Three ways to borrow genes

Science · Microbiology · ages 20-21

Name ______________________ Date ____________

Which route needs living donor contact through a pilus?
- Transformation
- Conjugation
- Transduction
Which route uses a virus as the delivery vehicle?
- Transformation
- Conjugation
- Transduction
Only transformation requires the recipient to take up naked DNA from the surroundings.
Circle one: True False
Enzymes destroy all free DNA, yet the gene still spreads. What follows?
- Transformation is ruled out
- Transduction is ruled out
- Conjugation is ruled out
A filter blocks cells but passes fluid, yet the gene still spreads. What follows?
- Conjugation must be the route
- Conjugation is ruled out
- All transfer has stopped
A gene tree disagrees with the cell tree. What best explains it?
- The gene crossed species lines by transfer
- All mutations stopped
- The cells never divided
Transformation, transduction, and conjugation all need a pilus bridge between living cells.
Circle one: True False
A student draws the cell family tree from one resistance gene. What is the error?
- Genes never transfer
- That gene may have traveled while the cells stayed put
- Trees cannot use genes

Answer key

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

Conjugation · A bridge passes a plasmid copy cell to cell.
Transduction · A phage packs host DNA by mistake and injects it onward.
True · Competence matters there and in neither other route.
Transformation is ruled out · Uptake needs free DNA, so its absence kills that route.
Conjugation is ruled out · Contact transfer cannot cross a cell blocking wall.
The gene crossed species lines by transfer · Borrowed genes carry their own travel history.
False · Only conjugation needs living contact; others use surroundings or virus.
That gene may have traveled while the cells stayed put · One traveler cannot vouch for the whole household.