Question

Cholesterol mixes with phospholipids in a biomembrane because cholesterol molecules are:

1) Steroid derivatives
2) Amphipathic
3) Entirely hydrophobic
4) Phospholipid derivatives

Answer 1

Cholesterol molecules are amphipathic, which allows them to mix with phospholipids in the biomembrane, contributing to its fluidity and stability.

Step-by-step explanation:

Cholesterol mixes with phospholipids in a biomembrane because cholesterol molecules are amphipathic. Like phospholipids, cholesterol has a structure that is part hydrophilic and part hydrophobic. The cholesterol molecule includes a polar -OH group (the hydrophilic 'head') and a cholestane structure (the hydrophobic 'tail'), allowing it to interact with the hydrophilic phosphate heads and the hydrophobic fatty acid tails of the phospholipids in the membrane. This amphipathic nature contributes to the fluidity and stability of the biomembrane, where cholesterol and phospholipids work together to create a flexible yet structurally coherent barrier.