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UNIT 3.3 - MICROORGANISMS AND DISEASE - Coggle Diagram
UNIT 3.3 - MICROORGANISMS AND DISEASE
LOUIS PASTEUR
He thought diseases were caused by germs passed on from one person to another.
He was a famous French scientist whose work helped everyone accept the germ theory of disease.
PASTEUR'S HYPOTHESIS
Anthrax is caused by a germ passes from one animal or person to another.
He had an idea - to grow anthrax germs, weaken them and inject them into farm animals.
He wanted to create a vaccine that protected the animals against anthrax.
PASTEUR'S PROBLEMS
He struggled to grow the anthrax germs in his laboratory.
He found it difficult to make a vaccine from them.
Many did not believe germs caused diseases - they challenged Pasteur to prove his theory by a public test.
His lesser-known rival had already made a vaccine using a different method without proving it worked.
PASTEUR'S INVESTIGATION
Step 1: On 5th and 17th May, 1881, he gave 24 healthy sheep, 6 cows, and 1 goat his anthrax vaccine.
A similar group of healthy animals were not given the vaccine.
Step 2: On 31st May, all the animals were infected with anthrax passed on from diseased animals.
PASTEUR'S PREDICTION
He predicted that the vaccinated animals will survive, but the unvaccinated animals will develop anthrax and die
PASTEUR'S OBSERVATIONS
On 2nd June 1881, scientists and members of the public came to see the result.
Just as Pasteur predicted:
All vaccinated animals were alive and healthy.
All the unvaccinated animals were either dead or dying of anthrax.
PASTEUR'S CONCLUSIONS
His experiment showed that the germ theory of disease was correct.
Pasteur changed our view of the world.
He convinced other scientists that infectious diseases are caused by microorganisms, and that we can prevent or cure these diseases by attacking the microorganisms which cause them.
