Flashcards in Visualising DNA Deck (9)
What does gel electrophoresis do?
Separates DNA fragments of different sizes
Needs a chemical dye to see the DNA;
Usually ethidium bromide or SYBR green or gold
How does gel electrophoresis work?
DNA moves through the gel at a rate that is inversely proportional to the chain length of the DNA
How do you get a higher resolution on gel electrophoresis?
Using radioactive labelled DNA run on a polyacrylamide gel followed by autoradiography
What is pulsed-field gel electrophoresis?
Separation of large DNA molecules by periodically changing the electric field from a gel matrix
Alternating voltage improves the resolution of larger molecules
The voltage is switched between 3 directions;
The central axis of the gel and 60 degrees on each side of the central axis
The electric field alternates 120 degrees every 90 seconds for 18-24 hours at 14 degrees Celcius
Thus the DNA doesn't move in a straight line but in a net forward migration pattern
Name 3 ways DNA can be denatured?
Heat- DNA with higher GC content denatures at a higher temperature
What is hybridisation?
The process by which separated DNA/RNA will reform a double helix
What are the conditions favouring base pairing in hybridisation?
Removal of denaturants
What is Southern blotting?
A way of analysing mRNA