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

6. Enzymes and Enzyme Kinetics

Enzymes

Biochemistry

6. Enzymes and Enzyme Kinetics

Enzymes

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Multiple Choice

Pepsin is an enzyme found in the stomach that functions best at an acidic pH. Why does pepsin exhibit optimal activity under these conditions?

Pepsin requires alkaline conditions to hydrolyze peptide bonds.

The acidic pH maintains the correct conformation of pepsin's active site, allowing efficient substrate binding and catalysis.

The acidic pH increases the concentration of substrate in the stomach.

The acidic pH denatures pepsin, making it more reactive.

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Verified step by step guidance

Understand the role of pepsin: Pepsin is a proteolytic enzyme that catalyzes the hydrolysis of peptide bonds in proteins, breaking them down into smaller peptides. It is secreted in the stomach as an inactive precursor, pepsinogen, which is activated in acidic conditions.

Recognize the importance of pH for enzyme activity: Enzymes have an optimal pH range where their structure and function are most effective. For pepsin, this optimal pH is highly acidic, typically around pH 1.5 to 2.0, which matches the environment of the stomach.

Explain the relationship between pH and enzyme conformation: The acidic pH helps maintain the correct three-dimensional structure of pepsin's active site. This conformation is crucial for substrate binding and catalysis, as the active site must be properly shaped to interact with peptide bonds in proteins.

Clarify why alkaline conditions are not suitable: Alkaline conditions would disrupt the ionic and hydrogen bonding interactions that stabilize pepsin's active site. This would lead to a loss of enzymatic activity, as the active site would no longer be functional.

Address misconceptions: The acidic pH does not denature pepsin or increase substrate concentration directly. Instead, it ensures the enzyme remains in its active form and facilitates efficient catalysis by maintaining the active site's structure.