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

Which of the following statements is true with respect to enzyme activity?

Enzyme activity is independent of substrate concentration.

All enzymes require a metal ion as a cofactor to function.

Enzyme activity can be affected by changes in temperature and pH.

Enzymes are consumed during the reactions they catalyze.

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Verified step by step guidance

Step 1: Begin by understanding the role of enzymes in biochemical reactions. Enzymes are biological catalysts that speed up reactions without being consumed in the process. This means they are not used up during the reaction, which makes the statement 'Enzymes are consumed during the reactions they catalyze' incorrect.

Step 2: Evaluate the statement 'Enzyme activity is independent of substrate concentration.' Enzyme activity is actually dependent on substrate concentration, as described by the Michaelis-Menten kinetics. At low substrate concentrations, enzyme activity increases with substrate concentration until it reaches saturation. Therefore, this statement is also incorrect.

Step 3: Analyze the statement 'All enzymes require a metal ion as a cofactor to function.' While some enzymes do require metal ions (e.g., zinc, magnesium) as cofactors, not all enzymes need them. Many enzymes function without metal ions, using other types of cofactors or none at all. Thus, this statement is incorrect.

Step 4: Consider the statement 'Enzyme activity can be affected by changes in temperature and pH.' Enzymes are highly sensitive to environmental conditions. Changes in temperature and pH can alter the enzyme's structure (denaturation) or affect the active site, impacting its activity. This statement is correct.

Step 5: Conclude that the correct answer is the statement 'Enzyme activity can be affected by changes in temperature and pH,' as it accurately reflects the nature of enzyme function and sensitivity to environmental factors.