DNA Tech

Question 1

Describe genetic fingerprinting:

Answer 1

ED SSHED:
-extraction of DNA via a swab in cheek
-digestion via restriction endonuclease
-separation via gel electrophoresis then transferred to nylon membrane
-hybridisation with DNA probes (radioactive)
-Development of membrane with x ray film, dark bands where probes attach

Question 2

How does a restriction endonuclease work?

Answer 2

-finds the recognition site (usually palindromic)
-cuts at a cleavage site
-leaves either sticky or blunt ends
-sticky ends are complimentary to one another, easy to join

Question 3

Whats a pro and con of using restriction endonuclease

Answer 3

-pro: easy to use
-con: leaves introns present

Question 4

What closes the gap with cleaved genes and plasmids?

Answer 4

DNA ligase

Question 5

How does reverse transcriptase work?

Answer 5

-sourced from retroviruses
-causes the mRNA to become double stranded cDNA

Question 6

Pros and cons of reverse transcriptase?

Answer 6

-pro: intron-free
-con: needs specialist skills