Chapter 1 - The Microbial World and You Flashcards
Microorganisms (aka microbes)
-minute living things that are too small to be seen with the unaided eye
-includes bacteria, fungi (yeasts and molds), protozoa, algae, viruses
Micro
“very small”
Organism
“living thing”
Photosynthesis
-some microbes play a role in this and contribute to oxygen generation
Nomenclature
-many of the names of microorganisms are latinized
-microorganism name consists of two words with the first word always capitalized
-these names are universal
-both names are underlined or italicized
-abbreviated versions (after being mentioned once) has initial of genus followed by specific epithet ie. E. coli
Genus name
-the first name
-always capitalized
Specific epithet
-second name
-always lower case
(M)icro
Microscopic
m(I)cro
Independent units
mi(C)ro
Complex (less complex than humans)
mic(R)o
Rapid growth
micr(O)
Omnipresent (common/widespread)
Why do we learn about microorganisms?
-to prevent disease occurrence
-develop aseptic techniques to prevent spread of disease
-to prevent food spoilage
Kingdoms
-microorganisms are divided into two kingdoms: Prokaryotes and Eukaryotes
Prokaryote
-lack a nucleus and other organelles
-have one circular chromosome of DNA (a free floating Nucleoid)
-have only ribosomes (smaller than in humans)
-have a complex cell wall made of peptidoglycan
-cell divides via Binary Fission
Binary Fission
-a type of asexual reproduction that involves the separation of the parent cell into two daughter cells
Eubacteria
-simple, unicellular organisms
-are prokaryotes
-appear in Bacillus, coccus, and spiral shapes
-many can swim using flagella
-are usually disease causing
-have quorum sensing ability
Quorum Sensing
-the regulation of gene expression in response to fluctuations in cell-population density
Archaea Bacteria
-prokaryotic bacteria
-if they have cell walls, the wall does not contain peptidoglycan instead it has pseudopeptidogylcan
-not known to cause disease in humans
-live in extreme environments
Eukaryote
-have a true nucleus
-DNA consists of several chromosomes surrounded by nuclear membrane
-contains several organelles such as RER, SER, ribosomes, etc.
-don’t have a cell wall
-somatic cells go through mitosis
-gametes undergo meiosis
Fungi
-eukaryotes
-may be unicellular (yeast/mold) or multicellular (mushrooms)
-don’t carry out photosynthesis
-cell wall composed of chitin
-reproduce sexually or asexually
Protozoa
-unicellular eukaryotic microbes
-move via pseudopods, flagella, or cilia
-live as free entities or parasites
-some photosynthesize ie. Euglena
-reproduce sexually or asexually
Algae
-photosynthetic
-eukaryotic
-reproduce sexually and asexually
-cell walls are made of cellulose
-usually unicellular
Parasites
-eukaryotic
-animal parasites
Humans
-are eukaryotic
Viruses
-acellular (are not cells)
-neither prokaryote or eukaryote
-need electron microscope to see
-reproduce using cell machinery of other organisms
-only considered living when they multiply within host cells they infect
-ie. HIV, Measles, Herpes, Hepatits, Covid-19, Influenza
Covid-19
-continues to mutate (ie. delta, omicron, 3N1)
-coronavirus
-has spikes
-a mutation of SARS-CoV2
-MERS-CoV2 is transmitted between animals and people
Pandemic
-widespread occurrence of a disease over the whole world or a country at a particular time
Epidemic
Widespread disease within a community at a particular time
Cell Theory
-developed by Robert Hooke (1665)
-all living things are composed of cells
Spontaneous Generation
-the belief that life can arise spontaneously form non-living matter
Louis Pasteur (1822-1895)
-disproved Spontaneous Generation in 1861
-proved Biogenesis
-looked at food spoilage (beer/wine)
Biogenesis
-Pasteur demonstrated that microbes are present in the air and can contaminate sterile solutions but air doesn’t create microbes
Pasteurs Biogenesis Expiriement
1) Open flask: found microbes entered the open flask
2) Closed flask: found microbes did not enter the flask
3) S-neck flask: found microbes couldn’t enter the contents, even though air could get it, the curved neck trapped microorganisms
Aseptic Techniques
-formed from the foundation of Biogenesis
-procedures that prevent contamination of unwanted microorganisms
Fermentation
-many scientists believed air converted sugars into alcohol in the absence of air
-Pasteur found that instead yeasts converted the sugars into alcohol in the absence of air
Souring and Spoilage
-caused by bacteria which is then converts sugar into alcohol and then eventually acetic acid (vinegar)
Pasteurization
-Pasteurs solution to food spoilage
-applying just enough heat to kill the bacteria that caused the spoilage
Robert Koch (1843-1910)
-established steps to link a specific microbe to a specific disease (Germ Theory of Disease)
-discovered Bacillus anthracis caused Anthrax
Anthrax
-a biological weapon (used on 9/11) that causes death
Koch’s Postulates
-experimental steps to prove that a specific microbe causes a specific disease
Edward Jenner (1749-1823)
-found a way to protect people from small pox
-used fluid from a small pox blister and injected it into his son
-found his son was protected from small pox
Immunity
protection from disease via vaccination
Immunization
-Pasteur came across Jenner’s work and called it immunization
-the term vaccination was derived from vaca which means “cow”
