30 Questions
What is the primary response that triggers glycogen degradation in skeletal muscle?
Exercise
What is the enzyme that catalyses the first step of glycogen degradation?
Glycogen phosphorylase
What is the product of the first step of glycogen degradation?
Glucose-1-phosphate
What is the purpose of the de-branching enzyme in glycogen degradation?
To produce free glucose
In muscle cells, what is the fate of glucose 6-phosphate produced during glycogen degradation?
It enters glycolysis
What is the difference between glycogen degradation in muscle and liver cells?
Glucose 6-phosphate is converted to glucose in liver cells
What is a common feature of glycogen storage diseases?
Tissue damage due to excessive glycogen storage
Which of the following is NOT a feature of glycogen storage diseases?
Increased muscle mass
Which tissues are most commonly affected in glycogen storage diseases?
Liver and/or muscle
What is the direction of the reaction in glycogen metabolism?
From glycogen to glucose
What is the byproduct of glycogen phosphorylation?
Pi
What is the high-energy molecule involved in glycogen synthesis?
UTP
What is the advantage of the highly branched structure of glycogen?
It allows for minimal osmotic effect in the storage tissue
What is the limitation of glycogen storage in tissues?
It is a highly polar molecule that attracts a lot of water
How much glycogen can the liver store?
Up to ~100g
What enzyme catalyzes the conversion of glucose to glucose-6-phosphate in the liver?
Glucokinase
What is the function of UTP in glycogen synthesis?
It is an important intermediate in the synthesis of sugar-containing molecules
What is the term for a group of clinical conditions characterized by abnormal storage of glycogen?
Glycogen storage diseases
What is the outcome of the catalyzed reaction involving glucose-6-phosphate?
Release of glucose into the bloodstream
What is the function of liver glycogen?
Storage of glucose that can be made available to all tissues
What type of control does glucagon and adrenaline promote on glycogen synthase and glycogen phosphorylase?
Phosphorylation
What is the effect of insulin on glycogen synthase and glycogen phosphorylase?
Dephosphorylation of both enzymes
What is the effect of phosphorylation on glycogen phosphorylase?
Activation
What is the relationship between glycogen synthase and glycogen phosphorylase when one is activated?
The other is inhibited
What is the primary source of glucose for some tissues?
Glycogen storage
What is the approximate duration after which glycogen storage is depleted?
8-12 hours
What type of bonds hold glucose residues together in glycogen?
Glycosidic bonds
What is the ratio of a1-4 to a1-6 bonds in glycogen?
10:1
What is the function of a1-6 bonds in glycogen?
They are the branch points
What is the process by which glucose is synthesized when glycogen stores are depleted?
Gluconeogenesis
Learn about the branched structure of glycogen, its role in glucose storage and removal, and its limitations in tissues. Understand how glycogen molecules are stored and their impact on osmotic effects. Discover the importance of glycogen in biological systems.
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