Question

Why is a membrane made up of an unsaturated fatty acid bilayer more fluid than a bilayer composed of saturated fatty acids?

A. There is a stronger hydrophilic force betweent eh fatty acid tails of the unsaturated fatty acids.

B. There is more room for movement due to a lesser amount of van der Waals forces between the fatty acid tails

C. Unsaturated faty acids are not more fluid than saturated fatty acids.

D. The longer fatty acid tails have less hydrogen bonding.

Answer 1

The cell membrane fluidity is influenced by three factors:

a) Temperature, b) Cholesterol, and 3) Fatty acids

- The unsaturated fatty acid bilayer membrane is more fluid than a saturated fatty acid bilayer because in unsaturated fatty acids there are one or more double bonds and fewer hydrogens. Hence the double bonds introduce twists or curls in the hydrocarbon chain. The unsaturated fats will not pack into a regular structure and remain fluid at lower temperatures. Hence the right answer is option D.