Question

1a.

Cholesterol is not used for which of the following:

		Making the membrane less fluid
		Making the membrane more fluid
		Bile acids and salts synthesis
		Steroid hormone synthesis

1b.

In which part of a membrane would cholesterol be found?

		Covalently attached to the polar head groups of the phospholipids.
		Bound to peripheral protein molecules.
		Embedded in the fatty acid layer in the middle of the lipid bilayer.
		Attached to the cytoplasmic domain of integral membrane proteins.

Answer 1

1(a) for making the membrane more fluid.

The cholesterol decreases fluidity of the membrane as it attaches with lipid chains of the phospholipid. It stabilizes the membrane due to its ringed structure and increases theelting point.

1(b) Embedded in the fatty acid layer in the middle of the lipid bilayer. The cholesterol has carbon rings , fatty chains which react with fatty chains of phospholipi, and have a -OH head which is attracted towards polar head of phospholipid.