Introduction Flashcards
What are the kingdoms in the 3 kingdom classification?
Bacteria (prokaryote)
Archaea (prokaryote)
Eukarya (includes algae and plants, fungi and animals, and protists)
Where can the largest bacterial cell known be found?
The sea coast of Namibia. We can see it without a microscope
What did Robert Hooke do?
He is the first microscopist to publish a systemic study. Used a compound microscope
What did Antoine van Leeuwenhoek do?
He was the first individual to observe single-cell microbes. He used single-lens magnifiers but did not stain his species. We are not sure if he used dark field microscopy though
Swan neck flak experiment
Boil meat in a flask with a curved neck. Air can freely enter but dust cannot as it gets trapped in the curve. No growth occurred because the dust and germs had been trapped. When the neck was broken microorganisms immediately grew in the broth. Indicated that dust not air carried microorganisms and oxygen does not enable spontanous generation.
What is fermentation caused by?
By living yeast, a single-celled fungus.
No oxygen + yeast = alcohol
No oxygen + yeast + bacteria = acetic acid
What else did Louis Pasteur do besides the swan neck flask experiment?
He was involved in the process of fermentation and was involved with making a vaccine for rabies
What did Rober Koch do?
Identified the causative agent of anthrax, tuberculosis, bubonic plague and malaria
What are Koch’s postulates?
1 - The microbe is found in all cases of the disease but is absent from healthy individuals
2 - The microbe can be isolated from the diseased host and grown in pure culture
3 - When the microbe is introduced into a healthy, susceptible host, the same disorder occurs
4 - The same strain of microbe can be obtained from the newly diseased host
What are some limitations of Koch’s postulates?
- Some microbes that cause disease cannot be isolated and grown in pure culture (e.g. viruses)
- Some diseases are chronic (i.e. the microbe takes several years to develop
- Genetic susceptibility may make certain hosts more prone to developing a disease
What are enrichment cultures?
Enrichment cultures use a selective growth media that supports certain classes of microbial metabolism whilst exluding others.
What is the theory of intracellular endosymbiosis?
Bacteria were engulfed by pre-eukaryotic cells as eukaryotic organelles, resulting in the formation of eukaryotic cells
Why is the intracellular endosymbiosis theory controversial?
It implies a polyphyletic (multiple acentry of living species) species.
What is some proof for the intracellular endosymbiosis theory?
DNA sequence analysis has shown that both the chloroplast and the mitochondria sequences show unmistakable homolgy to those of bacteria . DNA sequencing also shows the simiarity between mitochondria and respiring bacteria and between chloroplasts and cyanobacteria.
How much larger than bacteria are eukaryotes?
10-100x
