Molecular Techniques Flashcards
What produce endonucleases
Bacteria
What do restriction enzymes do
Recognise and degrade foreign DNA
Which electrode do DNA fragments travel toward in electrophoresis and why
Positive as DNA is negatively charged
What sized fragments travel the furthest
Small
What does DNA gel electrophoresis do
Separate fragment based on size
How are genes cloned
Isolate specific gene with restriction enzymes and insert into plasmid vector to place into bacteria to replicate naturally
What are plasmids
Small circular DNA
Give an example of when human genes are cloned
To make human insulin
What enzyme concerts mRNA into cDNA
Reverse transcriptase
What disease is currently being treated using gene therapy
Cystic fibrosis
What enzyme is used in PCR and why
Taq Polymerase as it can work at higher temperatures
What is the first step in PCR
Heat strands to 95 degrees to denature DNA to give single strands
What is the second step of PCR
Cool DNA to 55 degrees to allow DNA primers to bind
What is the final step of PCR
Heat to 72 degrees to allows taq Polymerase to bind and add nucleotides from the 3’ end.
Why is PCR used
Look for mutations, to see if there’s a loss or gain of restriction fragments or to see size of product
Why can you use PCR to determine if someone has sickle cell anaemia
In sickle cell the mutation changes a restriction site and so this site will not be cut like it would in normal DNA
What does PCR result in
Lots of copies of a specific piece of DNA
What is protein gel electrophoresis
Separation of proteins
What different types of protein electrophoresis are there?
SDS page, isoelectric focussing and 2D page