1. yeast
   1. what is it
      1. microorganism
      2. single celled fungus
      3. structure
   2. respiration
      1. anaerobic
         1. glucose ----> ethanol + CO2 + energy
         2. fermentation
      2. aerobic
         1. glucose + water ---> CO2 + H2O + energy
         2. grow
         3. reproduce
2. yeast uses
   1. bread
      1. put in dough
      2. CO2
         1. bread rises
         2. trapped in dough
   2. alcoholic drinks
      1. beer
         1. brewed
         2. grain
         3. 1/ barley grains germinate
            1. starch ----> sugar by enzymes
         4. 2/ malting
            1. grains dried in kiln
         5. 3/ mash malted grains
            1. add water
            2. seive
            3. sugar solution left
         6. 4/ add hops
            1. bitter flavour
         7. 5/ ferment sugar solution with yeast
            1. sugar ----> alcohol
      2. wine
         1. yeast uses the natural sugars of the grapes
3. cheese
   1. 1/ culture bacteria added to milk
   2. 2/ solid curds
   3. 3/ curds separated from liquid whey
   4. 4/ more bacteria added to curds
   5. 5/ ripen
   6. 6/ add mould if wanted : blue cheese (stilton)
4. yoghurt
   1. bacteria clots the milk
   2. 1/ heat treat milk to kill bacteria
   3. 2/ starter culture added
      1. ferment lactose sugar to lactic acid
   4. 3/ acid causes milk to clot : yoghurt
   5. 4/ add sterilised flavours