Glycogenesis and storage diseases

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What is the primary function of muscle glycogen?

To store glucose in animals

To regulate glycogen metabolism

To maintain blood glucose levels between meals

To serve as a fuel reserve for the supply of ATP during muscle contraction (correct)

What type of linkages hold glucose molecules together in glycogen?

α-1,4 and β-1,6

β-1,4 and β-1,6

β-1,4 and α-1,6

α-1,4 and α-1,6 (correct)

What happens to glycogen stores during fasting?

They remain constant

They increase

They are depleted (correct)

They are converted to protein

What is the percentage of glycogen stored in the liver?

6-8% Signup and view all the answers

What is the overall function of glycogen in animals?

To store glucose in animals Signup and view all the answers

What is the primary purpose of glycogenesis in liver and muscle?

To store excess glucose as glycogen Signup and view all the answers

Which enzyme is responsible for transferring the first glucose molecule to glycogenin?

Glycogen initiator synthase Signup and view all the answers

What is the carrier of glucose molecules during glycogenesis?

UDPG Signup and view all the answers

What is the name of the protein that can accept glucose from UDPG in the absence of a glycogen primer?

Glycogenin Signup and view all the answers

Which enzyme is responsible for synthesizing glycogen from glucose in liver and muscle?

Glycogen synthase Signup and view all the answers

What is the site of attachment of glucose from UDPG to glycogenin?

OH group of tyrosine residue of glycogenin Signup and view all the answers

What is the primary function of the branching enzyme in glycogen synthesis?

To transfer glucose residues from one chain to a neighboring chain Signup and view all the answers

What is the end product of liver glycogenolysis?

Glucose Signup and view all the answers

What is the role of phosphorylase in glycogenolysis?

To phosphorolytically split α-1,4 glucoside bonds Signup and view all the answers

What is the name of the enzyme that splits the α-1,6 linkages in glycogenolysis?

Amylo 1,6 glucosidase Signup and view all the answers

In which tissues does glycogenolysis occur?

In both liver and muscle Signup and view all the answers

What is the role of phosphoglucomutase in glycogenolysis?

To convert glucose-1-phosphate to glucose-6-phosphate Signup and view all the answers

What is the role of high cAMP levels in the regulation of glycogenesis and glycogenolysis?

It activates phosphorylase and inhibits glycogen synthase Signup and view all the answers

What is the effect of gluc-6-P on phosphorylase activity?

It inhibits phosphorylase Signup and view all the answers

What is the role of protein phosphatase in the regulation of glycogen metabolism?

It converts glycogen synthase a to glycogen synthase b Signup and view all the answers

What is the effect of adrenaline on glycogen metabolism?

It activates phosphorylase Signup and view all the answers

What is the role of insulin in glycogen metabolism?

It activates glycogen synthase Signup and view all the answers

What is the characteristic of glycogen storage diseases?

They are genetic diseases that result in the deposition of abnormal or increased quantity of glycogen Signup and view all the answers

What is the primary consequence of a block in gluconeogenesis in Von Gierke's disease?

Mobilization of fat to meet energy requirements Signup and view all the answers

Which enzyme is responsible for the accumulation of glycogen in lysosomes in all tissues, including muscles?

Lysosomal α-1, 4-glucosidase Signup and view all the answers

What is the consequence of accumulated glucose-6-phosphate in Von Gierke's disease?

Diversion to HMP pathway, leading to increased synthesis of ribose and nucleotides Signup and view all the answers

What is the primary reason for lactic acidemia in Von Gierke's disease?

Glucose is not synthesized from lactate produced in muscle and liver Signup and view all the answers

Which enzyme is responsible for the accumulation of polysaccharide with few branch points?

Debranching enzyme Signup and view all the answers

What is the consequence of massive liver enlargement in Von Gierke's disease?

Cirrhosis of the liver Signup and view all the answers