Operon Logic: Induction, Repression and Feedback on Transcription · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

One switch for a whole team

Science · Microbiology · ages 19-21
Name ______________________   Date ____________

  1. Milk sugar appears. How does its digesting switch turn on?

    • The sugar pulls the blocker off
    • The sugar destroys the genes
    • The sugar feeds the blocker

  2. What does a grouped bacterial switch look like?

    • One gene with no switch
    • Related genes under one shared control
    • Genes scattered with no control

  3. Building blocks pile up. What does the control do?

    • It turns building on
    • It does nothing
    • It clamps the switch shut

  4. The blocker protein breaks and cannot grip. What is the result?

    • Stuck on, running nonstop
    • Stuck off forever
    • Deleted from the cell

  5. Breakdown switches rest off while building switches rest on.

    Circle one:   True   False

  6. The grip site breaks so nothing can hold it. What is the result?

    • Stuck off
    • Stuck on
    • Cut in half

  7. A friend says blocker proteins switch genes on. Is that right?

    • No, blockers stop the machine; only their removal starts it
    • Yes, blockers fire the machine up
    • Yes, grip sites copy genes

  8. No milk sugar is around. What does the digesting switch do?

    • It runs at full speed
    • It slows a little
    • It stays silent
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Answer key

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

One switch for a whole team W1-mt_yNvJjGMSJQ-s1

  1. The sugar pulls the blocker off · With the blocker gone the copying machine passes and digesting enzymes appear.
  2. Related genes under one shared control · Related enzymes share one starter plus a nearby site where a blocker decides.
  3. It clamps the switch shut · Piled up product activates the blocker, which shuts down further building.
  4. Stuck on, running nonstop · A blocker that cannot grip never stops the machine, so output runs constant.
  5. True · Breakdown pays only when its target is around, while building runs by default.
  6. Stuck on · A site nothing can grip is the same as no brake at all.
  7. No, blockers stop the machine; only their removal starts it · Control sits at the cheapest point: no message is made until enzymes are needed.
  8. It stays silent · The blocker sits on by default and only its target pries it off.
Worksheet · LightMySky