history of microbiology Flashcards
who was the first person to observe and accurately describe bacteria
Antony van Leeuwenhoek (1632-1723)
define spontaneous generation
the belief that living organisms could develop from nonliving matter
who first opposed the theory of spontaneous generation
Francesco Redi
what did francesco redi do to oppose spontaneous generation theory
he did some fun experiments with meat in an uncovered jar, covered, and partially covered (permeable layer)
what were the findings of francesco redi’s experiments
found that maggots only arose in the uncovered and partially covered flasks = they arose from the eggs of flies that were attracted to the meat rather than the meat itself
who came after francesco redi
john needam
what did john needam believe
spontaneous generation could occur under the right conditions
describe john needam’s experiment + findings
had a broth that was heated, then left open as it cooled, he waited, and then observed growth
who came after john needam
lazzaro spallanzani
what did lazzaro spallanzani believe
he believed that the growth from john needam’s experiment was due to the flask being left open (ie experimenter error)
describe lazzaro spallanzani’s experiment
replicated john needam’s (with open flask) and also did it with a closed flask.
open flask= growth, closed flask=no growth
after all the experiments (redi, needam, spallanzani), what did critics have to say
they suggested that heating the air in the sealed flasks destroys the ability of the air to support life
who settled the spontaneous generation controversy
louis pasteur
describe pasteur’s experiment
poured beef broth into a long-necked flask, bent it into an S-shape, boiled it, then observed that there was no growth even though it was exposed to air
summarize pasteur’s findings
microbes are found in nonliving material and they can be destroyed by heat
how is sterility possible
microbes are destroyed by heat, so solutions can be kept sterile by heating them and blocking access of microbes to the solution –> aseptic technique
what is the process of pasteurization
keeping products sterile to make them safe for consumption
what is the germ theory of disease and who came up with it
microbes might be responsible for causing disease; pasteur
what evidence did joseph lister show
microbes could cause disease (but this evidence was indirect)
describe what joseph lister did
he knew that phenol could kill bacteria, so he developed a system of surgery that was designed to prevent microbes from entering wounds (this led patients to have fewer infections)
who came up with the first (direct) proof that microbes could cause human disease
Robert Koch
how did robert koch find the first proof that microbes could cause disease
he was trying to find out what caused anthrax. He took material from diseased animals + injected into healthy ones = mice sick. Using a piece of spleen from a sick mouse, he grew the bacteria in beef serum, injected into healthy mouse = anthrax developed
what was koch’s greatest accomplishment
he found the causative agent of tuberculosis
(it’s a rod-shaped bacterium)
how do we determine if an agent is linked to a disease? (ie what is the name for the steps we follow)
Koch’s postulates
describe koch’s postulates
- microbe must be present in every case of disease and absent from healthy organisms
- suspected microbe must be isolated and grown in pure culture
- same disease must occur when microbe is put into healthy host
- same microbe must be isolated from the now-sick host
