Biology - Chemical Coordination and Integration Question with Solution | TestHub
Which of the following statements about the mode of action of lipid soluble hormones is INCORRECT?
Options:
Answer:
Solution:
Lipid-soluble hormones (such as steroid hormones and iodothyronines) can easily pass through the cell membrane and bind to intracellular receptors.
The hormone-receptor complex then enters the nucleus and binds to specific regulatory sites on the DNA, thereby regulating gene expression or chromosome function.
The concept of a "first messenger" is associated with water-soluble hormones (like peptide and protein hormones) that bind to membrane-bound receptors and trigger the production of "second messengers" (such as cAMP, , ) inside the cell. Lipid-soluble hormones do not operate via the first/second messenger system.
Therefore, the statement that the hormone acts as the first messenger is incorrect for lipid-soluble hormones.
Answer: The hormone acts as the first messenger.
