Question

Which of these is not a secondary messenger?

• A. cAMP
• B. cGMP
• C. Calcium
• D. Sodium/Mg

Answer 1

The correct option is D Sodium/Mg

Secondary messengers are intracellular signalling molecules released by the cell in response to exposure of extracellular signalling molecules-the first messengers. Second messengers trigger physiological changes such as proliferation, migration, survival, etc. Some common secondary messengers are cAMP(Cyclic Adenosine Mono Phosphate), cGMP(Cyclic Guanosine Mono Phosphate), Calcium ion, IP${}_3$, etc. So all the given options serve as secondary messengers except the Sodium/Mg ions.

So, the correct answer is 'Sodium/Mg'.