Chapter 2.5 - Sanger Sequencing And The Polymerase Chain Reaction Flashcards
What are four types of gene technologies
The polymerase chain reaction
Cutting out DNA fragments using restrictive enzymes
Gel electrophoresis
Finding specific sequences of DNA and using DNA probes
What is a genome
A genome is the entire DNA sequence of an organism.
What can gene technologies help us with
Genetic engineering
Gene cloning
Gene therapy
What is the polymerase chain reaction?
The PCR can be used to make millions of copies of a fragment of DNA in jut a few hours
The fragment could contain a gene or just a bit of DNA that you’re interested in. PCR is repeated over and over I make lots of copies
Outline the first step of the polymerase chain reaction
A reaction mixture is set up that contains the DNA sample, free nucleotides, primers and DNA polymerase.
What are primers
Primers are short pieces of DNA that are complementary to the bases at the start of the fragment you want. (Prim=primary=first)
What is DNA polymerase
DNA polymerase is an enzyme that creates new DNA strands
Outline the second step of the polymerase chain reaction
The DNA mixture is heated to 95•C to break the hydrogen bonds between the two strands of DNA. The mixture is then cooled to 50-65•C so that the primers can bind to the strands
Outline the third step of the polymerase chain reaction
Te reaction mixture is heated to 72•C, so DNA polymerase can work.
The DNA polymerase lines up free DNA nucleotides alongside each template strand.
Complementary base pairing means new complementary strands are formed.
Why is the PCR heated to 72 degrees?
To allow the DNA polymerase to work by lining up free DNA nucleotides alongside each template strand complementary.
What is the fourth step of the PCR
Two new copies of the fragment of DNA are formed and one cycle of PCR is complete.
When the cycle starts again- the mixture is heated to 95•C and this time all four strands (2 original 2 new) are used as templates.
What do restrictive enzymes do in gene technology
They isolate (cut out) a DNA fragment from an organisms DNA
