National 5 Biology Genetic Engineering

Genetic Transfer

• • • It is possible to transfer genetic information from one cell to another.

In bacteria there is a chromosome which is circular and smaller circles of DNA called plasmids.

The chromosome and the plasmids are made of DNA.

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Genetic Transfer

• • • When bacteria divide, the chromosome and the plasmids are replicated.

Genetic information can be passed from one cell to the next naturally.

It can also be passed from one cell to the next artificially by genetic engineering.

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Genetic Transfer

• • • Viruses require living cells before they can replicate.

When a virus attacks a cell its DNA is injected into the host cell.

This means that the viruses DNA and the host cell’s DNA become joined.

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Genetic Transfer

• • When the host cell divides by mitosis, the virus’s DNA is also copied.

Using this knowledge, we can now alter the genetic code of cells using genetic engineering.

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Genetic Transfer

• • An organism which has been altered in this way is described as being genetically modified.

In this way, we can ‘programme’ bacterial cells to produce things that they would not normally produce.

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Genetic Engineering Stages

• • • • Identify the section of DNA containing the gene we require.

Cut the gene out using an enzyme. (genetic scissors) Remove the plasmid from the bacterial cell.

Using the same enzyme, open the plasmid,

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Genetic Engineering Stages

• • • • Insert the gene into the plasmid using another enzyme (genetic glue).

Replace the plasmid into the bacterial cell.

Allow the bacterial host cells to divide naturally.

The bacterial cell will now produce the protein we want which was coded in the original DNA.

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Genetic Engineering

• • • This process of genetic engineering can be used to produce such proteins as insulin, which is required to treat diabetes.

It has also been used to produce human growth hormone.

Other examples include more nutritional plant products and disease resistance.

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Genetic Engineering

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