Early years of microbiology Flashcards
Antoni Van Leeuwenhoek
(17-18th century)
-developed simple microscope, examined water to see tiny animals, fungi, algae, and single celled protozoa
-was a single lens microscope he made it because he was a tailor and glass maker
-called them “animalcules/ beasties” but eventually called microorganisms which were grouped into Bacteria, Archaea, Fungi, Protozoa, Algae and small multicellular animals
Carolus Linnaeus
(1707-1778)
-developed a system for naming plants and animals and grouping similar organisms together (taxonomic system) into plants or animals
Bacteria and Archaea
-all are unicellular, lack a true nucleus and they’re usually much smaller than eukaryotes
-are found everywhere there is sufficient moisture, even in extreme environments
-reproduce asexually only
-In bacteria their cell walls contain peptidoglycan but a few lack cell walls
-most bacteria do not cause diseases, but are beneficial
-archaea usually have cell walls but are composed of polymers other than peptidoglycan
-no archaea known to cause disease
Fungi
-are eukaryotic organisms
-they obtain food from other organisms which means they are classified as heterotrophs
-always have cell walls
-mold, yeast, mushrooms, morels, toadstools are a type of fungi
Mold
-multicellular, have hyphae (filamentous growth) reproduce by sexual and asexual spores
-would rather produce sexually because opportunity, conditions and provide diversity
Yeast
-unicellular, reproduce asexually by budding some produce sexual spores via conjugation
Protozoa
-single celled eukaryotes usually heterotrophic
-similar to animal cells in nutritional needs and structure
-live in water but some live inside animal host as parasites
-most reproduce asexually, some sexually (paramecium)
-most are capable of motility/locomotion by cilia, flagellum, pseudopodia
-exceptions are apicomplexans which lack motility
Algae
-unicellular or multicellular
-all are photosynthetic (classified as autotrophs)
-they have relatively simple reproductive structures and some can reproduce sexually or asexually
-categorized/classified on their pigmentation, storage products, cell wall composition
Photosynthesis
-organism use light, water, and carbon to create oxygen and energy in the form of sugar
Parasitic worms
-range in size from microscopic to adult (10 m)
-scientists diagnosis infections by looking at the eggs underneath a microscope
Viruses
-hid from Leeuwenhoek b/c of size not visible unless using an electron microscope
-they are acellular (not composed of cells) they have genetic info (DNA/RNA) surrounded by protein coat
Bacteriophage
-meaning to eat bacteria
-it destroys bacteria and uses it as nutrients to make more copies of itself
Abiogenesis
-spontaneous generation
Aristotle
(384-322 B.C)
-proposed abiogenesis to explain why life force was apparent
-during the golden age (1850-1900)
-we could not see the elements but knew all we needed is water
Francesco Redi
(1626-1697)
-was against abiogenesis and wanted to prove that
-had a series of experiments showing decaying meat
sealed: no flies or maggots appeared
exposed: maggots appear and flies
covered: flies could not get in but maggots appeared on the cheese cloth
** proved animals do not spontaneously generate
John Needham
(1713-1781)
*believed in abiogenesis
-boiled beef broth and plant infusions for a short period of time, saw vial was still cloudy with a host of microbes
** he explained he killed everything so there must be a life force
Golden age generated four questions
- How does fermentation occur
- How to prevent disease and infection
3.is spontaneous generation of life possible
4.what causes diseases
Lazzaro Spalllanzani
(1729-1799)
- disproved abiogenesis
-he boiled infusions for an hour and melted the neck of the bottle to seal it shut
-liquid stayed clear so he concluded
1. needham did not boil his infusions long enough or did not seal if properly
2. microorganisms in the air can containment your experiment
3. spontaneous generation does not occur, need living things
**critics said his sealed vials did not allow enough air, and heating prolonged destroyed life force
Louis Pasteur
(1822-1895)
-against abiogenesis
-he boiled infusions long enough to kill everything but he used an s-shaped neck bottle to allow air in but not the dust and microbes
-he concluded no microbes grew after 18 months, he even had nutrient rich broth
-he let the contents in the flask touch the dust sitting in the neck of the bottle, then microbes grew
**microbes were progeny found on the dust in the air
Scientific method
debate led to this method
1) observe a phenomenon
2) generate a hypothesis
3) Design and conduct and experiment to test hypothesis
4) based on observation, accept, reject, modify