Answer:
E. Enzyme cleaves PIP2, forming DAG and IP3.
D. IP3 binds to a ligand-gated ion channel in the ER membrane.
A. Calcium ions flow through the ligand-gated ion channel.
C. Calcium ion concentration increases in the cytosol.
B. Calcium ions activate a protein, leading to a cellular response.
Explanation:
The enzyme phospholipase C which cleaves PIP2 into DAG and IP3 Is activated by the G protein once the histamine signaling molecule is received. IP3 moves to the cytosol to bond to IP3 gated calcium channel in the Endoplasmic reticulum membrane allowing for influx of Ca++ from the Endoplasmic reticulum membrane to the cytosol prompting a cellular response. The histamine's signal transduction pathway allows for amplification and regulatation of a signal at different points