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Microbiology Cheat Sheet (DRAFT) by

Based on the textbook Brock Biology of Microorganisms.

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Chapter 1: Microbial World

What are the properties of all cells?
Structure, Metabo­lism, Growth, and Evolution
What properties of the cell changes as it gets smaller?
High metabolic rates can be maintained in small prokar­yotic cells without a need for complex cellular struct­ures.
How are viruses different from Bacteria, Archaea, and Eukarya?
Viruses lack a cytopl­asmic membrane and ribosomes. They don’t carry out metabolic processes.
What four bacterial phyla contain the largest number of well-c­har­act­erized species?
Actino­bac­teria, Firmic­utes, Proteo­bac­teria, and Bacter­iodetes
What phylum of Archaea is common worldwide in soils and the oceans?
Thauma­rch­aeota
important contri­buteurs to global nitrogen cycle
How old is Earth and when did cells first appear?
About 4.6 billion yrs old
Cells first appeared 3.8–4.3 billion yrs ago
How do microbes contribute to the nutrition of animals?
Human enzymes lack the ability to break down complex carbs so we rely on our gut microbiome
The “rumen” in ruminant animals (like cows) contains a dense microbiome that digests and ferments cellulose.
Describe ways in which microbes are important in the food and agricu­lture indust­ries.
Agricu­lture benefits from the cycling of nitrogen, sulfur and carbon compounds; which is performed by microbes
While some microbes can cause foodborne disease and spoilage, others are useful for improving food and preser­vation
What is wastewater treatment and why is it important?
It relies on microbes to treat water contam­inated by human waste so it can be safely returned to the enviro­nment.
How did the pasteur flask disprove sponta­neous genera­tion?
The flask had a swan neck that air could enter but not partic­ulate matter including microbes.
The result was that the nutrient solution remained sterile until partic­ulate matter was allowed to enter.
What 2 methods does Pasteur use to make solutions sterile?
1. Porcelain filer to remove cells
2. Heating w/ fire and sealing
What are Koch’s postul­ates?
1. The suspected pathogen must be present in all cases of the disease and absent in healthy animals.
2. The suspected pathogen must be grown in pure culture
3. Cells from pure culture must cause disease in healthy animal
4. Suspected pathogen must be reisolated and shown to be same as original
What color will a gram-n­egative cell be after gram staining by conven­tional method?
Pink
How can cells be made to fluoresce?
They can be stained with a fluore­scent dye, such as DAPI
 

Chapter 2: Structure and Function

What is different about the cytopl­asmic membrane of Archaea?
In the lipids of Bacteria and Eukarya, the hydrop­hobic fatty acid tails are bound to glycerol by ester linkages.
The lipids of Archaea have hydrop­hobic isoprenoid tails which are bound to glycerol by ether bonds.
Functions of the cytopl­asmic membrane
1. Permea­bility
2. Protein anchor
3. Energy conser­vation
What is the periplasm?
It is a space of about 15nm between the outer surface of the cytopl­asmic membrane and the inner surface of the outer membrane.
What are endosp­ores?
Highly differ­ent­iated dormant cells that function as survival structures and can tolerate harsh enviro­nments.
Dormant stage of bacterial life cycle.
How is the outer membrane of an endospore formed?
Engulfment of the foreshore by the mother cell results in formation of the outer membrane.
It is formed from part of the mother cell’s cytopl­asmic membrane.