Question

______ is the ligand (signal) for IP3-gated Ca2+ channels on the ER (contains a high conc of calcium).

a) ATP
b) cAMP
c) IP3
d) GTP

Answer 1

The ligand for IP3-gated Ca2+ channels on the ER is IP3. IP3 binds to receptors on the ER, opening Ca2+ channels and allowing stored Ca2+ to flood the cytosol.

Step-by-step explanation:

The ligand (signal) for IP3-gated Ca2+ channels on the ER, which contains a high concentration of calcium, is IP3 (c). When IP3 binds to receptors on the smooth endoplasmic reticulum, it opens Ca2+ channels, allowing stored Ca2+ to flood the cytosol. This release of Ca2+ from the ER triggers various cellular responses.