Molecular biology lab

IIn this laboratory you will use some basic tools of molecular biology to gain an understanding of some of the principles and techniques of genetic engineering. In the first part of the lab, you will use antibiotic-resistance plasmids to transform Escherichia coli. In the second part, you will use gel electrophoresis to separate fragments of DNA for further analysis.

Genetic transformation occurs when a host organism takes in foreign DNA and expresses the foreign gene. In this part of the lab, we will introduce a gene for resistance to the antibiotic ampicillin into a bacterial strain that is killed by ampicillin. If the susceptible bacteria incorporate the foreign DNA, they will become ampicillin resistant. In the 1960s, scientists discovered that bacteria have enzymes that cut, or "digest," the DNA of foreign organisms and thereby protect the cells from invaders such as viruses. Scientists have now isolated several hundred of these enzymes, known as restriction enzymes, or restriction endonucleases. Each is able to recognize and cut at a specific DNA sequence, known as a recognition sequence.

we also will use gel electrophoresis to separate samples of DNA that have been digested by restriction enzymes. Then you will compare fragments of unknown size to fragments of a known size to calculate the unknown fragment sizes.