Answer: Increasing Km only.
- A Decreasing Vmax only
- B Increasing Km only
- C Decreasing both Km and Vmax
- D Increasing both Km and Vmax
Correct answer: B. Increasing Km only
Explanation: Competitive inhibitors compete with substrate for the active site. They increase apparent Km (lower affinity) but do not affect Vmax (can be overcome by excess substrate).
As substrate concentration rises, reaction rate increases steeply at first, then plateaus at Vmax once every enzyme molecule is working at full capacity; Km is the substrate concentration giving half-maximal rate, and a LOWER Km means the enzyme reaches that rate with less substrate (higher affinity).
Concept context
Carbohydrates, proteins, lipids, nucleic acids, and enzyme kinetics. Essential foundation for understanding metabolism.