Question

Which of the following alterations to a biological membrane would make it less fluid?

Increase the concentration of cholesterol in the membrane

Decrease the length of the fatty acid tails

Increase the number of cis bonds within the fatty acid tails

Replace select glycerophospholipids with sphingolipids

Glycosylate some of the peripheral proteins facing the extracellular aqueous environment

Answer 1

Increase the concentration of cholesterol in the membrane

-Membrane fluidity is function of its fatty acid and cholesterol content.

-Membrane fluidity can therefore be controlled by varying the number of double bonds and the length of fatty acids. Meanwhile, the presence of bulky cholesterol molecules within the membrane restricts fluidity.

-Cholesterol is key regulator of membrane fluidity in animals.

-Lipids rafts moderate membrane fluidity which causes membrane to be less fluid.