Question

in chemical signaling, which of the following is considered to be a second messenger? ligand hormone g protein neurotransmitter cyclic amp i dont know yet

Explanation:

To determine the second messenger in chemical signaling, we analyze each option:

• Ligand: Molecules that bind to receptors (first messengers or initiators), not second messengers.
• Hormone: Can act as first messengers (extracellular signals), not second messengers.
• G protein: A membrane - associated protein that transmits signals from receptors to effectors, not a second messenger.
• Neurotransmitter: Transmits signals across synapses (first - messenger - like in their action at synapses), not second messengers.
• Cyclic AMP (cAMP): It is a well - known second messenger. When a ligand (first messenger) binds to a receptor, it can activate a G - protein - coupled receptor pathway, leading to the production of cAMP inside the cell. cAMP then relays the signal to downstream targets, so it functions as a second messenger.

Answer:

Cyclic AMP (the option with "Cyclic AMP" text)