1)Can be good and bad microorganisms. Most cause no harm, PATHOGENS are harmfull and cause disease and if succesful cause infection.
To be classed as a Pathogen it must: Gain entry to the host, colonise the tissues of the host, resist the deffences of the host, cause damage to the host tissues.
Bacteria,virus and fungi are Pathogens.
A disease occurs when we see symptoms. Passes on =Transmission
2) Microoranisms gaining entry
Pathogens get in by penetrating organisms interfaces ( e.g.skin- effective as it is think, continuous layer)
Some interfaces have evolved to allow…