Manipulation of DNA - Restriction enzymes Flashcards
1
Q
what is an exonuclease and endonuclease
A
an exonuclease cuts at the ends of strands
endonucleases cut within the strand
2
Q
how were restriction enzymes discovered and what purpose did they serve
A
they were isolated in the 50s and acted as an immune system cutting phage dna
3
Q
what are some characteristics of type ii restriction enzymes
A
site specific
4-6 recognition site
sites are pallendromic
can produce both blunt and sticky ended sites
4
Q
how can you prevent endonuclease activity and what are some enzymes that do this
A
by methylating the dna you can prevent cutting, this can be done with dam or dcm
