Which statement correctly describes the structure or function of cholesterol in the cell surface membrane?
It consists of a glycerol backbone esterified to three fatty acid chains.
It is positioned entirely within the hydrophobic core of the bilayer, containing no polar groups.
It helps maintain membrane fluidity at low temperatures by preventing tight packing of phospholipids.
It increases the permeability of the membrane to highly polar ions like sodium.
12 exam-style questions on OCR A A Level Biology Biological membranes. Each one has a worked solution and a mark scheme showing where the marks go.