21.3 in vitro gene cloning

Question 1

what are the stages of PCR?

Answer 1

1. DNA heated to 90 to 95°C;
2. strands separate;
3. cooled / to below 70°C
4. primers bind;
5. nucleotides attach;
6. by complementary base pairing;
7. temperature 70 - 75°C;
8. DNA polymerase joins nucleotides together;
9. cycle repeated;

Question 2

what are primers?

Answer 2

short sequences of DNA/ RNA that are complementary to one end of the 2 DNA fragments

Question 3

why are primers used?

Answer 3

provide the starting sequence for DNA polymerase to begin DNA copying

Question 4

what are the advantages of in vitro (PCR) gene cloning?

Answer 4

• it is extremely rapid

- doesn’t require living cells

Question 5

what are the advantages of in vivo (using vectors) gene cloning?

Answer 5

• useful when we wish to introduce a gene into another organism
• involves no risk of contamination
• very accurate
• cuts out specific genes
• produces transformed bacteria that can be used to produce large quantities of gene products