Microbiology Flashcards
What are postulates?
The 4 standards that must be met in order for a suspected pathogen to be classed as pathogen.
What are Koch’s postulates?
Pathogen must be present in all unhealthy cases.
Pathogen must be grown in pure culture.
Cells from pure culture must cause disease.
Cells must be reisolated and shown to be the same as the original.
What is the nutrient solution that a culture is grown in?
The culture media.
What is a major issue with trying to grow microorganisms in a lab?
Only a tiny fraction of microorganisms can be cultivated in a lab.
What are the 4 types of light microscopy?
Bright-field.
Phase-contrast.
Dark-field.
Fluorescence.
What are the benefits of phase-contrast and dark-field microscopy?
Improved contrast without staining.
What are the 3 ways of imaging cells in 3D?
Differential interface contrast microscopy.
Atomic force microscopy.
Confocal scanning laser microscopy.
Why do we study microorganisms?
Rapid growth rates. Compact. Easy to manipulate. Useful - in industry. Commonalities with other cells.
How does differential interface contrast microscopy work?
Uses polarised light to make cellular structures more three-dimensional.
How does atomic force microscopy work?
Measures forces between a probe and the atoms on the specimen surface.
How does confocal scanning laser microscopy work?
Focuses through the specimen in layers to reconstruct into a 3D image.
Why is it important to understand microorganisms?
They are the causes of many diseases but also have uses in agriculture and biotechnology.
How do you generate a phylogenetic tree? There are 5 stages.
1) Isolate DNA from each organism.
2) Make copies of rRNA gene by PCR.
3) Sequence DNA.
4) Analyse sequence.
5) Generate tree.
What is the largest bacterial phylum?
Proteobacteria.
What were the first oxygenic phototrophs on Earth?
Cyanobacteria.
