Module 6: Genetics, Evolution And Ecosystems

Question 1

How are microorganisms used in baking?

Answer 1

yeast is mixed with sugar and water which allows it to aerobically respire, producing carbon dioxide which allows bread to rise

Question 2

How are microorganisms used in beer brewing?

Answer 2

when barley germinates it produces enzymes that break starch into sugars that yeast can use. The barley seeds are then killed to produce malt. The malt is mixed with hot water to produce wort. The wort is then mixed with yeast and heated to anaerobic conditions so the yeast respires anaerobically to produce alcohol. The beer is then matured, filtered, pasteurised and then bottled/canned

Question 3

How are microorganisms used in cheese making?

Answer 3

first milk is pasteurised(heated to 95°C to kill off bacteria) and then homogenised(fat droplets evenly distributed across the milk). The milk is then added to a culture of bacteria which feed on the lactose and separates the milk into solid curds and liquid whey. The curds can then be cooked either in or separate from the whey to produce cheese

Question 4

How are microorganisms used in yoghurt making?

Answer 4

skimmed milk powder is added to milk which is then pasteurised and cooled down. A culture of bacteria containing 50% Lactobacillus bulgaricus (which produces ethanal when fermented) and 50% Streptococcus thermophilus (which produces lactic acid when fermented) is added to the mixture and heated so they respire anaerobically, fermenting and producing the polymers that give yoghurt its thick, smooth texture

Question 5

How are microorganisms used to produce penicillin?

Answer 5

Commercial production didn’t begin until the discovery of P. chrysogenum. This fungus needs high oxygen levels and a rich amount of nutrients to produce enough penicillin. The fungus is grown in a growth medium that contains a buffer to keep its pH around 6.5. The mixture is constantly stirred to keep the fungus oxygenated and contains a rich nutrient medium

Question 6

How are microorganisms used to produce insulin?

Answer 6

insulin was originally taken from the pancreas of animals which caused rejection and allergic reactions. In the late 1900s though, scientists managed to genetically modify bacteria to produce pure human insulin. The bacteria are grown in a fermenter and downstream processing results in a constant supply of insulin used to help people with type 1 diabetes manage their blood glucose levels

Question 7

How are microorganisms used in bioremediation?

Answer 7

Nutrients are placed on organic wastes such as oil spills to encourage microorganisms to culture there and break down the organic substances into carbon dioxide and water. Genetically modified bacteria have been made to take in mercury to reduce mercury contamination in water