Bacteria and Viruses
Microorganisms that cause infectious disease are pathogens.
Bacteria will produce toxins to damage the cell, whilst viruses will attack inside the cell and reproduce.
White blood cells will defend against pathogens by ingesting, producing antibodies to destroy the bacteria/viruses and producing antitoxins to counteract the toxins.
People can be immunised against viruses and bacteria by having dead or weak forms of the pathogen injected into them to stimulate the white blood cells to produce the required antibodies. That way if an active form of the virus enters the body the WBC's will be more prepared to attack the virus.
Antibiotics can treat bacterial infections, but not viruses.
Pathogens can often mutate and become resistant to antibiotics so when all other strains are killed then they are free to reproduce.
Bacteria can only be incubated in school at a max temp. of 25C, but in industry higher temperatures mean more rapid growth