Genetic Engineering (Human Insulin)

Question 1

1.

Answer 1

mRNA is extracted from beta cells in Islets of Langerhan of pancreas.

Question 2

2.

Answer 2

mRNA converted to DNA using reverse transcriptase. DNA polymerase turns single-stranded DNA to double-stranded.

Question 3

3.

Answer 3

DNA is cut using restriction endonuclease, leaving sticky ends.

Question 4

4.

Answer 4

Plasmids from bacteria are cut open using the same restriction enzymes so the sticky ends of plasmid are complementary to those of human DNA.

Question 5

5.

Answer 5

Plasmid and human gene for insulin are joined by DNA ligase, binding complementary sticky ends.

Question 6

6.

Answer 6

A recombinant DNA plasmid has been formed, including a genetic marker on gene coding for penicillin resistance.

Question 7

7.

Answer 7

Bacteria is mixed with recombinant plasmids and given Ca2+ and heat shock to take up plasmids. This forms transgnic bacteria.

Question 8

8.

Answer 8

Transgenic bacteria is selected by growing all bacteria in the presence of penicillin. Only the bacteria that have taken up the recombinant plasmid survive and they are grown in large scale fermenters via continous culture.

Question 9

9.

Answer 9

Insulin (primary metabolite) is extracted and purified from culture.