Genetic Engineering (T5)

Question 1

Describe the stages involved in the production of the hormone insulin, by process of genetic engineering…

Answer 1

• select human cells that contain genes for insulin
• remove from the cell the relative section of the chromosome that contains the genes for insulin
• the gene which codes for insulin is cut from the chromosome using specialised enzymes called ‘restriction endonuclease enzymes’
• a bacterial cell is selected, containing DNA in the form of circular plasmids
• the plasmids are extracted from the bacterial cell and used as vectors to introduce the gene for insulin into the bacterial cell
• plasmids are then cut open using the same ‘restriction endonuclease enzymes’
• the human insulin gene is then inserted into the cut region of the plasmids using another specialised enzyme called a ligase enzyme
• this DNA is now described as a recombinant DNA
• plasmid containing the recombined DNA is reinserted back into the bacterial cell
• the bacterial cell is allowed to reproduce in a fermenter
• all the bacterial cells produced contain the plasmids with the human insulin gene

Question 2

What is the genetic engineering of human insulin useful for?

Answer 2

For people with diabetes as it provides insulin, allowing them to control blood sugar levels

Question 3

What are ‘restriction endonuclease enzymes’ and what is their nickname?

Answer 3

They are specialised enzymes which can ‘cut’ genes from chromosomes and cut plasmids.

Also known as ‘genetic scissors’.

Question 4

What is a ligase enzyme?

Answer 4

A specialised enzyme that can insert genes into cut plasmids.

Nicknamed the ‘genetic glue’.