Week 1: History of Microbiology Flashcards
During what century were the first microscopes made and the microscopic world discovered?
1600s
Describe the key contributions of Robert Hooke to microbiology.
- constructed compound microscope.
- observed, recorded, and illustrated various organisms.
- published Micrographia coined the term “cells”
Describe the key contributions of Antoni van Leeuwenhoek to microbiology.
- made numerous simple microscopes, over 400
- observed and recorded objects
discovered previously unknown living microbial world
Although Hooke viewed microscopic structures before Leeuwenhoek, the latter tends to be viewed much more favorably. Why do you think this is the case?
Although van Leeuwenhoek was not the inventor of the microscope like Hooke, he advanced it more than anyone else for seeing living things. In his lifetime, his production of quality microscopes introduced mankind to the world of microorganisms.
What feature was Hooke describing when he coined the term cells?
perforated and porous, much like honey-comb.
To what was Leeuwenhoek bringing attention when he coined the now antiquated term animalcules?
Among these were, besides, very many little animalcules, some were round, while others a bit bigger consisted of an oval. And the motion of most of these animalcules in the water was so swift, and so various, upwards, downwards, and round about.
Roughly when did the golden age of microbiology take place?
1800-early 1900s
What were the four key questions that drove great progress during microbiology’s golden age?
- is spontaneous generation of microbial life possible?
- what causes fermentation?
- what causes disease?
- how can we prevent infection and disease?
Dissect the term abiogenesis into its three roots (a-bio-genesis). What do each of them mean?
not- life- to produce, life from nonliving
List three or more observations that made people believe that spontaneous generation occurs.
- mold seemingly grew out of nowhere.
- fly larvae in unrefrigerated food
- bacteria growth
List, in order, the steps of the scientific method.
Hypotheses-> Procedures/experiment->Data/results->Findings/conclusions
Relate Pasteur’s experiment refuting spontaneous generation to the scientific method.
His experiment included a procedure of taking multiple flasks and executing the same process with the exception of a variable he wanted to test. He included a control group.
What is a control group? Why is it important?
- The control group is treated like the experimental groups except it lacks the variable the experiment is testing.
-It’s important because it gives the scientist some time to compare the experimental group to.
In a single sentence, describe the similarities in the experiments of Redi, Needham, Spallanzani, and Pasteur. What were they trying to show and very basically, how did they all attempt to show this?
If you devoid a substance of life and access to the outside world spontaneous growth will occur.
Aristotle in relation to spontaneous generation?
He promoted spontaneous generation.
Francesco Redi
- did study with raw meat, cast doubt on spontaneous generation.
- sealed meat=no maggots, open meat=maggots
John Needham
- infusion experiment, supported spontaneous generation.
- regardless of if sealed with quark, things grew.
Lazzaro Spallanzani
- improved Needham experiment and contradicted his results.
- better sealing of flasks, no growth unless the seal is broken.
Louis Pasteur
- “father of microbiology”
improved Spallanzi experiment, longer boil time and bent neck flask. - made sure to kill everything and better sealed the flask so air can enter but no particles.
- no growth unless neck broken, disproved spontaneous generation.
Was Needham’s experiment on spontaneous generation flawed? Explain.
Needham failed to kill all microbes and or failed to completely seal the vials.
How was Spallanzani’s experiment an improvement over Needham’s?
better sealing of vials then just a cork.
Compare the experimental results and conclusions of Needham and Spallanzani.
They got opposite results. Needham supported spontaneous generation while Spallanzani did not.
Why do you think multiple scientists unable to replicate Pasteur’s results? Does this mean that Pasteur was wrong? Explain.
Per previous scientist experiments, the boiling process needs to be a specific process to kill everything. At the time the importance of that process and how it works was not fully understood so it’s not surprising that it was hard to repeat. Does not mean he was wrong just means the experiment needs to be replicated more.
Describe the process of “tyndallization.” What is its importance to Pasteur’s work on dispelling the idea of spontaneous generation?
process of killing both vegetative and spore microbes. 15 min boiling everyday for 3 days.
What is the modern definition of fermentation?
Partial breakdown of sugars in the absence of oxygen.
How was the term fermentation used differently by scientists in the 1800s?
was used to describe the formation of alcohol, lactic acid, putrefaction of meat and decomposition.
What characteristics of yeast (Saccharomyces cerevisiae) did Pasteur discover through observation and experimentation?
discovered that yeast can grow both in the presence of O2 or without O2.
Faculative Anaerobe
organisms which can survive in both oxygenated as well as the deoxygenated environment
Describe Pasteur’s experiments on fermentation.
introduced yeast to sterilized grape juice in sealed flask. Results in alcohol production. Did the same thing with bacteria and resulted in acid production.
Grape juice sometimes fermented into fine tasting wine, but sometimes yielded an unpleasant acidic liquid. Describe what was happening in each of these cases.
this happens when bacteria contaminates the wine and it spoils. instead of alcohol production, acid is produced.
In a single sentence, briefly describe the process of pasteurization. Of what benefit is this process?
Pasteurization is the process of heating a liquid to the point of killing off bacteria. Kills off bacteria preventing spoilage and disease growth.
For what purpose did Pasteur initially develop the technique of pasteurization?
Avoid wine spoilage.
What did Pasteur show was necessary for fermentation?
Yeast