Use of Biological Resources · 6 question types
Past paper frequency (2018 to 2024)
This topic accounts for approximately 10% of your exam marks.
Insulin production by bacteria and GM crops are growing in exam frequency.
Genetic engineering (also called genetic modification, GM) is the process of deliberately changing an organism's DNA by inserting a gene from a different organism, usually to give it a useful new characteristic
In selective breeding (topic 17), the alleles being shuffled around already exist within the species. Genetic engineering goes much further: it lets scientists take a gene from any species and insert it into the DNA of any other species. This is possible because the genetic code is universal: every living thing uses the same four DNA bases (A, T, G, C) and the same code (three-base codons) to specify amino acids. A human gene placed inside a bacterium still codes for the same human protein.
| Term | Meaning |
|---|---|
| Genetically modified organism (GMO) | Any organism whose DNA has been deliberately altered |
| Transgenic organism | A GMO that contains DNA from a different species (a subset of GMOs) |
| Recombinant DNA | DNA that has been built from pieces of more than one source organism |
| Vector | A "carrier" molecule used to insert the new gene into the host cell. Usually a bacterial plasmid or a virus |
| Restriction enzyme | A bacterial enzyme used to cut DNA at specific base sequences |
| DNA ligase | An enzyme used to join two pieces of DNA together |
A useful memory aid: picture restriction enzymes as the scissors that cut DNA, and ligase as the glue that joins it back together.