gel electrophoresis

Question 1

what is the aim of gel electrophoresis?

Answer 1

separate DNA strands based on their lengths into bands

Question 2

what are wells?

Answer 2

depressions in the gel where DNA is placed

Question 3

what are DNA ladders?

Answer 3

• run at the same time as other samples
• contain segments of DNA = lengths
• results of the unknown sample are compared to the ladder to determine the length of DNA strands in the sample

Question 4

how can DNA be visualized in the gel?

Answer 4

ethidium bromide added to agar > DNA moves + picks up chemical > ulterviolet light > DNA is fluorescent

methylene blue (a dye that binds to DNA) > areas of DNA stain deep blue = visible to naked eye

Question 5

what is the first step of gel electrophoresis?

Answer 5

isolate the gene and use a restriction enzyme to cut out the gene of interest
create recombinant DNA

Question 6

what is the second step of gel electrophoresis?

Answer 6

use the PCR process to make more DNA fragments

Question 7

what is the third step of gel electrophoresis?

Answer 7

place DNA fragments in the wells with a dye and a known sample

Question 8

what is the fourth step of gel electrophoresis?

Answer 8

electrical current is passed through the gel

negatively charged DNA fragments move towards the positively charged cathode

Question 9

what is the fifth step of gel electrophoresis?

Answer 9

smaller DNA fragments move faster and further than larger DNA segments

Question 10

what is the sixth step of gel electrophoresis?

Answer 10

results in different lengths of bands which results in a DNA profile