DNA fingerprinting

Question 1

Role of DNA fingerprinting

Answer 1

Methods used to identify an individual from a sample of DNA by looking at unique pattern in DNA

Method which relies on the unique pattern made by a series of DNA fragment after separating them according to their length by gel electrophoresis

Question 2

History

Answer 2

1984 by Sir Jeffery which he realised he could detect variations in human DNA

Question 3

Comparison

Answer 3

PCR in terms of forensic application criminals etc

A piece of x-ray filmed exposed to fragments ,r adioactive probe had become attached .

Pattern would be analysed - Lead to investigation

Question 4

Procedure - Ecstacy

Answer 4

Extraction of DNA:

From cell /tissue of muscle , semen , saliva or blood
Blood is being treated with a series of chemicals until pure DNA emerges as a white solid

DNA stored , dissolved in water and fridge .

Question 5

Cutting up the DNA using an enzyme

Answer 5

Involves using restriction enzyme
Using colourless liquid to the DNA with another colourless liquid
Enzyme take quite some to cut all places in the strands

Question 6

Separating DNA fragments on the gel

Answer 6

Separates the different sizes of the DNA fragment generated by cutting up the DNA.

Observe the small fragments move faster than larger ones , so DNA fragments are separated as they move in the gel .

Question 7

Transferring DNA on paper

Answer 7

gel separated onto white nitrocellulose paper , so paper carries an extract replica of DNA on the gel .

Question 8

Adding the radioactive probe

Answer 8

Probe sticks to the fragments of the DNA that has matching sequence , but only those fragments that have matching sequence of letters , no other fragments

Question 9

Setting up X- ray film

Answer 9

Dark mode , nitrocellulose paper placed against a piece of x-ray film

X- ray film records pattern of radioactivity on the paper , probe has struck .

Pattern of DNA fragment see where probes stuck