7.1 Gene Sequencing

Question 1

Genome

Answer 1

All of an organisms DNA

Question 2

PCR

Answer 2

Used to amplify DNA

Question 3

Reaction mixture in PCR

Answer 3

DNA sample
Primers- short stretches of DNA that target unique sequences
Free nucleotides
Heat stable DNA polymerase

Question 4

PCR (Denaturation)

Answer 4

Reaction mixture is heated to 95 degrees
This breaks the hydrogen bonds between complementary bases
Separates the 2 strands

Question 5

PCR (Annealing)

Answer 5

Mixture is cooled to 55 degrees
Primers can bind to strands

Question 6

PCR (Extension)

Answer 6

Temperature is increased to 70 degrees
DNA polymerase creates a copy of the sample using the free nucleotides

Question 7

DNA Sequencing

Answer 7

Used to predict the amino acid sequence of proteins

Question 8

DNA mixture in DNA sequencing

Answer 8

Bases A,G,C and T
DNA polymerase
Primers
Fluorescently labelled terminator bases

Question 9

DNA sequencing steps

Answer 9

1) DNA mixture is divided into 4 separate sequencing reactions
2) Gel Electrophoresis is used to separate fragments by size
3) Fragments can be visualised under UV light
enabling base sequence to be read

Question 10

Southern Blotting

Answer 10

Alkaline buffer added
Dry absorbent material draws solution containing DNA fragments
Fragments visible as blots
Gene probes bind with DNA

Question 11

DNA profiling steps

Answer 11

1) Satellites of DNA are cut with restriction endonuclease enzymes
2) DNA is separated + visualised using gel electrophoresis
3) Southern blotting occurs
4) Blots are compared + number of satellites visualised as a graph
5) The more similar the repeats are, the more closely related the 2 people are