Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Tropic hormones act on other endocrine glands to stimulate the release of their hormones and transmit signalling through cell surface receptors. Reason (R): This action is attributed to their lipophilic nature. In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A) \
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A) \
• C. (A) is correct but (R) is not correct \
• D. (A) is not correct but (R) is correct

Hint:

Tropic hormones are protein molecules. Proteins are water-soluble (hydrophilic), meaning they always bind to receptors on the outside of the cell!

Answer 1

The Correct Option is C

Step 1: Concept Tropic hormones are signaling proteins secreted by the anterior pituitary gland (such as TSH, ACTH, LH, and FSH) that travel through the blood to trigger other endocrine glands to release their hormones.

Step 2: Meaning * Hydrophilic hormones are water-soluble proteins or peptides that bind to cell-surface receptors. * Lipophilic hormones are lipid-soluble steroids or iodothyronines that can cross cell membranes.

Step 3: Analysis * Assertion (A) is correct: Tropic hormones specifically target other endocrine glands (for example, TSH targets the thyroid gland) to stimulate hormone release. Because they are proteins or glycoproteins, they pass their signals through cell-surface receptors. * Reason (R) is incorrect: Tropic hormones are large, water-soluble peptides and glycoproteins. They are hydrophilic, not lipophilic, which is precisely why they must rely on cell-surface receptors rather than passing through the membrane.

Step 4: Conclusion Since the assertion is scientifically correct but the reason is false, option C is correct. Final Answer: (C)