Final answer:
Calcium ions (Ca²+) are released as the free cytoplasmic messenger in the calmodulin activation pathway, acting as a second messenger to modulate cellular activities.
Step-by-step explanation:
In the calmodulin activation pathway, the component released as a free cytoplasmic messenger is calcium ions (Ca²+). The process starts when G proteins activate the enzyme phospholipase C (PLC), which then catalyzes the formation of diacylglycerol (DAG) and inositol triphosphate (IP3).
IP3 binds to ligand-gated calcium channels in the endoplasmic reticulum, leading to the release of stored Ca²+ into the cytoplasm. Once in the cytoplasm, Ca²+ acts as a second messenger, either directly influencing cellular activities or by binding to proteins such as calmodulin, which modulates protein kinase activity within the cell, orchestrating numerous downstream responses.