B3 Flashcards
What are microorganisms?
tiny organisms: bacteria, viruses, protists and fungi
What’s a pathogen?
A microorganisms that can course disease
What is a communicable disease?
Spread from person to person
How do pathogens spread from person to person? (3)
-Air- droplets from coughing or sneezing
-Contaminated food and water
-Direct contact
How can we stop diseases from spreading?
-Hygiene
-Kill the vectors (e.g. mosquitoes): by spreading insecticides
-Vaccination
-Quarantine/ isolate/ no contact
What are two features of a virus cell?
-cant reproduce by themselves
-10,000 x smaller than animal cells
What do viruses do?
- get inside other organisms cells
- use the other cells own machinery to make loads of copies of themselves
- burst the cell
- releasing lots more viruses
Name three viruses?
Measles
Tobacco mosaic virus
HIV
What does HIV stand for?
Human immunodeficiency virus
What is aids
a disease or syndrome where the persons immune system cant cope any more
What does antiretroviral drugs do?
Prevent the viruses from replicating.
Tobacco Mosaic Virus
-Effects plants: tobacco and tomato plants
-Discolors patches on the leaves: mosaic patter: photosynthesis cant take place in these patches: not enough sugars for growth.
Are viruses made of cells?
No
How viruses spread and multiply?
1) Viruses can pass between humans via the air, contaminated food or water, or by direct contact.
2) As they can’t reproduce themselves, viruses have to enter one of our cells, and then use it to create multiple copies of the virus itself.
3) Once there are lots of copies, the viruses cause the cell to burst, and then go on to infect neighbouring cells.
Symptoms of measels?
Red skin rash
Fever
