Question

A major difference in the mechanism of action between steroid hormones and peptide hormone is that?
A. Steroid hormone does not affect the synthesis of protein whereas peptide hormones affect the activity of proteins already in the cell.
B. Target cells react more rapidly to steroid hormones than they do to peptide hormones.
C. Steroid hormone binds to a receptor protein whereas peptide hormones bind to G protein.
D. Steroid proteins affect metabolism, whereas peptide hormones affect the membrane permeability.

Answer 1

Steroid hormone main mode of action is usually done by activating genes and synthesis of enzymes bringing change in cell activity whereas in case of peptide hormone is done by protein enzymes by activating messengers.

Complete answer:
Steroid hormones do not affect the synthesis of protein whereas peptide hormones affect the activity of proteins in the cell. This is the true statement in context to the mechanism of action of both the hormones as in case of steroid hormone the receptor binds to promote the region of the responsive gene and it depends on the gene expression in the target cell.
The peptide hormone affects the activity of protein by acting on specific target tissue. Hence, it is the correct statement.
Target cells more rapidly in the case of peptide hormones due to presence of fast signaling transduction. So, B is a false statement.
Steroid hormone binds to the nuclear receptor not to the protein receptor. So, the C statement is also wrong.
Steroid proteins affect metabolism, whereas peptide hormones affect the membrane permeability that have no effect on mechanism of action. So, there is no relation in the action of mechanism with metabolism. D is also incorrect.

Hence, the correct answer is option (A).

Note: The hormone activity of the target cell is dependent on the effective concentration of the hormone receptor complex. And it also depends on the hormone composition. As the peptide hormone affects only the protein.