What is microbiology- Lecture 1 Flashcards
What is microbiology?
study of things that cannot be seen with the unaided eye
What are some examples of microorganisms?
Viruses
Bacteria
Yeasts
Protists (protozoa)
Micro Algae
What are not microorganisms?
Fungi
Helminths
who was Antonie Van Leeuwenhoek?
In the 1680s he discovered both protists, bacteria and yeast with the first microscope at 50-300X magnification
Where do microbes thrive in?
Water, soil and animal bodies
What 2 ways can microbes come from?
- Spontaneous generation
- Arise from pre-existing organisms
What was spontaneous generation?
It was the earliest theory to do with “vital forces in the air” and was “proved” in experiments but was technically poor
How do microbes come from pre-existing organisms?
This was proved by Louis Pasteur in the 1800’s and was done by swan necked flasks and microbes on dust particles in the air
What are swan necks
narrow pipes that slow air flow. Slowed air flow can’t carry particles and this means the airborne microbes behave as particles
Who was Robert Koch?
In 1905 he did a study of Anthrax in cattle. The cattle had bacteria in their blood
(Bacillus anthracis). He grew the bacteria in laboratory (isolated them) and showed that they could pass the disease on to healthy cattle.
what were the 3 implications of the swan neck flask experiment?
- After Pasteur, widely accepted that decay is microbial and can spread easily.
- In Pasteur’s time infectious diseases were the major killers of man.
- Infectious diseases were known to spread easily, and it was possible that this property was due to a microbial aetiology
What were the main findings from Koch’s experiments?
- The microorganism is present in all cases of the disease.
- The microorganism is absent from healthy individuals.
- The microorganism can be isolated and grown in pure culture.
- The isolated microorganism can be reintroduced into a healthy host where it can cause disease.
- The same microorganism can be reisolated from the experimentally infected host.
For a liquid growth media to be grown, what is needed?
Bacteria + nutrients (broth) = growth
what changes the appearance of the broth?
Growth
What turns a broth cloudy (turbid)?
High numbers of cells and this makes it difficult to determine the composition of the bacterial population
Is a turbid broth culture composed of a single bacterial species or a mixture of species?
It can be from either
what is agar not?
a nutrient
What allows solid growth media to grow?
Bacteria + nutrients + solidifying agent = growth
what is agar?
a polysaccharide isolated from seaweed that is a liquid at 100oC and solid at 45oC
very difficult to digest for human/animal pathogens
Most widely used solidifying agent