fyi, i\'ve seen several posts with this question, each with different choices. o
ID: 254071 • Letter: F
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fyi, i've seen several posts with this question, each with different choices. of the "fill in the blanks" that are the same, i've seen several different answersm so please help me & be thorough. i cant figure it out.
In muscle tissue, the ratio of phosphorylase a to phosphorylase b determines the rate of conversion of glycogen to glucose 1-phosphate Classify how each event affects the rate of glycogen breakdown in isolated muscle tissue. Increased rate Decreased rate No change addition of phosphorylase b kinase treatment with glucagon treatment with insulin addition of a phosphatase inhibitor addition of a kinase inhibitor Ca2 bindingt phosphorylase b kinase to removal of phosphate groups from phosphorylase a [ATP] exceeds [AMP]Explanation / Answer
Treatment with glucagon: This increases the rate of the glycogen breakdown. Glucagon activates the enzyme adenylate cyclase that converts ATP into cAMP which in turn activate protein kinase A. this kinase phosphorylate glycogen synthase rendering it inactive as well as phosphorylase kinase. This activated phosphorylase kinase phosphorylates glycogen phosphorylase making it active and triggering glycogen degradation.
Treatment with insulin: This decreases the rate of glycogen degradation. Insulin stimulates protein phosphatase-1 leading to dephosphorylation of glycogen synthase and phosphorylase kinase. Glycogen synthase increases the synthesis of glycogen. The phosphorylated phosphorylase kinase become inactive failing to activate glycogen phosphorylase.
Addition of phosphorylase b kinase: This will decrease the rate of glycogen breakdown. It is the inactivated form of the kinase and thus does not convert glycogen phosphorylase into its active state leading to inhibition of glycogen breakdown.
Addition of phosphatase inhibitor: This will increase the rate of glycogen breakdown. As the phosphatase will be inactivated and thus phosphorylase kinase will be activated leading to phosphorylation of the glycogen phosphorylase and thus the degradation.
Addition of a kinase inhibitor: This will decrease the rate of glycogen breakdown. As the kinase will be inactivated and thus the glycogen phosphorylase will not be phosphorylated rendering it inactive and thus no degradation.
Binding of Ca2+ to phosphorylase b kinase: It will increase the rate of glycogen breakdown. The phosphorylase kinase has a calmodulin subunit that binds to the calcium. The binding of calcium leads to the increase in activity of this enzyme to its substrate and enhances glycogenolysis, that is glycogen breakdown.
Removal of phosphate from phosphorylase a: It will decrease the glycogen breakdown as it makes the enzyme inactive and hence it cannot process glycogen.
ATP exceeds AMP: It will decrease glycogen breakdown as it will give out a signal that enough energy is present and there is no need of the process to happen.
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