Question

16 A) DAG activates:

calmodulin.

PKA.

PKC.

PLC.

16 B) In muscle, glycogen phosphorylase kinase can be activated by nerve stimulation even in the absence of hormonal signals. Nerve stimulation alone results in activation of glycogen phosphorylase kinase as a result of:

elevated cytosolic Ca2+.

None of the answers is correct.

phosphorylation by cAMP dependent PKA.

All of the answers are correct.

Answer 1

Ans. DAG (Diacylglycerol) is a signalling molecule that activates cytosolic enzyme PKC (protein kinase C) and translocates it to plasma membrane from cytosol.

Hence, the correct answer is PKC.

Ans. Nerve stimulation, muscle contraction, and hormones increase intracellular (cytosolic) calcium ion concentration. Activation of glycogen phosphorylase kinase by nerve stimulation is also resulted from elevated cytosolic calcium ion concentration.

Hence the correct answer is elevated cytosolic Ca²⁺.