In: Biology
4. A culture of bacteria growing at 37°C was shifted to 25°C. How would you expect this shift to alter the fatty acid composition of the membrane phospholipids? Explain. If bacteria were able to synthesize cholesterol, how would you expect this shift to alter their membrane’s cholesterol concentration?
Whether the ambient temperature decreases, the permeability and fluidity of plasma membrane also decreases. This leads to the disruption of transportation of molecules across the plasma membrane. Therefore to restore back the normal permeability and fluidity level, more amount of unsaturated fatty acids are synthesized and incorporated into the membrane. This is because these fatty acids have double bond in them due to which they have a bended appearance. This bended appearance does not allowed them to pack tigthly with each other and therefore their presence makes the plasma membrane loose. This helps in restoring back the permeability to normal level.
If the bacteria is able to synthesise cholesterol, then the concentration of cholesterol will increase under low temperature. This is because cholesterol is a rigid plannar molecule which is the large in size. Its presence will also make the membrane permeable and fluid.
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