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

7. Enzyme Inhibition and Regulation

Enzyme Inhibition

Biochemistry

7. Enzyme Inhibition and Regulation

Enzyme Inhibition

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Multiple Choice

The synthesis of a repressible enzyme is stopped by the:

presence of a competitive inhibitor

binding of an allosteric activator

accumulation of the end product

absence of the substrate

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Verified step by step guidance

Understand the concept of a repressible enzyme: A repressible enzyme is part of a biochemical pathway where its synthesis is regulated by feedback inhibition. This means the production of the enzyme is controlled by the concentration of the end product of the pathway.

Learn about feedback inhibition: Feedback inhibition occurs when the end product of a metabolic pathway accumulates and binds to a regulatory site on an enzyme or a repressor protein, effectively stopping further synthesis of the enzyme or pathway activity.

Analyze the options provided: Evaluate each option in the context of repressible enzyme regulation. For example, the presence of a competitive inhibitor affects enzyme activity but does not directly stop enzyme synthesis. Similarly, the binding of an allosteric activator typically enhances enzyme activity rather than stopping synthesis.

Focus on the correct mechanism: The accumulation of the end product is the key factor that halts the synthesis of a repressible enzyme. This is because the end product acts as a signal to the cell that enough of the product has been made, triggering feedback inhibition.

Conclude the reasoning: The absence of the substrate does not directly stop the synthesis of the enzyme; it only affects the enzyme's ability to catalyze reactions. Therefore, the correct answer is the accumulation of the end product, as it directly regulates enzyme synthesis through feedback inhibition.