Visualising DNA Flashcards Preview

BIO2030 Biotechnology > Visualising DNA > Flashcards

Flashcards in Visualising DNA Deck (9)
Loading flashcards...

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
Extreme pH
Conc. urea


What is hybridisation?

The process by which separated DNA/RNA will reform a double helix


What are the conditions favouring base pairing in hybridisation?

Low temperature
Higher [salt]
Removal of denaturants


What is Southern blotting?

A way of analysing mRNA


Describe Southern blotting's mechanism

RNA is separated by agarose gel electrophoresis
RNA is blotted onto nylon or nitrocellulose membrane
Incubate membrane with labelled probe
Locate hybridising bands by autoradiography