Recombinant DNA Technology

Question 1

what is the purpose of recombinant DNA technology

Answer 1

make copies of DNA, cut DNA molecules into shorter fragments, join DNA molecules together in combinations not seen in nature

Question 2

write a note on restriction endonucleases

Answer 2

this is an enzyme that binds to a DNA molecule at a particular recognition site that makes a specific double stranded cut at or near the sequence

Question 3

what is the biological significance of restriction endonucleases

Answer 3

can provide the bac with protection against foreign DNA - bac DNA is methylated by methyltransferase enzyme and the non bac DNA lacks methyl groups and is digested by the restriction endonuclease

Question 4

what are the three types of RE and how do they work

Answer 4

types 1 and 3 cut randomly asround the target
type 2 always cuts at the same position either within or near the recognition site- predictable activity

Question 5

what are the two types of cuts that RE cut DNA into

Answer 5

blunt end- simple double stranded cut
stick ends- cut the two DNA strands at different positions resulting in an overhang that is usually 2-4 nucleotides apart

Question 6

what is a unique feature of recognition sequences

Answer 6

they are palindromic