Week 6: Recombinant DNA technology

Question 1

How do you cut DNA?

Answer 1

• use restriction endonucleases
• these enzymes are extracted from bacteria
• cuts a staggered cut

Question 2

How do you join DNA?

Answer 2

• use DNA ligase to reform phosphodiester bonds

Question 3

Describe a gene library.

Answer 3

• collection of recombinant clones
• use these to screen for clones containing genes of interest
• look for an expressed protein with an antibody

Question 4

What are the useful products from rDNA technology?

Answer 4

• insulin
• tissue plasminogen activator
• growth hormone
• vaccine proteins
• GM crops

Question 5

What are the uses of PCR?

Answer 5

• detection of pathogens
• genetic fingerprinting
• forensic analysis
• diagnosis of genetic disorders (prenatal)

Question 6

What are the limitations of PCR?

Answer 6

• sequence information is required to design 2 primers
• limit on length of amplified fragment
• significant mutation rate
• very sensitive to conditions
• tiny amounts of contaminating DNA will be amplified