Which of the Following is True of Microbes and Their

Question

Which of the following is true of microbes and their membranes?
A) They are relatively permeable to protons.
B) Protons can leak through directly when the difference in intracellular and extracellular pH is very high.
C) Membrane-permeant organic acids can prevent the leakage of protons.
D) They are able to change the pH optima of their enzymes.
E) Acidophiles use Na+/H+ antiporters to remove internal protons.

Accepted Answer

Microbes and their membranes are relatively impermeable to protons. However, when the difference in intracellular and extracellular pH is very high, protons may leak through directly. This is referred to as proton leakage, and it can lead to a decrease in energy efficiency for the microbe.