Question

GPCRs are sometimes referred to as "seven-pass transmembrane receptors" for which reason? Choose one:

A. There are seven different G proteins with which they interact to amplify signals.
B. They form seven pores through which signal molecules can cross the lipid bilayer.
C. They are composed of seven distinct subunits arranged in a ring. D. Their polypeptide chain crosses the lipid bilayer seven times.
E. . They bind to seven extracellular signal molecules before passing a message to the cell interior.

Answer 1

D. Their polypeptide chain crosses the lipid bilayer seven times. GPCRs are referred to as 'seven-pass transmembrane receptors' because their polypeptide chain crosses the lipid bilayer seven times. This allows them to interact with G-proteins and activate intracellular signaling pathways.

Step-by-step explanation:

G-protein-coupled receptors (GPCRs) are called 'seven-pass transmembrane receptors' because their polypeptide chain crosses the lipid bilayer seven times.

These receptors have seven transmembrane domains, which are regions of the receptor that go through the cell membrane.

These transmembrane domains allow GPCRs to interact with G-proteins and activate intracellular signaling pathways in response to binding with a ligand.