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From St Gabriel's Prelim 2008
Through advances in biotechnology, human insulin can be mass produced by using genetically modified bacterium. The principle steps are outlined below:
(a) How is the insulin gene removed from the chromosome (stage 1)?
(b) What is the ring of DNA called?
(c) How are stages 2 and 3 accomplished?
(d) Stage 4 is carried out in a fermenter. Suggest 2 precautions that the technicians handling the fermenter should take note of and explain why you think the precautions are important.
(e) The bacterium multiplied to produce many copies of itself. What is another term for each copy of the original bacterium?
(f) How does stage 4 contribute to the mass production of human insulin?
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Answer: (a) Through the use of restriction enzymes
(b) Plasmid
(c)
(stage 2)Use of ligase to join the sticky ends of plasmid and insulin gene
(stage 3) Mixing bacteria with recombinant plasmids. Pulses of electricity are passed through bacterial cells to increase chances of uptake of the plasmids
(d) Ensure factors are kept optimal; factors such as
- oxygen (aeration)
- pH (maximum growth of bacteria)
- temperature (to prevent death of bacteria from overheating)
- nutrient concentration (nitrogen, carbon content and mineral salts should be sufficient for growth and multiplication of bacteria) [Any 2 of the above points]
Technicians should ensure that culture broth is sterile to prevent contamination of bacterial culture and product.
Ensures that impeller is working so that nutrient broth and oxygen are well distributed.
(e) Clones
(f) The insulin gene is multiplied as transgenic bacterium multiplies. Each clone of the transgenic bacterium is able to produce insulin
