Chapter 1 – An Invisible World Flashcards
Define: Microorganisms/Microbes
Very small organisms, many types of microbes are to small to see without a microscope, although some parasites and fungi are visible to the naked eye.
What was Thucydides contribution to microbiology?
He observed that survivors of the Athenian plague were not re-infected—showing and understanding of immunity.
Marcus Terentius Varro proposed…
things we cannot see (microbes) can cause disease.
Accomplishment of Antonie van Leeuwenhoek in microbiology
First to develop a lens powerful enough to view microbes (“animalcules”).
Accomplishments of Louis Pasteur in microbiology
- fermentation caused by microbes
- invented pasteurization
- created a rabies vaccine
- swan neck flask experiments disproving spontaneous generation theory
- discovered enantiomers (mirror images of chiral molecules) via optical rotation experiments.
Accomplishments of Robert Koch in microbiology
- identified the microbes that cause anthrax, cholera, and tuberculosis.
- developed solid media, Petri dish, steam sterilization
- “Postulates” to confirm the infectious nature of diseases
Explain Robert Koch’s postulates
1) The same microbe are present in every case of the disease.
2) The microbes are isolated from the tissues of a dead animals, and a pure culture is prepared.
3) Microbes from the pure culture are inoculated into a healthy, susceptible animal. The disease is reproduced.
4) The identical microbes are isolated and recultivated form the tissue specimens of the experimental animal.
Define taxonomy
The classification, description, identification, and naming of living organisms.
Describe Linnaeus’s taxonomy
three kingdoms- animal, plant, and mineral (later abandoned mineral kingdom). In animal and plant kingdoms grouped organisms by kingdom, class, order, family, genus, and species.
Define Phylogenies
taxonomies that took into account the evolutionary relationships of all different species of organisms on earth. depicted by a phylogenetic tree (tree of life)
Who proposed the kingdom Protista for unicellular organisms?
Ernst Haeckel
Who proposed the kingdom of Monera for unicellular organisms whose cells lack nuclei?
Ernst Haeckel
Who proposed the fungi kingdom?
Robert Whittaker
Who categorized the kingdoms into super kingdoms (eukaryotes and prokaryotes)?
Robert Whittaker
Who organized the phylogenetic tree into domains(Bacteria, Achaea, Eukarya)?
Carl Woese and George Fox
What are the current domains of the phylogenetic tree?
Eubacteria, Archaebacteria, Eucaryotes
How were the modern domains of the phylogenetic tree categorized?
16S rRNA sequencing divided the organisms into domains all coming from a common ancestor.
Define binomial nomenclature
a two-word naming system for identifying organisms by genus and species
What is the proper format of binomial nomenclature?
(all italicized) Genus species
What is the range of light microscope?
greater than or equal to 100 nm
What is the range of an electron microscope?
0.5 nm - 1 um
What is the typical size of bacteria
~1-2 um
What is the typical size of yeast?
~3-4 um
What is the size range of viruses
~10 nm - 500 nm (very few that large)
What is the size range of a protein?
~5 nm - 10 nm
acellular
not composed of cells
examples of acellular microbes
viruses, prions
Bacteria
prokaryotic organisms that usually have peptidoglycan cell walls
bacillus
rod-shaped
Coccus
spherical
coccobacillus
ovular
vibro
curved rod
spirillum
loose spiral
spirochete
tight helical spiral
Archaea
unicellular prokaryotes that live everywhere including extreme environments, do not contain a peptidoglycan cell wall , commonly have cell walls composed of pseudopeptidogylcan,
list the types of eukaryotic organisms
protists, fungi, plant, animals
Define protists
unicellular eukaryotes that are not plants animals or fungi (e.g. algae and protozoa.
Algae
plant like protists that are unicellular or multicellular with cellulose cell wall, they are photosynthetic
Protozoa
- protists important in many food webs
- can be parasites
- can be photosynthetic
- use cellular structures to move like pseudopod, flagella or cilia.
- absorb or ingest organic chemicals
Fungi
- unicellular (yeast) or multicellular (ex. mushrooms, molds)
- cell walls made of chitin
- not photosynthetic
- use organic chemicals for energy
Helminths
parasitic worms with microscopic eggs and larva (e.g. tapeworms, guinea worms)
Viruses
- acellular microbes
- contain proteins and genetic material (DNA or RNA not both)
- require a host to replicate
- core is surrounded by a protein coat
- coat may be enclosed in a lipid envelope.
list beneficial used of microbes for humans
disease prevention, food (fermentation), pharmaceuticals, environment (nitrogen fixation), and agriculture
how long have microbes been known to survive?
yeast- up to 45 million years
bacteria- up to 250 million years
What cellular machinery does it take to build a gram negative bacterial cell?
Genomic DNA, Ribosomes, Peptidoglycan cell wall, RNA polymerase, DNA polymerase, Flagella, Cytoplasmic membrane, LPS membrane
What is the function of the LPS membrane?
lipopolysaccharide membrane contributes to the structure of the cell and it also protects the cell from the outside environment.
What is the function of Genomic DNA?
contains the genetic material of the organism which is required for the cell’s function and replication.
What is the function of a ribosome?
Ribosomes synthesize proteins from mRNAs using tRNAs
What is the function of the peptidoglycan cell wall?
provides significant structure to the cell.
What is the function of RNA polymerase?
synthesizes the different types of RNA from the genomic DNA.
What is the function of DNA polymerase?
synthesizes new DNA for cell replication form ht e existing genomic DNA.
What is the function of the flagella?
tail-like structures that are used to move the cell in its environment.
What is the function of the cytoplasmic membrane?
is a selective permeability barrier and also provides some structure for the cell.
What are viroids?
smallest particle able to replicate, made of short single stranded RNA with no capsid, causes disease in plants.
Prions
misshapen proteins that cause neurodegenerative diseases by converting all of the healthy protein to the misshapen one creating holes in the brain.
Bacterial Endospores
can only be made by some gram positive bacteria and is a response to stressor in the environment to ensure that the survival of the bacteria.
Autotrophic bacteria
CO2 fixing bacteria
Heterotrophic bacteria
need organic nutrient source
Phototrophic bacteria
can use light as an energy source
chemotrophic bacteria
performs chemical reactions to create energy (e.g. sulfur reducing bacteria)
Normal human microbiota
the microbes present in and on healthy humans
- prevents growth of pathogens
- produce growth factors, folic acid and vitamin K
Biofilms
- microbes attach to solid surfaces and grow into masses
- will grow on rocks, pipes, teeth, and medical implants.
Emerging infectious diseases (EIDs)
new diseases and diseases increasing in incidence
