Biology y8

Digestion: the process of breaking down food stuffs

Ingestion:The process of taking a material into the mouth or the body

Absorption: The physical process of taking small food molecules into an organisms cells

Egestion:The process of expulsion of undigested food material from the digestive tract via the anus as faeces

Enzyme: a chemiacal which helps dissolve food, found in spit, so it can make food soluable.

Micro-organisms- they need sugars, proteins, lipids, water and vitamins and minerals to grow

Bacteria and virus

Bacteria

helpful:

• Makes yeast (bread)
• yogurt
• composting

Harmful

• Causes illness,infection and disease

White blood cells: destroy killer cells

• B-cells release antibodies which neutralise viruses and bacteria
• Some eat bacteria and digest them
• memory cells remember previous diseases and prevent re-infection.

Diseases

• TB
• Tetanus
• MMR
• yellow disease
• Flu