Manipulating Genomes

Question 1

PCR

Answer 1

1. DENATURATION
   - 95°C
   - DNA fragments mixed with DNA nucleotides and primers
   - this temp breaks the H bonds between complementary base pairs
   - The DNA strands separate
2. ANNEALING
   - 55°C
   - primers bind to complementary bases
   - required for replication of the DNA strands
3. ELONGATION
   - 72°C
   - DNA polymerase adds bases to the primer, building up complementary strands of DNA and so producing double stranded DNA identical to the original sequence

Question 2

Gel Electrophoresis

Answer 2

1. DNA is amplified using PCR
2. DNA is cut into smaller fragments using restriction enzymes
3. DNA fragments are placed into the wells at the end of the agarose plate near the cathode ( negative)
4. The plate is immersed in a buffer solution which helps maintain the pH
5. An electrical current is passed through the plate and DNA starts to separate as the negative phosphate group of DNA is attracted to the positive anode
6. The shorter DNA fragments move further than the longer fragments
7. Ethidium bromide is used as a stain to see the fragments