Question

fill in the blank question
the plasma membrane maintains its fluidity at low temperatures due to the presence of \boxed{} molecules.

Explanation:

In cell biology, the plasma membrane's fluidity at low temperatures is maintained by unsaturated fatty acid chains in phospholipids or cholesterol. Cholesterol (or unsaturated fat - related molecules) helps prevent tight packing of phospholipids. The key molecule here is cholesterol (or unsaturated fatty acid - containing phospholipids, but cholesterol is a common answer for this concept).

Answer:

cholesterol (or unsaturated fatty acid - related, but cholesterol is the typical answer)