Chapter 12 Communicable Diseases

Question 1

What are communicable diseases?

Answer 1

They are caused by infective organisms known as pathogens. They are spread from one organism to another. Vectors can be used to pass the pathogen between organisms.

Question 2

Bacteria pathogens

Answer 2

Bacteria are really small and are in high numbers. However there is a small proportion of the bacteria which are pathogens. Bacteria are prokaryotes

They can be categorised by the following methods:
Shape - rod(bacilli), spherical(cocci), comma(vibrios), spiralled(spirilla), corkscrew(spirochaetes)
Cell walls - The two types of cell walls react differently with gram staining. After gram staining, Gram positive bacteria look purple-blue under a light microscope. Gram negative bacteria appear red. This is because the type of cell wall affects how bacteria react to different antibodies.

Question 3

Viruses Pathogens

Answer 3

Viruses are a strand of genetic material surrounded by a protein. The virus invades the host cell and changes the biochemistry to allow it to replicate and causes the host cell to evolve adaptations to become a successful pathogen. All of the naturally occuring viruses are pathogenic. which means they cause disease in every other type of organism.

Question 4

The viruses that attack bacteria

Answer 4

The viruses that attack and take over bacteria are called bacteriophages. They destroy the bacteria and take over them and use them to replciate.
Bacteriophages are used to identify and treat some diseases, and they are used in scientific research.