Infection and response 1 Flashcards
Types of Disease
What is a pathogen?
A microorganism that causes infectious disease.
What is a communicable disease?
A disease that can be transmitted from one organism to another because it is caused by a microorganism.
How are pathogens spread?
-Direct contact (contaminated surfaces)
-Air (inhalation of airborne droplets)
-Water (contaminated water e.g.cholera)
Name 4 different pathogens
-Bacteria
-Virus
-Protist
-Fungi
What do pathogens do?
-Depend on their host to provide the conditions and nutrients that they need to grow and reproduce
-Make us feel ill
What are viruses?
-not cells
-not living
-still considered organisms
-10000x smaller than animal cells
How do viruses make you unwell?
They reproduce rapidly inside host cells by using the cells’ machinery to produce many copies of themselves.
This causes damage to the host cell, and the cell will usually burst after a time, releasing the viruses which colonise another cell.
It is the cell damage that makes you feel ill
Example of viral diseases
-Measles
-HIV
-TMV
How is measles spread?
Inhalation of airborne droplets (when an infected person coughs or sneezes)
Measles symptoms
-Red-skin rash
-Fever
-(In serious cases pneumonia, blindness, death=why most young children are vaccinated against it)
How can we prevent the spread of measles?
-Vaccination
-Isolate the infected
How is HIV spread?
-Direct sexual contact
-Exchange of bodily fluids e.g. blood when sharing needles
What does HIV stand for?
Human immunodeficiency virus
HIV symptoms
-Mild, flu-like
-Until it develops into late stage HIV, or ‘AIDS
What is AIDS?
A viral infection where the immune system is so weak that the body can no longer fight infection.
What are people with AIDS prone to?
Catching unusual infections
How can we prevent HIV developing into AIDS?
Regular use of antiretroviral drugs, which prevent viruses replicating.
What are bacteria?
-Very small, prokaryotic cells
-Can reproduce rapidly inside your body
Examples of bacterial diseases
-Salmonella
-Gonorrhoea
What does TMV stand for?
Tobacco mosaic virus
What does TMV affect?
It is a widespread plant pathogen affecting many species of plant, e.g. tomatoes.
How is TMV spread?
Direct contact between diseased and healthy plants
(can stay in soil for up to 50 years)