A molecule is applied to a cell and the intracellular Ca2+ concentration is found to transiently rise. You are curious to understand the mechanism of this molecule so you remove all of the Ca2+ from outside the cell but find that the same effect is observed. You conclude that the molecule is probably having this effect because it sets into motion a chain of events that includes…

A. activation of adenylyl cyclase.
B. increasing the intracellular concentration of cAMP.
C. activation of phospholipase C.
D. blocking the Na+/K+ pump.
E. activation of a phosphodiesterase.

The correct answer is option C.

Explanation:

Phospholipase C comes in the category of membrane-associated enzymes, which plays an essential role in the cell physiology of eukaryotes, mainly in the process of signal transduction. One of the general features of the phospholipase C pathway is that it enhances the concentration of calcium within the cell's cytoplasm.  

With the stimulation of phospholipase C within a cell, calcium generally gets discharged from the intracellular compartments, which eventually results in the upsurge of calcium levels within the cell's cytoplasm.  

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products