2.3 Communicable Disease 2 - Viruses Flashcards
If viruses cant reproduce by themselves, how do they spread?
One they get inside another organism’s cell, they use that cells own machinery to make loads of copies of themself. When the time is right, they can burst the cell. This process of colonising and bursting our cells will damage our bodies - this is why they make us feel ill
What are 3 examples of viruses?
- HIV
- Measles
- Tobacco mosaic virus
How is the measles virus spread?
It is spread by droplets when an infected person coughs or sneezes
What are the symptoms of the measles virus? (2)
- Red rash across body
- Fever
How can HIV be spread? (2)
- By sexual contact
- Exchanging body fluids (sharing needles)
What does HIV stand for?
Human Immunodeficiency virus
What are the symptoms of HIV?
It causes flu-like symptoms (fever, tiredness, aches) for a few weeks, but after that the person doesn’t usually experience any symptoms for several years.
After a person infected with HIV has the initial symptoms, what happens next?
The virus enters the lymph nodes and attacks the immune cells. If the immune system isn’t working properly, it cant cope with other infections or cancers.
At this point, the virus is known as AIDS
What is the medication that can get rid of HIV
Antiretroviral drugs, they prevent virus replicating and if people have access to these in the early stage of their disease, they can live normal lives
Give two examples of plants that can be affected by TMV
- Tobacco
- Tomato
What happens to the plants when TMV infects them?
- It causes the leaves to become mottled and discoloured, causing a ‘mosaic’ pattern to form
- Photosynthesis cant take place and so overall the plant wont be able to produce enough sugars for growth
How is TMV spread?
It’s spread when infected leaves rub against healthy leaves
