Post-translational Modification and Protein Turnover · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.
En anglais

Edited after building

Science · Biochemistry & Molecular Biology · ages 18-19
Name ______________________   Date ____________

  1. What can a modification change about a protein?

    • Activity, location, partners or lifetime
    • Only the colour of the folded protein
    • Whether the cell keeps the protein at all

  2. Which is a post-translational modification?

    • Linking amino acids on the ribosome during building
    • Adding a phosphate group after the chain is built
    • Copying a DNA gene into messenger RNA

  3. Tagging an old or damaged chain with degradation-targeting polyubiquitin sends it to the proteasome for shredding. True or false?

    Circle one:   True   False

  4. The cell cycle moves from phase to phase on waves of new genes. True or false?

    Circle one:   True   False

  5. What does a short half-life say about a protein?

    • It is made from more messenger RNA each hour
    • It is tagged for destruction faster
    • It is folded more tightly than most

  6. Synthesis holds steady but destruction speeds up. What happens to the protein level?

    • It rises to a higher steady level
    • It stays exactly the same
    • It falls

  7. Two proteins with equal synthesis but different half lives must differ in translation speed. True or false?

    Circle one:   True   False

  8. A cell reacts in seconds with no new mRNA made. How?

    • Ribosomes translate a hundred times faster
    • Tags flip proteins already on site
    • Genes duplicate in seconds
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Answer key

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

Edited after building W1-mt_93cxQwxxkh-s1

  1. Activity, location, partners or lifetime · One tag can flip activity, move the protein, or shorten its life.
  2. Adding a phosphate group after the chain is built · Modifications are chemical changes made after the chain is built.
  3. True · Degradation-targeting polyubiquitin marks old or damaged chains for recycling.
  4. False · Waves of phosphorylation flip regulators without new messages.
  5. It is tagged for destruction faster · Fast tagging means quick recycling, whatever synthesis does.
  6. It falls · The bathtub drains faster than the tap fills it.
  7. False · Equal taps with different drains mean different tagging rates.
  8. Tags flip proteins already on site · Proteins already on site get activated, moved, or destroyed.
Worksheet · LightMySky