How fatty acids and cholesterol effect the fluidity of the membrane.

Answer 1

Here the fluidity of membrane is indicated interms of viscosity.Biological membranes are generally made up of phospolipids,cholesterol,proteins etc.Lipid packing influence the fluidity of membranes.Heat energy influences membrane permeability and its fluidity by affecting the nature of lipids and cholesterol.Here phospolipids are made up of varying lengths of fatty acids and saturation.Long hydrocarbon chain act as hydrophobic end and acid side act as hydrophilic end.Both saturated and unsaturated carbon chains affects the fluidity upon temperature variations.Lipids with unsaturated are more fluidity than lipids with saturated.Lipids with short chains are less stiff and less viscous.

Cholesterol is biomolecule that synthasised from fatty acids.It act as a bidirectional regulator of membrane fluidity because at high temperatures it stabilizes the membrane by elevating the melting point of membranes where as at low temperatures it intercalates between phospolipids prevents them from clustering and stiffening