Why bacteria are usefulSpec 21.1.1, 21.1.2
In short
Bacteria are useful in biotechnology and genetic modification because they have a rapid reproduction rate and can make complex molecules such as proteins. A large population, and a lot of product, is made in a short time. There are also few ethical concerns over growing them, and their plasmids allow genes to be inserted into them.
Biotechnology is the use of living organisms, or substances made by them, to make useful products or to carry out useful processes. Bacteria are used a great deal, both in biotechnology and in genetic modification.
Bacteria are useful because of two features. They have a rapid reproduction rate, so a large population is made in a short time. They also have the ability to make complex molecules, such as proteins. Once genetically modified, they can make human proteins such as insulin.
| Reason | What it means |
|---|---|
| Rapid reproduction rate | Bacteria divide very quickly, so a large number of cells, and a large amount of product, is made in a short time |
| Make complex molecules | Bacteria can make proteins and other complex molecules that are difficult to make in other ways |
Supplement (what this means)
Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels meanFurther reasons
Supplement (what this means)
Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels mean- Few ethical concerns. There are few ethical concerns over manipulating bacteria and growing them in large numbers, unlike the use of animals.
- Plasmids. Bacteria contain plasmids, small circular loops of DNA separate from the main bacterial DNA. A gene can be inserted into a plasmid, and the plasmid can then be put into a bacterium.
If asked why bacteria are useful in genetic modification, give the feature and link it to the result: for example, they reproduce rapidly so many copies of the gene and a lot of product are made quickly.
Written and checked against the Cambridge IGCSE Biology (0610) specification · Updated October 2026