Enzyme Inhibition and Metabolic Control · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Read what inhibitors do to enzymes

Science · Organisms & Life Processes · ages 17-18
Name ______________________   Date ____________

  1. Where does a non-competitive inhibitor bind?

    • In the active site pocket
    • At a distant site away from the pocket
    • Directly onto the substrate

  2. What does a competitive inhibitor do to Vmax and Km?

    • Vmax stays put and Km rises
    • Vmax rises and Km stays put
    • Vmax falls and Km falls

  3. Raising substrate rescues the rate from a non-competitive inhibitor.

    Circle one:   True   False

  4. A rate curve drops its top but keeps the same halfway point. Which inhibitor?

    • Mixed
    • Non-competitive
    • Competitive

  5. A rate curve keeps its top but needs more substrate halfway. Which inhibitor?

    • No inhibitor at all
    • Non-competitive
    • Competitive

  6. Why does raising substrate rescue competitive inhibition but not non-competitive?

    • The same pocket can be crowded out; a distant twist cannot
    • Enzymes prefer crowded pockets
    • Substrate destroys all inhibitors on contact

  7. ATP builds up in a cell. What happens to early steps of sugar breakdown, and why?

    • They slow down, matching supply to demand
    • They stay fixed whatever the products do
    • They speed up to burn the surplus

  8. A student calls end-product inhibition enzyme damage. What is wrong?

    • End products never interact with enzymes
    • Nothing; inhibition is always damage
    • It is reversible control, lifting when product falls
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Read what inhibitors do to enzymes W1-mt_8VYolkJ_wR-s1

  1. At a distant site away from the pocket · It twists the whole enzyme instead of blocking the pocket.
  2. Vmax stays put and Km rises · The blocker fights for the pocket, so more substrate outcompetes it.
  3. False · No flood of substrate fixes a twisted machine.
  4. Non-competitive · A lowered top with the same halfway point is non-competitive.
  5. Competitive · Same top with a rightward shift signs competitive.
  6. The same pocket can be crowded out; a distant twist cannot · The binding place decides whether rescue is possible.
  7. They slow down, matching supply to demand · Energy-rich product brakes its own pathway; ADP reverses it.
  8. It is reversible control, lifting when product falls · The pathway senses its own products and answers them.
Worksheet · LightMySky