Question

At physiological temperature, sterols in biological membranes

• A. Increase their fluidity.
• B. Decrease their fluidity.
• C. Increase their permeability to water.
• D. Decrease their permeability to water.

Answer 1

The correct option is A Increase their fluidity.

Biological membranes are made up of lipid bilayer. These sterols affects the fluidity and rigidity of the membrane. At physiological temperature, sterols in biological membranes increases their fluidity but makes them more stronger and rigid. Environmental conditions like higher temperatures or unsaturated fatty disrupts close packing of lipids. This results in increase in the fluidity of the membrane. The membranes become more permeable to water. However, at lower temperatures, membranes become rigid.

Thus, the correct answer is option A.