Controlling Growth: What Sterile Means and How It Is Achieved · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

From slowing microbes to sterile

Science · Microbiology · ages 18-20
Name ______________________   Date ____________

  1. Which mechanism belongs to moist heat?

    • Shattering genomes
    • Trapping cells in pores
    • Denaturing proteins and membranes

  2. Which choice describes a sterile item?

    • Almost no microbes remain
    • No living microbes at all
    • Only harmless microbes remain

  3. Endospores die more easily than ordinary growing cells.

    Circle one:   True   False

  4. After treatment ends, microbes grow again. What did the agent do?

    • It killed them slowly
    • It sterilised the item
    • It only inhibited them

  5. A vitamin solution is ruined by heat. How do you sterilise it?

    • Boil it longer
    • Filter it through tiny pores
    • Leave it in sunlight

  6. A chemical wipe fails on a dirty bench but works on a clean one. Why?

    • Dirt load changes whether it kills or pauses
    • The bench eats the chemical
    • Microbes learn to hide

  7. Why is there no universal best control method?

    • Scientists disagree on purpose
    • Sterile means different things
    • Each pairs one mechanism with what the item tolerates

  8. Which choice states a complete method decision?

    • Autoclave it and hope
    • Filter the heat sensitive serum to trap its bacteria
    • Heat everything just in case
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Answer key

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

From slowing microbes to sterile W1-mt_j1kqpjUMzk-s1

  1. Denaturing proteins and membranes · Autoclave heat denatures proteins and membranes.
  2. No living microbes at all · Sterile means zero living microbes, including the toughest forms.
  3. False · Endospores survive boiling and drying that kill ordinary cells.
  4. It only inhibited them · Regrowth after removal proves inhibition, not killing.
  5. Filter it through tiny pores · Filtration traps cells physically without heat damage.
  6. Dirt load changes whether it kills or pauses · Dose, contact time, and dirt load decide kill versus pause.
  7. Each pairs one mechanism with what the item tolerates · Only the right match of mechanism, material, and microbe works.
  8. Filter the heat sensitive serum to trap its bacteria · It names the material, the target, and why the mechanism fits.
Worksheet · LightMySky