The ability of a cell membrane to allow hydrophilic molecules to pass into a cell is determined by:

A.	peripheral membrane proteins.
B.	integral membrane proteins.
C.	peripheral membrane carbohydrates.
D.	integral membrane carbohydrates.
E.	peripheral membrane lipids.

Tutorial

The diagram shows a complex of integral membrane proteins that make up the ATP synthase. Protons flow through a central protein channel, crossing the membrane, and in the process cause the membrane protein complex to catalyze the synthesis of ATP from ADP and Pi.