Answer: The final product inhibits an early enzyme in its own synthesis.
- A The first enzyme in the sequence directly activates the formation of the final product
- B The final product inhibits an early enzyme in its own synthesis
- C Excess substrate itself binds and inhibits the enzyme that processes it
- D Reaction products universally enhance the activity of the enzymes that made them
Correct answer: B. The final product inhibits an early enzyme in its own synthesis
Explanation: End-product (feedback) inhibition: the final product of a pathway inhibits an early enzyme (often the first committed step). This is a key mechanism for controlling metabolic flux. Example: isoleucine inhibits threonine deaminase.
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.