Question

You have a tube of pGLO plasmid at a concentration of 15 ng/uL and you perform transformation experiments using protocol below. The protocols use E. coli that are made competent (i.e. – able to take up exogenous DNA).  

Protocol is outlined below:

1. 1 uL of pGLO was added to 100 uL of competent cells in transformation buffer (these cells had been made competent by a different procedure than the one we used in class but we don’t need to concern ourselves with the details here).
2. The mixture was incubated on ice and heat shocked as described in Exercise 16.
3. After heat shock, 0.9 of LB was added and the cells were incubated at 37⁰ for 30 min.
4. 1 uL of the transformed cells was then added to 100 uL LB and entire diluted mixture was spread onto LB-amp-ara plates. (This dilution is necessary because 1 uL would soak into the plate before you can spread it out and all of your CFU would end up in a tiny area of the plate).

After following the Transformation procedure, you count 235 CFU that glow when the plate is illuminated with UV light.

1. What is the transformation efficiency (CFU/ug plasmid) obtained from Protocol B? Show your work.

Answer 1