41 Questions
What is the byproduct of the reaction catalyzed by glycogen synthase?
UTP
What is the coenzyme required by glycogen phosphorylase?
Pyridoxal phosphate
What is the enzyme deficiency that affects glycogen storage and metabolism?
All of the above
What is the substrate for glycogen synthase?
UDP-Glucose
What is the product of glycogen phosphorylase?
Glucose-1-phosphate
What is the disease associated with Glucose transporter-2 deficiency?
Fanconi-Bickel disease
What is the enzyme that converts Glucose 6-phosphate to Glucose 1-phosphate?
Phosphoglucomutase-1
What is the precursor used in the gluconeogenesis route to produce glucose-6-phosphate?
Alanine and lactate
What is the end product of glycogen phosphorylase?
Glucose 1-PO4
What is the function of phosphoglucomutase in the glycogenolysis pathway?
Converts Glucose 1-PO4 to Glucose 6-PO4
Where does dephosphorylation of Glucose 6-PO4 occur?
Liver only
What is the purpose of branching enzyme in glycogen synthesis?
Transfers a part of the α-1,4 chain to an adjacent chain to form an α-1,6 linkage
What is the limitation of glycogen phosphorylase?
It cannot act on the last 4 glucose units
Why does glycogen phosphorylase require a transferase enzyme?
Because it cannot act on the last 4 glucose units
What is the purpose of glycogen synthase in glycogen synthesis?
Adds glucose molecules to the glycogen chain via α-1,4 glycosidic bonds
What is the result of the further addition of α-1,4 glucosyl units and further branching in glycogen synthesis?
A multi-branched structure
What is the effect of phosphorylation on glycogen synthase?
Inactivation
What is the role of phosphatases in glycogen synthesis?
Activation of glycogen synthase
What is the effect of glucose-6-phosphate on glycogen synthase activity?
Stimulation
What is the effect of increased glycogen concentration on glycogen synthase activity?
Inhibition
What is the role of glycogen synthase kinase in regulating glycogen synthase activity?
Inhibitor
What is the role of 5’AMP-Activated Protein Kinase (AMPK) in regulating glycogen synthase activity?
Kinase
What is the role of Glycogen-Targeting Protein (GM Protein) in regulating glycogen synthase activity?
Phosphatase
What is the effect of insulin on glycogen synthesis?
Stimulation
What happens when protein kinase phosphorylates phosphorylase kinase B?
It leads to the activation of glycogenolysis
What is the effect of insulin on cAMP synthesis?
It decreases cAMP synthesis
What triggers cAMP-independent activation of glycogenolysis in the liver?
Epinephrine and norepinephrine
What activates calcium calmodulin-sensitive phosphorylase kinase?
Calcium mobilization
What is the effect of phosphorylase A inactivation?
It decreases glycogenolysis
What can activate cAMP-independent glycogenolysis in the liver?
Epinephrine, norepinephrine, vasopressin, oxytocin, and angiotensin
What is the result of alpha-adrenergic receptor activation in the liver?
Activation of glycogenolysis
What is the effect of phosphodiesterase activity on glycogenolysis?
It decreases glycogenolysis
What is the effect of insulin on phosphorylase B?
It indirectly inhibits the activation of phosphorylase B
What happens to glycogenolysis when phosphorylase kinase is inhibited?
It decreases
What is the effect of cAMP on phosphorylase kinase?
It activates phosphorylase kinase
What is the effect of ATP on phosphorylase kinase B in muscle?
It inhibits phosphorylase kinase B
What is the effect of glucose 6-phosphate on protein phosphatase?
It activates protein phosphatase
What is the effect of cAMP on protein phosphatase?
It inhibits protein phosphatase
What is the effect of insulin on glycogenolysis?
It decreases glycogenolysis
What is the effect of glucose 6-phosphate on glycogenolysis?
It decreases glycogenolysis
What is the effect of phosphorylase kinase on glycogenolysis?
It increases glycogenolysis
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