Why must some hormones bind to a membrane receptor on a target cell's surface in order to activate it?
A) for activation by ATP
B) because they are not water-soluble
C) because they cannot cross cell membranes
D) to stimulate endocytosis to internalize the hormone

Question

Quizplus · Accepted Answer

Hormones that cannot cross cell membranes must bind to a membrane receptor in order to activate target cells. This is because the hydrophobic nature of cell membranes prevents hydrophilic molecules (such as hormones) from entering the cell. Therefore, membrane receptors act as a gateway for the hormone to interact with the cell's intracellular signaling pathways.

Why Must Some Hormones Bind to a Membrane Receptor on a Target