Biology Module 6- (Part 1)

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Created by: Ellie.M
Created on: 23-03-15 19:29

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Biology Module 6- (Part 1)
- Yeast: Yeast is a single celled fungus that is grown for many functions. Its growth rate can also be altered by; changing food availability, changing temperature, changing pH, removing waste products.
  - The growth rate of yeast doubles for every 10c rise in temperature until the optimum is reached.
- Bacteria: Bacteria cells have certain features that allow them so survive, these include: a flagellum (used for movement), a cell wall (to maintain shape and stop it from bursting), DNA (to control the cells activity and replication of the cell)
  - Bacteria cells can be different shapes such as spherical, rod shaping, spiral or curved rods. Bacteria reproduce by splitting in to two in a type of asexual reproduction called binary fission. It is possible to get bacteria to reproduce on an agar plate, this is called aseptic technique.
    - Bacteria can live in a very wide range of of habitats. They can reproduce very quickly.
- Sir Alexander Fleming discovered penicillin.
  - Joseph Lister invented the first antiseptic using carbonic acid to prevent wounds becoming infected.
- Yogurt Making: Firstly the equipment all needs to be sterilised, then the milk needs to be pasteurised by heating it at 78c, When the milk is cooled down it is incubated with a culture of bacteria. This is then followed by by sampling and then adding flavours, colours, and packaging
  - The type of bacterium that is added to the milk is Lactobacillus, this causes the breakdown of lactose in milk to lactic acid, this makes the yoghurt acidic.