Genetic engineering (4.6.2.4) — AQA GCSE Biology Revision Notes

Revision notes for AQA GCSE Biology specification point 4.6.2.4, Genetic engineering.

Genetic Engineering

  • GENETIC ENGINEERING involves modifying the DNA (genome) of an organism by introducing a GENE that codes for a DESIRED CHARACTERISTIC from ANOTHER organism.
  • The gene is inserted into the organism at an early stage in their development so that it develops with the DESIRED CHARACTERISTICS.
  • This is done by transferring the gene using a VECTOR. The vector can either be a VIRUS or a PLASMID from a BACTERIA.

 

USES OF GENETIC ENGINEERING

1. Producing MEDICINES, such as INSULIN for DIABETES treatment.

2. Creating GENETICALLY MODIFIED (GM) CROPS with enhanced RESISTANCE to disease, herbicides and insects.

3. Creating GENETICALLY MODIFIED (GM) CROPS with BIGGER and BETTER FRUIT.

4. Modifying the genes of ANIMALS, so that they produce substances like drugs in their milk.

5. Carrying out GENE THERAPY which aims to correct GENETIC DISORDERS caused by FAULTY GENES by replacing them with WORKING GENES into patients' cells.

 

STEPS FOR GENETIC ENGINEERING

1. The beneficial gene is ISOLATED and 'CUT OUT' from an organism's genome using ENZYMES.

2. The gene is INSERTED into a VECTOR (virus or a bacterial plasmid).

3. The vector with the gene is then introduced into the target organism.

4. The target organism now expresses the BENEFICIAL CHARACTERISTICS coded by the inserted gene.

 

As an example, lets look at making insulin from bacteria. This involves using a BACTERIAL PLASMID and adding the gene responsible for making INSULIN from a HUMAN CELL.

 Genetic Engineering

The bacteria cell are capable of making insulin and by reproducing them, you can make high volumes of insulin that can be used to treat DIABETES.

  

CONTROVERSY WITH GM CROPS

  • There's a debate about the potential long-term effects of genetic engineering on organisms and ecosystems. Here are some of the advantages and disadvantages of using GENETICALLY MODIFIED CROPS.

GM Crops

 

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