Final answer:
To determine the percentage of competent E. coli cells that have been transformed, one compares the number of colonies that grow on an antibiotic-containing plate to the total number of cells that were originally plated. This provides the transformation efficiency, indicative of the competency of the cells and the success of the transformation process.
Step-by-step explanation:
Transformation Efficiency of Competent E. coli Cells
In a biological context, specifically in the field of molecular biology, the transformation of competent E. coli cells is a process where these cells are enabled to take up foreign DNA. During the process, competent cells are prepared using a cold solution of calcium chloride, which makes their cell walls more permeable to DNA. Once these cells take up the DNA, they can express the new genetic material, such as an antibiotic resistance gene. However, not all cells undergo transformation successfully. To measure the percentage of cells that have been transformed, one would count the number of colonies on a selective media plate that contains an antibiotic, like ampicillin, and compare that to the total number of cells originally plated. The transformation efficiency can thus provide significant insights into the competency of the bacterial culture and the success of the transformation process.
For instance, if the cells were mixed with a plasmid containing a gene for ampicillin resistance and then plated onto the agar containing ampicillin, only the cells that have successfully taken up and expressed the plasmid will survive and grow into colonies. By comparing the number of such colonies to the total amount of E. coli cells plated, one can calculate the percentage of competent cells that were transformed.