B1.1.2 ~ Disease Flashcards
What is bacteria?
Bacteria are single celled living organisms which are smaller than animal or plant cells so you need a microscope to see them.
What are pathogens?
Pathogens are microorganisms which cause disease. The most common pathogens are bacteria and viruses.
What is a virus?
Viruses are much smaller than bacteria. Cannot be seen under normal microscopes, viruses are usually regular in shape.
How do pathogens cause disease?
Once bacteria & viruses get into the body they reproduce due to suitable temperature.
How do bacteria cause disease?
Split in two and produce toxins. Bacteria can damage cells in your body causing disease, toxins can make the person unwell.
How do viruses cause disease?
They take over your body cells and reproduce inside them and destroy the body cell. This makes a person unwell.
How do diseases spread?
Droplet infection
Direct contact
Contaminated food/drink
Break In skin/punctures
How does the body defend itself against disease?
Mucus membranes in breathing system produce mucus to trap pathogens.
The skin acts as a barrier preventing pathogens entering.
Platelets in blood seal cuts In skin forming scabs.
White blood cells produce phagocytes which engulfs & digests the pathogens.
White blood cells produce lymphocytes which produce antibodies and antitoxins.
Whats an antigen?
It’s a protein on the surface of each bacteria/virus. Different bacteria/virus have different antigens.
Whats an antibody?
It’s a protein produced by white blood cells that attach to antigens. Each antibody is specific to a particular disease.
What are antitoxins?
Chemicals produces to neutralise the toxins produced by the pathogen.
How do vaccinations work?
1) person is given a dead or modified form of pathogen.
2) this stimulates the antigens on the pathogen.
3) the production of antibodies by white blood cells.
4) antibodies kill pathogens.
5) memory cells remember how to make antibodies if exposed to real like pathogen.
Why do antibiotics not destroy viruses?
Antibiotics move through the blood but doesn’t go into the cell where the virus is therefore doesn’t destroy it. It’s very difficult to develop drugs that destroy viruses without damaging the cell itself.
Pros of vaccinations?
1) vaccines have helped control & eradicate lots of infectious diseases.
2) epidemics can be prevented if a large percent of population is vaccinated. This means fewer people are likely to catch disease and then pass it on.
Cons of vaccinations?
1) don’t always work, sometimes don’t give you immunity.
2) some people have a reaction to the vaccine e.g fever, seizures etc.
