Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

8. Protein Function

Glycogen Phosphorylase

Biochemistry

8. Protein Function

Glycogen Phosphorylase

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Multiple Choice

The cleavage of glycogen by glycogen phosphorylase releases _____.

free glucose

UDP-glucose

glucose-6-phosphate

glucose-1-phosphate

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Verified step by step guidance

Understand the role of glycogen phosphorylase: Glycogen phosphorylase is an enzyme that catalyzes the breakdown of glycogen into glucose-1-phosphate by adding inorganic phosphate (Pi) to the terminal glucose unit of glycogen.

Recall the reaction mechanism: Glycogen phosphorylase performs phosphorolysis, not hydrolysis. This means it uses inorganic phosphate (Pi) to cleave the α-1,4 glycosidic bonds in glycogen, releasing glucose-1-phosphate instead of free glucose.

Recognize the product of the reaction: The immediate product of glycogen phosphorylase activity is glucose-1-phosphate, which is a phosphorylated form of glucose. This prevents glucose from freely diffusing out of the cell and keeps it available for further metabolism.

Understand the fate of glucose-1-phosphate: Glucose-1-phosphate can be converted into glucose-6-phosphate by the enzyme phosphoglucomutase, which is a key intermediate in glycolysis or other metabolic pathways.

Clarify why other options are incorrect: Free glucose is not directly released by glycogen phosphorylase, and UDP-glucose is involved in glycogen synthesis, not degradation. Glucose-6-phosphate is a downstream product formed after glucose-1-phosphate is processed.