Getting DNA into Cells and Finding the Right Clones
Transformation and selection
Transformation
Transformation is the process of getting a plasmid into a host cell, often a bacterium. Not every cell takes up the plasmid, so scientists need ways to find the cells that did.
Selection markers
Many plasmids carry a selection marker, such as antibiotic resistance. If the cells grow on the right medium, only cells with the plasmid survive.
Important safety note
In real laboratories, antibiotic use and cell handling must follow strict safety and training rules.
Screening
Selection tells scientists which cells have a plasmid, but screening helps them find the ones with the correct inserted gene.
Selection vs screening
| Process | What it tells you |
|---|---|
| Selection | Which cells likely contain a plasmid |
| Screening | Which plasmid has the correct DNA insert |
What is transformation in genetic cloning?
Transformation is the introduction of DNA into cells.
Correct answer: Getting plasmid DNA into a host cell
Why do scientists use selection markers?
Only cells with the marker can survive under the selection conditions.
Correct answer: They help identify cells that have taken up the plasmid.
Why is screening needed after selection?
Some cells may contain plasmids but not the correct insert.
Correct answer: To find cells with the correct DNA insert
What is one example of a selection marker?
Antibiotic resistance is commonly used to identify cells carrying the plasmid.
Correct answer: Antibiotic resistance