Genetic Modification
Genetic modification changes an organism's DNA by inserting a gene from another organism. To make human insulin: the gene is cut out with restriction enzymes, leaving sticky ends; a bacterial plasmid is cut with the same enzyme; DNA ligase joins the gene into the plasmid (recombinant plasmid); the plasmid is put into bacteria, which multiply in fermenters and make insulin. GM crops can be pest-resistant, herbicide-resistant or have added nutrients (Golden Rice, vitamin A). Concerns include effects on wild populations and food safety.
Learning objectives
- Define genetic modification.
- Describe how a human gene is inserted into bacteria.
- Give examples of GM organisms and evaluate their use.
Why are bacteria able to make a human protein like insulin?
Core idea
Millions of people with diabetes inject insulin made by bacteria carrying a human gene.
Genes can be cut from one organism and inserted into another using restriction enzymes, ligase and a vector. The new organism makes the protein the gene codes for.
1. Making GM bacteria
Cut, paste, insert, grow.
Should a country grow insect-resistant GM cotton?
- Goal
- Balanced evaluation.
- Strategy
- Advantages vs risks.
- Economic and environmental gains.
- Ecological and economic risks.
Why is human insulin from GM bacteria better than pig insulin?
Summary
- Restriction enzyme, ligase, plasmid.
- GM bacteria make insulin.
- GM crops: benefits and concerns.
- Restriction enzyme
- Enzyme that cuts DNA at a specific sequence.
- DNA ligase
- Enzyme that joins DNA fragments.
- Recombinant DNA
- DNA combining genes from different organisms.
Create a free account to read the rest of this lesson: key formulae, worked examples, explore the graph, common mistakes, exam tip, guided practice and more. Your answers are checked and your progress is saved.