Bacteria

Bacteria

1. Categories of Bacteria

   • unlikely to survive in the body
     • conditions of the body is not suitable for it to survive.  unsuitble pH or wrong temperature 
     • if ingested with food usually it will be killed by stomach acid 
   • Desirable Bacteria
     • milk-souring bacteria
       • help in the breakdown of milk in the stomach by renin 
     • in the large intestine
       • contribute to the final formation of faces 
       • some of the intestinal bacteria are dangerous if allowed to multiply on food 
   • undesirable Bacteria
     • Feed on the tissue of the body
     • cause disease by reproducing rapidly in the body and producing poisonous toxins
     • result of
       • unhygienic conditions
       • Direct contact with infected people

2. Bacterial structure

   • single celled
   • single DNA
     • Float freely in the cell
   • slime layer
     • loose gelatinous sheath 
     • deposit around the bacterial cell wall
     • provides protection
     • capsul
       • when the slime layer become thick  it forms capsule
       • for protection 
   • cell wall
     • provide specific shape and protection
     • prevents cell from swelling and bursting due to osmotic changes
     • composed of polysaccharide and protein 
   • flagella
     • extends outward of the cell 
     • long ,slender, thread like structure 
     • help in locomotion 
     • composed of protein flagellin 
     • Directly attached th the plasma membrane and not covered by any sheath 
   • Replication by binary fission

3. Shapes

Imágenes y archivos del mapa