Question

multiple choice question
what is the effect of glycerol on a plasma membrane at lower then physiological temperatures?

○ it makes the membrane less fluid.

○ it makes small openings in the membrane.

○ it disrupts lipid rafts.

○ it makes the membrane more fluid

Explanation:

To determine the effect of glycerol on a plasma membrane at sub - physiological temperatures, we analyze each option:

• Option 1: Glycerol does not make the membrane less fluid at lower temperatures. In fact, it has a stabilizing and fluid - enhancing effect in such conditions.
• Option 2: Glycerol does not create small openings in the membrane. Its action is related to membrane fluidity and stability, not pore formation.
• Option 3: Glycerol is not known to disrupt lipid rafts. Lipid raft disruption is caused by other factors like certain detergents or specific lipid - interacting molecules, not glycerol.
• Option 4: Glycerol acts as a cryoprotectant. At temperatures below physiological levels, it intercalates between lipid molecules in the plasma membrane. This interaction prevents the lipids from packing too closely together, which would otherwise occur due to the lower temperature and lead to decreased fluidity. By preventing tight packing, glycerol increases the fluidity of the plasma membrane.

Answer:

D. It makes the membrane more fluid (assuming the options are labeled A - D in the order given, with the last option being D)