Learning focus
Use precise biological vocabulary, interpret diagrams and data, explain mechanisms as linked sequences, and evaluate biological applications and environmental decisions.
Inserted gene
The human gene controlling insulin production is inserted into bacterial DNA, commonly using a plasmid. The modified bacterium reads the genetic information and makes human insulin protein.
Large-scale growth
Modified bacteria are grown in fermenters under controlled temperature, pH, oxygen and nutrient conditions. Rapid reproduction produces many cells, each able to synthesise the protein.
Harvest and purification
Insulin is separated from cells or culture medium and purified to medical standards. Strict quality control is essential because contamination or incorrect protein structure could be harmful.
Advantages
The process can provide a reliable, large supply of human insulin with consistent composition. Production does not depend on extracting insulin from animal organs and can be scaled according to demand.
Practical or data skill
Trace the process from human gene to purified product, identifying where genetic modification ends and industrial fermentation begins.
Examination tip
Bacteria are modified to make insulin; insulin itself is not a bacterium or gene.
Review questions and suggested answers
Question 1
Which gene is inserted?
Suggested answer
The human gene controlling insulin production.
Question 2
Why are fermenters used?
Suggested answer
To grow large numbers of modified bacteria under controlled conditions.
Question 3
Why is purification required?
Suggested answer
To obtain safe, medically usable insulin free from contaminants.
