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Bacteria (Bacteria (Things that are unique to bacteria (Slime capsule…

- - - - This stops the cells from drying out. This also protects the cells from attack’s from other cells and lets them bind onto host cells.
    - - Free floating DNA
    - - Extra loops of DNA in bacteria
  - - - In this process the DNA molecule makes an identical copy
        of itself and then divides the cell in two. This forms two cells. (One is new). These two cells are called daughter cells. The process of forming the two identical cells is called mitosis.
    - - Warmth of around 28-30 C. Look at above point for reasons
      - Water for chemical reactions in the cell
      - Nutrients like glucose and amino acids
      - Mineral ions
      - A lot of bacteria also require oxygen for respiration to produce energy and survive, although some don’t and are called anaerobic bacteria.
    - - Remember first to sterilise
        equipment using aseptic techniques.
        
        Pasteurise milk at at least 65 C. This heat kills any pathogenic bacteria that may be in the milk.
        
        Cool milk and add bacterial culture (for yogurt it is Lactobacillus).
        Cool milk so lacto isn’t killed.
        
        Leave milk to 28 C and leave
        for a few hours. The bacteria will multiply as they can feed of
        the lactose in the milk. Lactose is a food source. When multiplying the bacteria converts the lactose to lactic acid which curdles the milk making it yogurt.
        
        Samples are taken to test
        if ready
        
        Cool to 5 C
        
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        Ways that lacto prevents other
        bacteria growing in yoghurt that may be pathogenic
        
        Bacteria lowers the pH by
        excreting acid which other bacteria can’t survive in
        
        They are able to grow and out compete
        other bacteria in acidic conditions
        
        They eat up sugars in the milk before other
        bacteria gets there meaning the other bacteria isn’t able to grow as much and take out larger colony of lacto
        
        Asceptic techniques include
        
        Wipe down workbench before starting
        
        This is so no bacteria on workbench can get into petri dish that could kill bacteria you are trying to grow.
        
        Work near a yellow Bunsen flame
        
        This creates a convection current that pushes any bacteria in the
        air away from the Petri dish. Yellow so you can see it and don’t accidentally burn yourself.
        
        Sterilise metal implements
        
        Do this by heating with a hot Bunsen flame
        
        Autoclaving
        
        This is a saturated steam under a high pressure
        
        Chemical sterilants
        
        Ethylene gas kills bacteria
  - - - Cytoplasm
      - Cell membrane
      - Cell wall
        
        In bacteria cell walls are made of peptidoglycan
        
        Cell wall is a permeable membrane that lets everything through and supports the structure of the cell.
      - Flagellum which moves the cell