When a steroid hormone and a polypeptide hormone exert similar effects on a population of target cells, then ________.
A) the steroid and polypeptide hormones must use the same biochemical mechanisms
B) the steroid and polypeptide hormones must bind to the same receptor protein
C) the steroid hormones affect the synthesis of effector proteins, whereas polypeptide hormones activate effector proteins already present in the cell
D) the steroid hormones affect the activity of certain proteins within the cell, whereas polypeptide hormones directly affect the processing of mRNA

Question

Quizplus · Accepted Answer

Steroid hormones typically act by altering gene expression, resulting in increased or decreased synthesis of proteins. Polypeptide hormones, on the other hand, typically act by activating existing effector proteins. Therefore, if both types of hormones have similar effects on target cells, it is likely that the steroid hormone is influencing the synthesis of a protein or proteins that already exist in the cell (thanks to the action of a polypeptide hormone), rather than directly activating effector proteins as polypeptide hormones do.

When a Steroid Hormone and a Polypeptide Hormone Exert Similar