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

Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway

Pentose Phosphate Pathway

Biochemistry

Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway

Pentose Phosphate Pathway

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Multiple Choice

In the pentose phosphate pathway, which enzyme catalyzes the first committed step, resulting in the production of 6-phosphoglucono-δ-lactone from glucose-6-phosphate?

Aldolase

Transketolase

Phosphoglucomutase

Glucose-6-phosphate dehydrogenase

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Verified step by step guidance

Understand the pentose phosphate pathway: This metabolic pathway is crucial for producing NADPH and ribose-5-phosphate, which are essential for biosynthetic reactions and nucleotide synthesis, respectively.

Identify the first committed step: The first committed step is the irreversible reaction that commits glucose-6-phosphate to the pentose phosphate pathway. This step is catalyzed by the enzyme glucose-6-phosphate dehydrogenase.

Describe the reaction: Glucose-6-phosphate dehydrogenase catalyzes the oxidation of glucose-6-phosphate, resulting in the production of 6-phosphoglucono-δ-lactone and NADPH. The reaction can be represented as:

{Glucose}_{6} - {phosphate}_{6} + NADP \to 6_{6} - phosphoglucono - δ lactone + NADPH

Explain the role of glucose-6-phosphate dehydrogenase: This enzyme is highly regulated and serves as the rate-limiting step of the pentose phosphate pathway. It ensures that glucose-6-phosphate is directed into the pathway when NADPH is needed.

Clarify why other enzymes are incorrect: Aldolase is involved in glycolysis, transketolase is involved in the non-oxidative phase of the pentose phosphate pathway, and phosphoglucomutase is involved in glycogen metabolism. None of these enzymes catalyze the first committed step of the pentose phosphate pathway.