An E. coli culture that has been growing at 37°C is moved to 25°C. Which of the following changes must be made in its plasma membrane?
A) The number of saturated chains must increase.
B) The number of phosphate groups must increase.
C) The viscosity must increase.
D) The number of unsaturated chains must increase.
E) No changes are necessary.

Question

Quizplus · Accepted Answer

In order to maintain an appropriate level of fluidity and permeability, the E. coli culture must increase the number of unsaturated chains in its plasma membrane when its temperature is lowered from 37°C to 25°C. Unsaturated chains have kinks caused by cis double bonds that prevent them from packing tightly with neighboring chains, making them more fluid at lower temperatures. This helps to maintain membrane function and prevent damage.

An E Coli Culture That Has Been Growing at 37°C Is