Small RNAs and Silencing After Transcription · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Silenced after the message is made

Science · Genetics & Evolution · ages 20-21
Name ______________________   Date ____________

  1. Where does small RNA silencing act?

    • Before transcription starts
    • Inside the DNA helix
    • On messages already made

  2. What picks which transcripts a small RNA silences?

    • Base pairing between guide and target
    • The length of the cell
    • The number of ribosomes

  3. A near perfect guide match slices its target message and lowers message levels.

    Circle one:   True   False

  4. A perfect match guide is added to a cell. Which readout moves first?

    • Protein only, messages stay flat
    • Message levels fall as targets are sliced
    • Nothing moves at all

  5. Messages measure normal but protein has crashed. What best explains it?

    • A partial match blocked translation
    • The promoter broke
    • Slicing destroyed every message

  6. What does an mRNA only assay miss in a translationally blocked cell?

    • Nothing, it catches everything
    • Only the promoter state
    • The entire silencing, since messages look unchanged

  7. Promoter control and small RNA control act at the same step of gene expression.

    Circle one:   True   False

  8. A student says normal message levels prove a gene is fully active. What is the error?

    • Translation can still be blocked while messages look fine
    • Message levels never matter
    • Promoters override translation
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Answer key

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

Silenced after the message is made W1-mt_1AozDyS1Mn-s1

  1. On messages already made · It tunes which existing transcripts get used, not which genes fire.
  2. Base pairing between guide and target · The seed match selects exactly the transcripts that get hit.
  3. True · Full pairing triggers destruction, so sequencing sees the drop.
  4. Message levels fall as targets are sliced · Near perfect pairing destroys the message.
  5. A partial match blocked translation · Blocking leaves messages intact while protein falls.
  6. The entire silencing, since messages look unchanged · Messages stay present while protein drops, so the assay reports normal.
  7. False · Promoters pick which genes fire, small RNAs pick which messages get used.
  8. Translation can still be blocked while messages look fine · A transcribed gene can still make almost no protein.
Worksheet · LightMySky