Electrophoresis

HideShow resource information
  • Created by: Steff06
  • Created on: 13-05-16 14:39
Which electrode is negative and which is positive?
Anode is positive, cathode is negative.
1 of 13
What is the purpose of electrophoresis?
To separate DNA fragments based on their size.
2 of 13
What is required for electrophoresis? (5)
Buffer, power supply, DNA sample, electrophoresis tank, agarose gel.
3 of 13
Which fragments will run through the gel the quickest?
The shortest fragments will run through the gel the quickest.
4 of 13
Explain the method of electrophoresis in steps 1-3
1. Extract DNA. 2. Cut DNA into fragments using restriction endonucleases. 3. Place DNA samples into wells at negative end (cathode) of gel.
5 of 13
Steps 4-6
Immerse gel in tank of buffer solution, pass electric current through solution for usually 2 hours. 5. DNA negatively charged due to phosphate groups, will move towards anode from cathode. 6. Gel can be stained to see position of fragments.
6 of 13
Describe the method of Southern blotting
Nylon/nitrocellulose sheets placed over gel. Covered with paper towels, pressed and left overnight.
7 of 13
What is the issue with transferring the DNA to the sheets?
The fragments are not visible on the sheet.
8 of 13
What can be done to make the fragments visible?
Label DNA with radioactive/fluroescent marker before samples are run. Photographic film placed over sheet to show position of fragments. OR radioactive DNA probe used to look for specific gene (anneals to sequence in gene).
9 of 13
What is a DNA probe?
A short single-stranded piece of DNA which is complementary to section of DNA being investigated.
10 of 13
How can a probe be labelled?
Either by radioactive markers using 32p or with fluroescent markers which emit a colour in UV light.
11 of 13
What is annealing?
Probes binding by complementary base pairing to a fragment.
12 of 13
What are the uses of probes? (3)
Locate a specific gene for genetic engineering, identify same gene on different genomes of different species for gene comparison. Identify presence or absence of specific allele for a genetic disease.
13 of 13

Other cards in this set

Card 2

Front

What is the purpose of electrophoresis?

Back

To separate DNA fragments based on their size.

Card 3

Front

What is required for electrophoresis? (5)

Back

Preview of the front of card 3

Card 4

Front

Which fragments will run through the gel the quickest?

Back

Preview of the front of card 4

Card 5

Front

Explain the method of electrophoresis in steps 1-3

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all DNA, genetics and evolution resources »