Question

You have just discovered an organism that lives in extremely cold environments. Which of the following would you predict to be TRUE about the phospholipids in its membranes, compared to phospholipids in the membranes of organisms that live in warmer environments?
a) The membrane phospholipids of cold-adapted organisms will have longer hydrocarbon tails.
b) The membrane phospholipids of cold-adapted organisms will have more saturated hydrocarbon tails.
c) The membrane phospholipids of cold-adapted organisms will have more unsaturated hydrocarbon tails

Answer 1

Answer:

c) The membrane phospholipids of cold-adapted organisms will have more unsaturated hydrocarbon tails

Explanation:

The cell membranes are fluid, the lipids that compose it have some movement. In cold temperatures that movement is reduced and the membrane becomes more rigid. To overcome this, organisms that live in cold environments have certain adaptations that keep the membrane fluid.

One of those adaptations is to contain more unsaturated phospholipids. Unsaturated phospholipids contain double bonds that introduce “kinks”  in the hydrocarbon tails, which interfere with the lipid's packing and reduce rigidity.