The Biology Project > Cell Biology > Cell Signaling > Problem Set

Cell Signaling Problem Set

Problem 1: Receptors

A protein receptor binds a hormone outside the cell membrane and activates a protein kinase inside the cell. Is the receptor a peripheral or integral membrane protein?

A.	Membrane receptors are peripheral, or associated with the surface of the bilayer. Association with a hormone results in the release of a lipid signal that activates protein kinases.
B.	Membrane receptors associated with signaling are all integral membrane proteins that can transmit signals through the lipid bilayer. Yes, membrane proteins that function as receptors for cell signaling must penetrate the cell membrane. Since the polypeptide passes through the lipid bilayer, the protein-receptors are all integral membrane proteins.

The Biology Project > Cell Biology > Cell Signaling > Problem Set