Communicable Diseases Flashcards
What causes communicable diseases?
pathogens such as bacteria, viruses and fungi.
What is the role of a vector and give examples.
They carry pathogens from one organism to another. Common vectors are water and insects.
How are bacteria classified?
By their shape- can be rod/spherical/comma/spiralled/corkscrew shaped.
By their cell walls- Gram positive bacteria appear blue and Gram negative bacteria appear red (when stained).
What is a virus and what is the basic structure of a virus?
They are non-living infectious agents. Structure is some genetic material surrounded by proteins.
How does a virus act as a pathogen?
How are they successful pathogens?
They invade living cells and the genetic makeup of the virus invades the host cell and takes over to be able to produce more viruses.
Successful because they evolve adaptations to the host cell so they survive longer.
What is a bacteriophage?
A virus that attacks bacteria. Some are used to treat diseases.
What are protoctista?
A group of eukaryotic organisms that acts as parasites, using hosts to cause disease.
Give 2 examples of pathogenic protoctista.
hint: they need a vector to work
Malaria and sleeping sickness
Some fungi are saprophytes. What does this mean?
They feed on dead and decaying matter.
Some fungi are parasitic. What does this mean?
They feed on living plants and animals.
Which type, saprophyte or parasitic fungi, cause disease?
Parasitic fungi
What implications does a fungal disease in plants have on a community?
Whole crops can be destroyed therefore causing starvation and a lot of hardship for many people.
Pathogens have two modes of action. What are they?
1) Damaging the host tissue directly
2) Producing toxins which damage the host tissue
Explain how a pathogen works by damaging host tissue directly.
1) Viruses- take over the DNA of host cell, makes new viruses, these burst out and destroy the cell.
2) Protoctista- digest and use host cell contents to reproduce, then break open the host cell.
3) Fungi- digest living cells and destroy them.
Explain how a pathogen produces toxins to damage tissue of a host cell.
1) Bacteria- produce toxins that poison or damage the host cell in some way.
2) Fungi- produce toxins that damage the host cell.
