Flashcards in B3 Topic 3 - Biotechnology Deck (16)
What conditions are needed in fermenters to efficiently grow microorganisms?
Supply of nutrients:
Nitrates (to make proteins)
Vitamins and Minerals
Air must be pumped in (for aerobic microorganisms)
Temperature must be regulated for enzymes to work efficiently (usually controlled with a water jacket)
pH must be monitored so that it is optimal for the microorganisms
Sterile conditions so that there is no contamination from other microorganisms
A motorised stirrer should keep the culture well mixed
What are Mycoprotein used for?
Mycoprotein comes from fungi and is used as a substitute for meat in vegetarian meals. The fungus is grown in a fermenter and then used to make food. It is much healthier than meat as it contains more protein and fibres, and has less fat.
How is fermentation used to make yoghurt from milk.
The milk is first pasteurised (heated to a high temperature to kill bacteria) and then cooled.
A culture of Lactobacillus bacteria is added and the mixture is incubated at 40°C in the fermenter.
The bacteria ferment the lactose sugar in the milk into lactic acid, which causes the milk to clot and solidify into yoghurt.
Flavours/fruits etc. are then added.
State some advantages of using microorganisms in food production.
Microorganisms grow very quickly
Easy to look after
Not dependant on seasons such as plants
They can use waste products from agriculture and industry as food
How are enzymes used in biological washing powders?
Carbohydrates - amylases - converted into simple sugars
Lipids (fats) - lipases - fatty acids and glycerol
Proteins - proteases - amino acids
All the products are soluble in water and can therefore be washed away easily.
Biological washing powders can work at much lower temperatures, but may be affected more easily by pH.
Give two examples of enzymes used to make foods.
Chymosin - replaces rennet to make cheese, rennet came from the lining of a calf's stomach, not suitable for vegetarians, chymosin manufactured on a large scale with yeast.
Invertase - used to make sweets, converts sucrose in to glucose and fructose which are sweeter, less sugar needed for same sweetness, saves money.
What is the immobilisation of an enzyme?
When an enzyme is used to speed up a reaction, it usually ends up dissolved in the mixture and can be difficult to remove.
Immobilised enzymes are attached to an insoluble molecule such as fibres, or encapsulated in alginate beads. The insoluble material can be washed and then reused.
How can bacteria be engineered to produce human insulin?
1. A plasmid is removed from the bacterium.
2. The insulin gene is cut out of a human chromosome using restriction enzyme, which recognises the specific sequences of DNA and cuts it at these points.
3. The plasmid is cut open with the same restriction enzyme, leaving the same sticky ends.
4. The plasmid and the human insulin gene are mixed together and then joined with ligase. This joins the sticky ends together to create recombinant DNA.
5. The recombinant DNA is inserted into a bacterium.
6. The bacterium is grown in a fermenter.
How can bacteria be engineered to genetically modify plants?
1. The bacterium Agrobacterium tumefaciens invades plant cells and inserts its own genes into the plants DNA.
2. The wanted gene is cut out from the DNA of a plant cell.
3. The gene is inserted into the DNA of the bacterium.
4. The bacterium is then allowed to infect the cells of the target plant.
5. The bacteria insert their genes into the plant cells.
6. These new plant cells are the grown on a large scale.
How can crops be engineered to be resistant to insects?
1. The bacterium Bacillus thuringiensis (Bt) produces a toxin that kills many insect larvae that are harmful to crops.
2. The gene for Bt toxin is inserted into crops which then produce it in their stems and leaves, making them resistant to insect pests.
State the advantages and disadvantages of using biotechnology to provide food for people in developing countries.
Improved crop yields - pest resistance, grow better in drought conditions
Can be used to combat deficiency diseases - Golden Rice produces a chemical which is converted into vitamin A in the body
Problem isn't that there isn't enough food, rather that people don't have enough money to buy food, tackle poverty instead
Countries may become dependant on companies who sell GM seeds
Poor soil is main reason that crops fail, GM won't survive either
Biotechnology is the use of living organisms to produce useful products or to provide people with services.
State the advantages and disadvantages of using biotechnology to help with health problems for people in developed countries.
Flavonoids are molecules that have antioxidant effects which are thought to protect against cancers and heart diseases. Snapdragon flowers contain a type of flavonoid. Scientists have managed to genetically engineer tomatoes to contain the flavonoid gene, making purple tomatoes. They have been developed as an easy way of getting antioxidants for people who don't eat enough fruit and vegetables.
The flavonoid has changed the colour of the tomatoes.
There might be some unforeseen long-term side effects of GM crops.
What three methods are there of increasing food production to match the rise in global population?
1. Reducing pest numbers - less pests means that crops can grow larger. Farmers can use insecticides to kill insects which damage the crops. Plants can also be genetically modified to produce toxins that kill pests. Crop rotation, where different crops are grown in a field each year, helps prevent pests which affect that particular crop from building up. Biological control also works, where living things are used rather than chemicals. E.g. Ladybirds to kill aphids
2. Selective breeding programmes - selective breeding is when humans breed the plants with the most desirable characteristics to develop the desired traits. E.g. Largest wheat plants are bred together, over many generations, the offspring will be much larger
3. Genetically modifying plants
Give three examples of biofuels and briefly describe them.
Biogas - microorganisms usually decompose waste material or plants to produce biogas. It is usually about 70% methane and 30% carbon dioxide. It can be burned to power a turbine or to heat heat water to heat a central heating system. It can also be used as fuel for cars and buses.
Biodiesel - biodiesel is an alternative fuel, similar to regular diesel. It is made from vegetable oils, animal fats or waste cooking oil.
Ethanol - it can be burnt as a fuel and is much cleaner than petrol or diesel as it releases much fewer pollutants. It is produced from the fermentation of glucose with yeast. Sugar cane, sugar beet, corn and barley can all be used as the source of glucose. Cars can be adapted to use a mixture of ethanol and petrol.