B7.4

We can grow bacteria and fungi on a large sclae using fermenters, we call this process fermentation.

products made this way include:

- antibiotics.

- single-cell protein: microbes grown for food.

- Enzymes fro food manufacture. E.g. rennin for making cheese.

some of these are made using genetically modified microorganisms.

when scientists genetically modify and organism, they alter of modify its characteristics by transferring genes from another organism into its DNA.

Scientists:

1. find the gene that they want to transfer from one species to another.

2. cut it out using enzymes.

3. make lots of copies of the gene.

4. then transfer the copies to cells of the other species.

They use a vector (carrier), a virus or plasmid, to transfer the genes.

some exmaples of genetic modifcation include:

- modifying microorganisms for making, drugs such as antibiotics and hormones such as insulin.

- modifying crop plants to make them resistant to pests and diseases.

scientists can use genetic testing to identify fualty alleles in:

- adults

- fetuses

- IVF embryos

Disorders that they can idntify include cycstic fibrosis and huntingtons disorder. They use a special piece of DNA  called and gene probe. This is a single strand of DNA with bases that will pair with the faulty allele.

1. take a blood sample.

2. isolate the white blood cells.

3. Extract the DNA from the white blood cells. Use enzymes to cut the DNA into pieces.

4.heat gently to separate the DNA into single strands.

5. then add the gene probe.

6. If the faulty allele is present it sticks to the gene probe and is detected using UV light or X-ray film.

The DNA probe has matching bases to the part of the gene being tested for.