24 Questions
What is the enzyme responsible for adding orthophosphate to cleave glycogen?
Glycogen Phosphorylase
Which enzyme is involved in attacking the a-1,4 linkages during glycogenolysis?
Glycogen 1-phosphorylase
What is the role of debranching enzymes in glycogenolysis?
Transferring glucose residues from a-1,6 to a-1,4 linkages
What is the final product formed after the removal of the glucose molecule from the a-1,6 linkage?
Glucose 1-phosphate
Which enzyme is responsible for converting glucose 1-phosphate into glucose 6-phosphate?
Phosphoglucomutase
Explain the role of Glycogen Phosphorylase in glycogenolysis.
Catalyzes the cleavage of glucose from glycogen by adding orthophosphate.
What is the function of Glycogen 1-Phosphorylase in glycogenolysis?
Attacks the a-1,4 linkages in glycogen until it reaches the a-1,6 linkages.
Describe the mechanism of action of debranching enzymes in glycogenolysis.
Transfers 3 glucosyl residues from the a-1,6 linkage to the a-1,4 linkage and hydrolyzes the final glucose molecule.
How does phosphoglucomutase participate in glycogenolysis?
Converts glucose 1-phosphate into glucose 6-phosphate.
Explain the significance of glucose 6-phosphate in glycogenolysis.
Can be directly metabolized and is an essential intermediate in glucose metabolism.
What enzyme in the liver is responsible for converting glucose 6-phosphate into glucose when needed by the body?
Glucose 6-phosphatase
How is Glycogen broken down in muscles for anaerobic glycolysis?
Glycogen phosphorylase
What activates phosphorylase b in muscles and inhibits phosphorylase a?
AMP activates phosphorylase b, while ATP inhibits it.
Which hormone triggers the conversion of phosphorylase from its inactive form (b) to the active form (a)?
Adrenaline/Epinephrine and glucagon
What is the role of Ca2+ in the regulation of glycogen breakdown in muscles?
Ca2+ activates phosphorylase a, stimulating glycogen breakdown.
How is the signal for glycogen breakdown turned off in muscles?
By dephosphorylating phosphorylase a to b.
What triggers the conversion of phosphorylase b to a in muscles?
High Ca2+ levels
Which subunit of phosphorylase kinase acts as the Ca2+ sensor?
Delta
What inhibits phosphorylase a in muscles?
Low ATP
Which hormone triggers the conversion of phosphorylase b to a?
Epinephrine
What role does protein phosphatase 1 play in glycogen breakdown regulation?
Converts phosphorylase a to b
In muscles, what activates phosphorylase kinase besides Ca2+?
AMP
What is the main factor that turns on phosphorylase b to a in muscles?
Low ATP and High AMP levels
What activates phosphorylase kinase by binding to the GPCR?
Cyclic AMP (cAMP)
Test your knowledge on the process of breaking down stored glycogen into glucose through glycogen phosphorylase and debranching enzymes. Learn about the cleavage of glycogen by the addition of orthophosphate and the role of different enzymes in this process.
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