Explain Resistance Gene Spread
Use culture and antibiotic evidence to explain resistance gene spread.
- Aseptic culture technique: Culture results need uncontaminated samples.
- Antibiotic selection pressure: Drug exposure can favor resistant bacteria.
Prerequisites are inferred: pending teacher review.
Re-learn the skill with worked practice and clear examples.
Explain how a resistance gene spreads between bacteria by plasmid transfer (conjugation).
Using the diagram, how does the recipient bacterium become resistant WITHOUT reproducing?
Reviewed- A.It receives a copy of the resistance plasmid from the donor through a pilus
- B.It mutates its own chromosome by chance during the photo
- C.It is born already resistant from a resistant parent
- D.It absorbs the antibiotic and stores it for later
Show the worked solution ▾
Answer: A. It receives a copy of the resistance plasmid from the donor through a pilus
- Step 1: Read the figure: A copy of the R plasmid passes across the pilus.
- Step 2: Name the process: Gene moves between living cells = horizontal transfer.
Why it's right: In conjugation, the donor passes a copy of its resistance plasmid to the recipient through a pilus, so the recipient gains resistance without reproducing.
- B: The recipient gains the gene by transfer, not a new chance mutation.
- C: Inheriting from a parent is vertical transfer; the diagram shows transfer between two existing cells.
- D: The cell gains a gene, not stored antibiotic.
Aligned to Culturing · reading level ~grade 9
- In Unit 1.2 Culturing & Resistance, this skill turns class evidence into a result another person can check.
Fill these in as you work through the lesson.
- Plasmid (a small ____ of DNA that can carry a resistance gene):
- Conjugation (two bacteria connect by a pilus and pass a ____ of the plasmid):
- Horizontal gene transfer (a gene moves ____ living cells instead of parent to offspring):
- Vertical inheritance (a gene passes from ____ to offspring):
In horizontal gene transfer, a resistant cell passes a to another living cell, so resistance can spread without the bacteria .
- What is a plasmid, and what can it carry?
- How does conjugation move a resistance gene between two cells?
- Why does horizontal transfer spread resistance faster than inheritance alone?
A resistant E. coli cell sits next to a non-resistant Salmonella cell. Explain how the Salmonella could become resistant without reproducing, and name the process.