Biotechnology Flashcards
U2L6
What is Biotechnology?
Biotechnology involves using living organisms (or their substances) to develop agricultural, medical or commercial products.
Our ability to directly modify genes is a new development.
What are restriction enzymes?
Restriction enzymes are basically scissors that cut double stranded DNA.
Each enzyme has a recognition site (its palindromic).
DNA cuts made by restriction enzymes either have overhangs (sticky ends) or blunt ends (right down the center).
Where do restriction enzymes come from?
Restriction enzymes originated from various species of bacteria.
They were designed by the bacteria to digest the DNA from bacteriophages that invaded them.
Humans isolated these enzymes and now we use them in biotech.
What is recombinant DNA?
Recombinant DNA is essentially DNA that’s created from two different sources (Recombinant = Recombined).
The DNA of both sources are cut using a restriction enzyme. They are annealed (or stuck together) by T4 DNA Ligase.
DNA strands will be able to anneal if they have complimentary sticky ends.
What is Gel Electrophoresis?
It is basically used after a restriction enzyme has done its work on a DNA strand. Restriction enzymes leave segments of DNA at different lengths.
Electrophoresis is used to separate these pieces, isolate them, and to determine their
length.
How does Gel electrophoresis work?
DNA is negatively charged and is repelled by an electric current.
During the operation, DNA strand are loaded into wells (Divots) on one side in an agarose gel (similar to Jell-O).
The DNA then travels through the thick agarose due to it being propelled by the electric current.
Smaller segments of DNA travel further while bigger ones are slower and tend to lag behind.
How does staining and fragment length determination work?
DNA strands are able to become visible by staining them with ethidium bromide which can be seen under a black light (UV).
The length of each DNA strand is determined by comparing its resting position to a DNA ladder.
A DNA ladder is a solution of fragments with a known length.
How is electrophoresis used in forensics?
Electrophoresis can be used to make comparisons between suspect DNA and crime scene DNA.
Because everyone has a different DNA sequence, everyone will have a different banding pattern observe in electrophoresis.
