gel electrophoresis

Question 1

describe DNA?

Answer 1

• DNA is the material from which chromosomes and genes are made
• it is found in the nucleus of all cells
• DNA is a polymer made from monomers called nucleotides

Question 2

what is a nucleotide in DNA?

Answer 2

a nucleotide is a molecule consisting of a phosphate group bonded to a deoxyribose sugar group. which is bonded to a base group
- DNA exists as two complementary strands. these base pairs form bonds with other base pairs

Question 3

what is gel electrophoresis?

Answer 3

is the use of an electrical current and agarose gel to separate DNA fragments based upon size and electrical charge.
- it is used to separate different lengths of DNA. this allows for DNA profilling

Question 4

what can DNA profiling be used for?

Answer 4

• forensic investigation
• checking parentage
• wildlife protection

Question 5

why does gel electrophoresis separate DNA based upon size?

Answer 5

all DNA molecules have the same amount of charge per mass because of this gel electrophoresis of DNA fragments separate them based on size only

Question 6

what is the process of gel electrophoresis?

Answer 6

1. prepare the gel
2. prepare the DNA - before the DNA is added, the gel must be placed in a chamber. one end of the box is hooked to a positive electrode and the other to a negative electrode.
   the main body of the box where the gel is placed, is filled with a buffer solution that can conduct electricity
3. separating the fragments - the shortest pieces of DNA will be close to the positive electrode
4. visualise the results

Question 7

how can you see the results of gel electrophoresis?

Answer 7

once the DNA has migrated far enough across the gel, the electric current is switched off
- to visualise the DNA, the gel is stained with a fluorescence dye that binds to the DNA, and is placed on a ultraviolet transilluminator which will show up the stained DNA as bright bonds

Question 8

what does the gel electrophoresis depend on?

Answer 8

• check the quality of the DNA

- check the quantity of the DNA

Question 9

what is a polymerase chain reaction

Answer 9

if you do not have enough DNA to carry out gel electrophoresis reaction you need to a polymerase chain reaction

Question 10

what is the process of a polymerase chain reaction?

Answer 10

1. heat the DNA sample, to separate the strands
2. cool sample and add primer
3. add nucleotides which join next to the primer and heat it
4. add the polymerase to catalyse the joining of nucleotides
5. repeat till enough DNA is produced