GCSE Biology Unit 3 : Micro-organisms

Micro-organisms

In industry

Making alcohol and bread:

• A type of fungus called yeast is used, it is a single-celled organism
• When it respires anaerobically(without oxygen) it produces CO2 and ethanol
• ie. Yeast + Glucose > Ethanol + CO2

In the production of beer:

• Barley grains are soaked in water and kept warm(this is called malting)
• Enzymes are used to break down the starch into a sugary solution
• The solution is extracted and used as an energy source for the yeast
• This is then fermented to produce ethanol
• Hops are added for flavour

Making yoghurt:

• A type of bacteria is used
• When it respires anaerobically it produces lactic acid
• ie. Bacteria + Glucose > Lactic acid

Firstly:

• Skimmed milk is heated to 80 degrees for 15 seconds(this is called pasteurising) which destroys unwanted microbes in the milk
• A starter of bacteria…