Module 1; pg 4-31
- The study of microbes and how they interact with humans, food, and the environment
- How we (as humans) can take advantage of microbes
- Includes the study of organisms too small to be seen with the naked eye
Microorganism; Includes the bacteria, the microbial eukaryotes, and the archaea
Microbes; Includes microorganisms and viruses
[Viruses are not technically alive]
Note; Microorganism and microbe are terms that are used interchangeably sometimes by scientists, but
these are clearly defined in this course
1.1 What is Microbiology?
- First to use a microscope to identify fruiting structures of mold
o Described fungus growing on leather
o “Molds are actually fruiting bodies!”- If you knock into one, the spores will fall off!
- Discovered microorganisms, but not bacteria or archaea or viruses
Anton(ie) van Leeuwenhoek
- “Father of Microbiology”
- First to see and describe Bacteria
o Plaque from dead old men who didn’t brush their dirty teeth
o Thick biofilm “like batter used to make bread!”
Microorganisms are important!
- Humans eradicated certain diseases
o Ie smallpox, a viral infection
- They make amino acids and vitamins that are vital for human survival!
- Some infect agricultural plants ☹
- Some form plant roots, in order to let the plant grow
o These microbes transform the air’s nitrogen into ammonia that the plants can deal with
▪ These microbes aren’t just for plants! About half of all “fixed” ammonia is due to
microbial fixation 😊
- Degradation of organic matter!
- Used to produce antibiotics, drugs, fermented food products (wine!)…
- Transitioning of chemicals between organic/inorganic, oxidized/reduced forms as part of energy
transfer within the ecosystem Biogeochemistry is catalyzed (largely) by microorganisms
- Ex production of oxygen
o Marine microorganisms undergo photosynthetic processes
o Critical for ozone layer formation
- Use of biological processes or organisms to produce goods or services
- Ex bioreactor uses a population of microorganisms to produce compounds
We study microbiology because we live in a microbial world
• Microorganisms were the first life on Earth.
• Microorganisms created the biosphere that allowed multicellular organisms to evolve.
• Multicellular organisms evolved from microorganisms.
• More than 50% of the biomass on Earth is composed of microorganisms.
• Microorganisms will be on Earth forever.
1.2 About Microbes
Microbial cells consist of macromolecules such as;
- Polypeptides, the building blocks of protein (enzyme = protein)
o Enzymes, a type of protein, is essential for cell biochemical reactions
o Other proteins are structural cell components
o Makes up 50-55% of a microbial cell
- Nucleic acids (Deoxyribonucleotides and ribonucleotides) make up to 25% of the cell
- Lipids and Polysaccharides make up another 20% (10% each) of the cell
- Make DNA or RNA using RNA polymerase
- Glycogen Phosphorylase converts glycogen to glucose monomers
- Motility via flagellin
- Help cell find division plane in binary fission
o Aka the place with lots of FtsZ protein
▪ FtsZ protein catalyzes the breaking/reformation of the cell wall RNA has many purposes
- mRNA encodes for proteins and is involved in translation and transcription
- rRNA is most of the RNA in a cell, and is found in ribosomes
Nucleic Acid- polymer of nucleotides, composed of a sugar, a phosphate, and a nitrogen containing
base that includes DNA and RNA
- mostly found in cell’s lipid bilayer
- has embedded polysaccharides and polypeptides (transporters!)
Polysaccharides, aka sugars, either give structure or are used to store energy
In Chapter 1, the mini-paper “A Focus on the Research: The Three Domains of Life” describes Woese and
his colleagues' seminal paper from 1990: Read it and be able to answer the related Questions for
Carl Woese discovered archaea
Know Table 1.3- difference/similarities between Bacteria, Archaea and Eukarya
- Eukarya has membrane bound organelles
- Archaea’s RNA polymerase is similar to Eukarya, NOT bacteria