recombinant DNA

Question 1

what is recombinant DNA?

Answer 1

= artificial modification of DNA

- DNA is either added or removed from the cell

Question 2

what are the functions of recombinant DNA?

Answer 2

• introducing genes for the desired trait
• using harmless bacteria to produce proteins
• replace faulty genes

Question 3

define a transgenic orgnanism

Answer 3

one species of DNA is introduced into a different species

Question 4

what is the aim of transgenic organisms?

Answer 4

• introduce a trait that is not normally present

Question 5

5 steps of making recombinant DNA

Answer 5

1) isolate the gene of interest (blunt ends)
2 cut out genes using restriction enzyme to produce sticky ends
3) isolate plasmid from the bacterium
4) cut once using the restriction enzyme
5) put the gene into a plasmid
6) use ligase to join two sections

Question 6

what are restriction enzymes?

Answer 6

= enzyme that cuts strands of DNA at a specific sequence of nucleotides
- recognize base sequence and cut at a certain point

Question 7

define the recognition site

Answer 7

a specific sequence of nucleotides at which an enzyme cuts a strand of DNA

Question 8

what is a blunt end?

Answer 8

• when both strands terminate in a base pair
• caused by a straight cut
• restriction enzyme makes a clean break across a strand

Question 9

what is a sticky end?

Answer 9

• a stretch of unpaired nucleotides in the DNA molecule that overhang at the break in the strand
• caused by a staggered cut

Question 10

what is DNA ligase?

Answer 10

• joins fragments together through ligation
  = joins the phosphate group at the end of one strand to the sugar molecule at the other strand
• joins the backbone after the complementary bases are first joined by hydrogen bonds