Identify A, B and C in the diagramatic representation of the mechanism of hormone action. Select the correct option from the following. (A diagram of the mechanism of hormone action is shown, depicting a hormone binding to a membrane-bound receptor on the target cell, with labels A, B and C pointing respectively to the hormone, the receptor, and the intracellular signalling molecule generated; identify what each of A, B and C represents.)
Answer: (B) A-Protein Hormone, B-Receptor; C-Cyclic AMP. Answer: (b) A-Protein Hormone, B-Receptor; C-Cyclic AMP Solution: The diagram shows a hormone (A) binding to a membrane-bound receptor (B) on the target cell, generating an intracellular second messenger (C).
- A.A-Steroid Hormone; B-Hormone-receptor Complex, C-Protein
- B.A-Protein Hormone, B-Receptor; C-Cyclic AMP✓
- C.A-Steroid Hormone; B-Receptor, C-Second Messenger
- D.A-Protein Hormone; B-Cyclic AMP, C-Hormone-receptor Complex
Correct Answer
(B) A-Protein Hormone, B-Receptor; C-Cyclic AMP
Solution & Explanation
Answer: (b) A-Protein Hormone, B-Receptor; C-Cyclic AMP Solution: The diagram shows a hormone (A) binding to a membrane-bound receptor (B) on the target cell, generating an intracellular second messenger (C). Protein/peptide hormones do not enter the cell but bind membrane receptors and produce second messengers such as cyclic AMP. So A is a protein hormone, B is the receptor and C is cyclic AMP. NCERT Reference: Chapter 19, Page 248, Line(s) 10-12 — "Hormones which interact with membrane-bound receptors normally do not enter the target cell, but generate second messengers (e.g., cyclic AMP, IP3, Ca++ etc) which in turn regulate cellular metabolism"