Question

For the action of hydrophilic hormones, second messengers are generated only when the hormone binds to cell surface receptors.

• A. True
• B. False

Answer 1

The correct option is A True

Hormones that are too large or too polar to cross the plasma membranes of their target cells bind to receptor proteins located on the outer surface of the plasma membrane—the hormones do not enter the cell. The interaction between the hormone and its receptor activates mechanisms in the plasma membrane that increase the concentration of the second messengers within the target cell cytoplasm.