Question

Cholesterol increases permeability for small polar molecules, increases permeability for Ca₂⁺, buffers membrane fluidity by increasing fluidity at low temperature and decreasing fluidity at high temperature, and is found in abundance in prokaryotic cell membranes. Which of the following statements about cholesterol is correct?

1) Increases permeability for small polar molecules.
2) Increases permeability for Ca₂⁺.
3) Buffers membrane fluidity by increasing fluidity at low temperature and decreasing fluidity at high temperature.
4) Is found in abundance in prokaryotic cell membranes.
5) All of the above are correct.

Answer 1

Cholesterol increases permeability for small polar molecules and Ca2+ ions and buffers membrane fluidity. It is also found in abundance in prokaryotic cell membranes.

Step-by-step explanation:

Cholesterol has several functions in the cell membrane. It can increase permeability for small polar molecules and Ca₂⁺ ions. Cholesterol also acts as a buffer for membrane fluidity, increasing it at low temperatures and decreasing it at high temperatures. Furthermore, cholesterol is found in abundance in prokaryotic cell membranes.