Biotechnology - Biotechnology & GM Foods (GCSE Biology)

Biotechnology & GM Foods

Biotechnology

Biotechnology and Food

Biotechnology is harnessing technology to develop and alter living organisms. It is used to suit the demands of our growing population. Cloning and genetic modification are examples of biotechnology.

Biotechnology can be used in food production. Some examples are below:

Yeast and Bread

Yeast is a type of fungi and it can help make bread.

1. Yeast is mixed with flour, water and some sugar and left covered in a warm place to help the dough rise.
2. The carbohydrates in the flour are broken down by the enzymes to make sugars.
3. These sugars are used by the yeast for aerobic respiration and carbon dioxide is produced.
4. Once the oxygen is used up, the yeast starts to anaerobically respire to produce ethanol and carbon dioxide. This is known as fermentation.
5. The carbon dioxide becomes trapped in the bread and forms bubbles which causes the dough to rise.
6. When the bread is baked at high temperatures, the yeast is killed and the ethanol boils off. As the yeast has been killed, the bread stops rising but the pockets of air still remain.

You can investigate the rate of anaerobic respiration and carbon dioxide production in different conditions e.g. temperature.

You can do this by mixing yeast with some sugar and distilled water in a test tube then adding a layer of oil on top to provide anaerobic conditions. A bung can be attached with a tube going into another test tube with water. The yeast tube can be placed in a water bath of differing temperatures and you can time how many bubbles are produced in a minute in the second test tube. You will see that the number of bubbles produced changes with the temperature.

Bacteria and Yoghurt

Bacteria can be used to ferment milk in order to make yoghurt.

Remember fermentation is when microorganisms break down sugars to release energy usually via anaerobic respiration.

1. The equipment being used is sterilised.
2. The milk is heated to 72°C for 15 seconds then it is cooled again.
   This is pasteurisation and it is used to kill harmful microorganisms.
3. Lactobacillus bacteria is added to the milk.
4. It is heated to 40°C and incubated in a fermenter.
5. Lactic acid is produced as the bacteria ferment the lactose sugar in the milk.
6. The lactic acid is what causes the milk to become solidified and clotted to form yoghurt.

Lactase and Lactose-Free Milk

Lactose is a type of sugar that can be found in milk. It is broken down by the enzyme lactase.

Some people are lactose-intolerant. This means their bodies are unable to produce the enzyme lactase hence, they cant digest the lactose in milk.

Lactase can be added to milk so that the lactose is broken down into glucose and galactose. This helps produce lactose-free milk.

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Other Examples of Biotechnology

• Pectinase can be used in fruit juice production. Pectinase is an enzyme produced by fungi and bacteria that breaks down the pectin in plant cell walls to aid the decomposition of fruit and vegetables. Hence, pectinase is used to breakdown fruit to produce juice.
• Enzymes can be used in biological washing powders. The enzymes help breakdown material and remove stains. Biological washing powders are more effective at lower temperatures than non-biological washing powders as they contain enzymes.
• Yeast can be used to make biofuels. Living material (biomass) can be broken down into sugars. The sugars can then be broken down in fermenters using yeast to produce ethanol via anaerobic respiration. The ethanol produced is used as a biofuel.
• The fungus Penicillium can help produce the antibiotic penicillin. This fungus produces penicillin. The fungus is grown in industrial fermenters on a huge scale to mass produce penicillin as it is one of the most commonest antibiotics used. The fermenters themselves contain a culture medium in which the fungus grows and reproduces. Optimum conditions are maintained within the fermenter to get a large yield of penicillin. Conditions controlled include pH, oxygen levels, provision of nutrients and the vessels are heated from time to time to kill unwanted microorganisms. This increases the yield of penicillin as the Penicillium don’t have to compete with other microorganisms for nutrients.

Genetically Modified Organisms (GMOs)

GM and Food

• Transgenic organisms are created. We have already discussed how genes are inserted into other organisms. An organism with that has the DNA of another organism inserted into it is known as a transgenic organism.
• Insulin is produced by a GMO. As discussed earlier, insulin is made from a genetically modified organism. E Coli has been used to make it. The insulin then has to be purified for human consumption.
• GMOs can also be used to produce food. The fungus Fusarium is genetically modified to produce a high in protein supplement food for vegetarians. This protein is called mycoprotein and is grown in a fermenter. The conditions are kept at the optimum, for example the temperature is controlled by a water jacket and oxygen is piped in to prevent anaerobic respiration. Moreover, the pH is kept constant. Glucose syrup is added as food and the mixture is agitated by paddles to allow the optimum growth. The food then grows and is harvested.
• Golden rice is produced. We discussed golden rice earlier, but it is a GMO.
• GMOs have been used to produce crops that have resistance against many conditions. Crops can be made that are resistant to insects and pesticides. This increases yield greatly.