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

2. Water

Biochemistry

2. Water

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Multiple Choice

At which pH does the enzyme pepsin become most active?

Around pH 7

Around pH 9

Around pH 12

Around pH 2

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Verified step by step guidance

Understand the context: Pepsin is a digestive enzyme that functions in the stomach, where the environment is highly acidic due to the presence of gastric acid (primarily hydrochloric acid). This provides a clue that pepsin is active at low pH values.

Recall the concept of enzyme activity and pH: Enzymes have an optimal pH at which they function most efficiently. For pepsin, this optimal pH is in the acidic range because it is adapted to the stomach's environment.

Analyze the options: The given pH values are 2, 7, 9, and 12. Among these, pH 2 is the most acidic, while pH 7 is neutral, and pH 9 and 12 are increasingly basic. Pepsin, being an enzyme in the stomach, is unlikely to function well at neutral or basic pH levels.

Correlate the enzyme's function with its environment: Since pepsin operates in the stomach, where the pH is maintained around 1.5 to 3 due to gastric acid, its activity is highest in this acidic range. This aligns with the given answer of pH 2.

Conclude: Based on the physiological environment of the stomach and the properties of pepsin, the enzyme is most active around pH 2, which is consistent with its role in protein digestion in acidic conditions.