Module 1: Introduction to Microbiology Flashcards
What are the 3 properties of ALL microbial cells?
- Metabolism - the chemical processes that occur in a living organism (GENETIC [DNA,RNA,Protein] or CATALYTIC [biomolecule synthesis])
- Growth (Binary Fission)
- Evolution (Mutation)
What is microbiology?
The study of microorganisms (microbes) which are lifeforms too small to be seen by the unaided eye
What are the properties of SOME microbial cells?
- Differentiation
- Communication [Biofilm - the assemblage of microbial cells in matrix that communicate to increase likelihood of survival]
- Genetic Exchange [vertical and horizontal transmission]
- Motility [flagellum movement]
What are some fields that involve microorganisms and how do they use them?
- Genetics - engineering vaccines, hormones, etc.
- Agriculture
- Food Science
- Immunology - pathogen-host interactions
- Medicine - plans/measures to cure infectious diseases
- Industry - antibiotics, steroids, vitamins, etc.
Robert Hooke’s Contributions
- Earliest rendition of the light microscope
- Published “Micrographia” in 1665
- First known description of microorganisms
Anton van Leeuwenhoek’s contributions
- Built a more precise, smaller version of Hooke’s microscope
- Discovered bacteria (‘wee animalcules’)
Louis Pasteur’s Contributions
- Founded the “pasteurization” method; a method of eliminating bacteria responsible for spoilage
- Swan neck proved that mixture stayed sterilize for longer after heating and slow cooling versus tilted swan neck
- Sterilization is complete killing of all microorganisms in a mixture
Joseph Lister’s Contributions
- Introduced aseptic techniques for surgeries in 1867
Ignaz Semmel’s Contributions
- Introduced handwashing as a method of preventing infections
Robert Koch’s Contributions
- Wrote Koch’s Postulates
- Discovered that association of bacterium with a certain disease did not equal to cause and effect
- Discovered causative agent for tuberculosis and cholera (Mycobacterium tuberculosis and Vibrio cholerae)
What are Koch’s 4 postulates?
- Suspected pathogen must be present in all samples of infected animal but absent in all samples of healthy animal
- Suspected pathogen must be grown in pure culture (isolate pathogen from tissue)
- Cells from pure culture must cause disease in a healthy animal
- Suspected pathogen must be re-isolated and shown to be same as the original sample
Who are Robert’s Associates and their contributions?
- Walther Hesse: use of agar in growing colonies (his wife?)
- Richard Petri: invention of the transparent double-sided petri dish
Martinus Beijerinck’s contributions
- The Enrichment culture technique
- Isolating of specific types of microorganisms based on metabolic properties
- Chemically defined mediums to isolate rhizobia
- Identified the Mosaic disease in virology
Sergei Winogradsky’s contributions
- Successfuly isolated notable bacteria from natural samples (nitrifying and sulfur bacteria)
–> Clastridium pasterianium and Azotobacter (anaerobic and aerobic nitrogen fixing bacteria) - Chemolithotropy: oxidation of inorganic chemicals for the generation of energy such as the Beggiatoa
How did Frederick Griffith prove that DNA is a basis of hereditary?
- Used Streptococcus pneumoniae
- 4 trials w/ 4 outcomes:
a) Rough strain - alive mouse
b) Smooth strain - dead moiuse
c) Heat-killed SS - alive mouse
d) HKSS + RS - dead mouse - Virulent strain passed molecule to transform rough strain proving DNA is hereditary
4 Advantages of using RNA sequencing
- Universally distributed
- Functionally constant
- Highly conserved (slowly changing)
- Adequate length to provide a deep view of evolutionary relationships
Taxonomy Vs Systematics
Taxonomy refers to naming, nomenclature, classification, identification, morphology
Systematics refers to evolutionary relationships between organisms, via a phylogenetic tree
- Taxonomy is under systematics
2 Early methods of classification
- Ernst Haeckel Tree
–> TREE OF LIFE, depicted evolutionary relationships between organisms via a branching tree - Robert H. Whittaker Tree
–> FIVE KINGDOM CLASSIFICATION, similar to Ernst’s but fungi was separated
5 Steps to discover evolutionary relationships of microorganisms
- Isolate DNA of each organisms
- Make copies of each rRNA gene by Polymerase Chain Reaction
- Sequence DNA
- Analyze DNA sequencing (for similarities)
- Construct Phylogenetic Tree
3 Domains
Eukarya
Bacteria
Archaea
LUCA
Last Universal Common Ancestor
Bacteria & Archaea classifications
Domain
Phylum
Class
Order
Family
Genus
Specie
Endospore Formation
When bacteria sense extreme conditions, they reproduce then store all genetic materials in the septum (eventually forming the spore); when conditions stabilize, spore is ejected to form vegetative bacteria again
4 Phyla of Bacteria
(ABFP)
(Always Bring Four Pokemon)
- Actinobacteria
- Firmicutes
- Proteobacteria
- Bacteroidetes
5 Phyla of Archaea
(TENK C!)
- Thaumarchaeota
- Euryarchaeota
- Nanoarchaeota
- Korarchaeota
- Crenarchaeota
(-aeota)
Characteristics of Viruses
- Not considered living cells
- Only replicate within the cytoplasm of its host cell - obligate parasites
- Cannot conserve energy
- Do not carry out metabolic reactions
- Genomes composed of DNA or RNA that can be either singular or double stranded
- No genes are conserved
- Infect cells of all 3 domains of life
Aseptic Techniques
Collection of practices that allow for the preparation and maintenance of sterile nutrient media and solutions
Sterile
Without presence of living organisms
Pure Cultures
Contains only one type of microorganism
Enrichment Culture Techniques
Isolation from nature of microbes with particular metabolic characteristics
