Electrophoresis

A process that is used to sort fragments of DNA by placing the digested DNA in a special gel and adding electricity.

PCR = Polymerase Chain Reaction = Making copies of DNA molecule Need 1. Primers – Small piece of DNA to start the reaction, 2. DNA Polymerase- Builds a new DNA molecule. Uses a bacteria called Thermus that lives in hot springs at 162 degrees F. 3. Nucleotides A, T, C, G Thermocycler Virtual Lab: University of Utah

Restriction Enzymes Special protein molecules that are able to cut the DNA at very precise locations These cut pieces of DNA can be used for: Electrophoresis - A process for studying gene patterns or similarities Recombination - Splicing a piece of DNA from one organism into another. First the DNA is cut into pieces using Restriction Enzyme Video

Restriction Enzymes were discovered in bacteria in the 1960s. In bacteria they act as their immune system destroying the viral DNA. When a virus called a bacteriophage infects a bacteria the Restriction Enzyme cuts up the viral DNA so it can’t hurt the cell. The enzyme looks for a specific sequence of nucleotides to attach to and then cuts the DNA at that location. It will cut a piece of DNA as many times as that sequence appears in the strand so many fragments are produced.

Restriction Enzyme DNA

DNA is cut into pieces by special chemicals called Restriction Enzymes

Restriction Fragment Length Polymorphism = RFLP Because the long DNA molecule will be cut a number of times at different locations the result is many different length pieces of DNA are produced these are RFLPs

For the process of Electrophoresis the pieces are loaded into the gel

The pieces of DNA move forming clumps of similar size pieces that look like dark bands DNA has a negative polarity so is repelled by the negative electrode.

Markers can be mixed with the DNA that show up under UV light to see how far the fragments have moved.

This is a negative image so the bands appear white Electrophoresis Video

Recombinant DNA – Bacteria Making Insulin