Question

Which is the correct sequence of hormone action through membrane receptors?
I. Physiological responses e.g. ovarian growth.
II. Generation of secondary messenger.
III. Release of an enzyme adenylate cyclase from the receptor site.
IV. Formation of hormone receptor complex e.g. FSH.
V. Biochemical responses

• A. I - II - III - IV - V
• B. I - II - V - III - IV
• C. IV - III - II - V - I
• D. IV - V - II - III - I

Hint:

Protein hormones bind membrane receptors, activate adenylate cyclase, form cAMP, cause biochemical changes and then a physiological response.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
Protein hormones like FSH cannot enter the cell, so they act through receptors on the cell membrane.

Step 2: Order of events
IV: the hormone binds the receptor to form a hormone-receptor complex.
III: the complex activates adenylate cyclase.
II: a second messenger (cyclic AMP) is generated.
V: biochemical responses occur.
I: the physiological response, such as ovarian growth, appears.

Step 3: Conclusion
The sequence is IV, III, II, V, I.

Final Answer:
The sequence is IV - III - II - V - I. \[ \boxed{\text{(C) }\text{IV - III - II - V - I}} \]