During signal transduction fluctuations in the concentration

During signal transduction, fluctuations in the concentration of cytosolic calcium are controlled by Question 27 options: A. calmodulin and phospholipase C. B. gated Ca2+ channels and Ca2+-ATPase. C. parathyroid hormone and calcitonin. D. protein kinase and phosphoprotein phosphatase.

Solution

Reason:

Normally during, signal transduction through GPCR-receptors, fluctuations in the concentration of cytosolic calcium is controlled by Phospholipase-C. This is an enzyme that mediates selectively hydrolysis of phospholipid i.e. phosphatidylinositol 4,5-bisphosphate finally releases second messengers & calcium via activating IP3 (that acts on SER IP3 receptors) such as diacyl glycerol and IP3 (inositol 1,2-cyclic phosphodiester) finally another calmodulin protein also regulates cytosolic calcium.

In case of muscle contraction and relaxations, gated Ca2+ channels and Ca2+-ATPase on SER are playing meticulous role in controlling cytosolic calcium