Genome Projects + Technologies

Question 1

What is DNA cloning?

Answer 1

Making many copied of a DNA molecule

Question 2

What are the reasons for DNA cloning?

Answer 2

1. Have many copies to find its base sequence e.g. for forensic analysis
2. Create lots of copies of a DNA molecule you want to use to make particular proteins

Question 3

In vitro cloning

Answer 3

In lab (primarily used for to find base sequences)

Question 4

In vivo cloning

Answer 4

In living cells (primarily used for making particular proteins)

Question 5

PCR (Polymerase Chain Reaction) - In vitro cloning

Answer 5

Automated method to copy lengths of DNA
1. Separation of DNA strands - add DNA, taq polymerase, primers, DNA nucleotides to the thermocycler and increase temp to 95 degrees Celsius
- hydrogen bonds break separating the 2 strands
2. Annealing of primers - cool to 55 degrees Celsius, allows primers to bind to complementary bases at end of target DNA sequence
- this allows Taq polymerase to bind and start copying DNA fragment
- also prevents 2 separate strands rejoining
- primers direct Taq to where it should start synthesising
3. Synthesis of DNA - increase temp to 72 degrees Celsius (optimum temp for taq polymerase to synthesise DNA by adding complementary nucleotides along separated strand)
4. Repeat cycle to generate as many copies as required

Question 6

Advantages of PCR

Answer 6

• Rapid whereas in vivo could take days to obtain same quantity
• living cells not required therefore no complex culturing required
• can start with 1 DNA molecule (small quantities)

Question 7

Limitations of PCR

Answer 7

• DNA produced wont produce any transcripts or proteins by themselves outside of a living cell
• to produce a product e.g. insulin - transformation needs to occur