Bacteria were unicellular. Found almost everywhere e.g. : water, soil, plants, animals and humans. There are two types :> Pathogenic ( disease causing) and Non - Pathogenic
Conditions for Growth
Food: Bacteria can be > Saprophytic: Feeding on non living matter causing spoilage e.g. lactic acid bacteria spoils milk. > Parasitic: Feed on living matter such as animals and humans causing disease e.g. Staphylococcus Aureus causes staph infections on the skin.Oxygen: Bacteria can be : > Aerobic: e.g. Mycobaterium Tuberculosis >Anaerobic: e.g. Clostridium botulinum. > Faculative: e.g. E. coliTemperature: Bacteria can be : > Psychrophilic: e.g. listeria > Mesophilic: e.g. E. Coli > Thermophilic: e.g. Thermus aquaticus
Temperatures below 15° slow down, freezing temperatures inactivate and above 70° destroy.
Moisture: Requires moisture for growth. Grow best in humid conditions and on food with a high water activity above 0.90aw e.g BreadPh level : Most grow best in slight acidic or neutral environments (ph 6-7).
Extreme acidic or alkaline conditions inhibit bacterial growth.
Time: Require time to grow. In ideal conditions, will double every 20 minutes
Structure of Bacteria
Cell Wall: Gives structure Cytoplasm: contains nuclear material (DNA)
> Ribosomes (allow production of protein)
> Food vacuoles - store foodCapsule : Protective layer that surrounds the cell wallFlagellae:Log thread like structures that assist in movement