Microorganisms
Microorganisms are very tiny organisms that can only be seen in detail using a microscope. Many microorganisms are unicellular which means they exist as a single cell.
Examples of microorganisms include:
- bacteria
- yeast (a type of fungus)
Microorganisms can be used by humans to produce foods and other useful substances. They are suitable for this role because they grow rapidly, may have simple nutrient requirements and can produce a wide range of products.
Using yeast to make bread and beer
Yeast is a single celled, microscopic fungus that uses sugar as food. In bread making, the carbon dioxide produced by the yeast during respiration is trapped in the dough, causing it to rise.
In the image below, you can see how much one batch of dough has risen after it has been left to rest.
In brewing, A gaseous compound of carbon and oxygen, which is a by-product of respiration, and which is needed by plants for photosynthesis. and ethanol (alcohol) are produced by the yeast during A term for respiration in the absence of oxygen. (The chemical change that takes place inside living cells, which uses glucose and oxygen to release the energy that organisms need to live. Carbon dioxide is a by-product of respiration. without oxygen).
Beer contains alcohol and the carbon dioxide gives the beer its characteristic fizz.