• Created by: 15howardl
  • Created on: 17-09-21 09:36

Animal and Plant pathogens:

Communicable diseases are caused by infective organisms known as pathogens.

Vector - these carry pathogens from one organism to another, are involved in the spread of a number of important plants and animal diseases.

BACTERIA - There are more bacteria than any type of organism.Bacteria are prokaryotes. They don't have a membrane bound nuclues or organelles.

Bacteria can be classified into two main ways:

  • Their basic shape - rod shaped,spherical, comma, spiralled and corkscrew
  • By their cell wall - the two main types of bacteria cell walls have a different structures and react differently to the process gram staining (gram positive and negative). This is useful because the type of cell wall affects how bacteria reacts to different antibiotics.
  • Examples - Ring rot, Tuberculosis

VIRUSES - They are non-living infectious agents. The basic structure of a virus is some genetic material surrounded by a protein. Viruses invade living cells, where the genetic material of the virus takes over the biochemistry of the host cell to make more viruses. Viruses reproduce rapidly and evolve by developing  adaptation to their host - this makes them very successful. Examples - HIV and influenza and tobacco mosaic virus

Viruses that attack bacteria are known as bacteriophages. They take over the bacterial…


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