Transformation notes
Wed, Apr 28, 2027 · Week 15 · Biotechnology for Health (Biomedical Innovations)
Today's goal: Explain bacterial transformation and how antibiotic selection identifies successful clones.
What a finished product looks like
This is a model of the work you should turn in today. Use it to check your own: match the structure and the level of detail, do not copy it. Your data and wording should be your own.
Definitions: Transformation is when bacteria take up free plasmid DNA from their surroundings. Competent cells are bacteria whose membranes have been weakened (usually with a calcium solution) so DNA can enter.
Heat-shock steps: Mix competent cells with plasmid on ice, then place at 42 degrees C for about 45 to 50 seconds. The brief heat opens pores so the plasmid enters, and returning to ice keeps the cells from dying.
How antibiotic selection works: The plasmid carries an antibiotic-resistance gene. On antibiotic agar, only cells that took up the plasmid can survive; cells without it die, so every colony you see is a successful transformant.
Predicted plate results:
- Cells + plasmid on antibiotic agar: colonies grow (transformed cells survive).
- Cells + plasmid on plain agar (no antibiotic): a lawn of growth (everything grows; this checks the cells are alive).
- Cells, no plasmid, on antibiotic agar: no growth (nothing is resistant).
- Cells, no plasmid, on plain agar: a lawn of growth (cells are healthy).
| Plate | Cells | Plasmid | Antibiotic | Predicted result |
|---|---|---|---|---|
| 1 | Yes | Yes | Yes | Colonies |
| 2 | Yes | Yes | No | Lawn of growth |
| 3 | Yes | No | Yes | No growth |
| 4 | Yes | No | No | Lawn of growth |
Also due today: Submit your transformation notes and predictions in the course LMS today.
WebXam problem for today's skill
One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.
Tap an answer to see the full explanation. Nothing is recorded or graded.