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
What did Eduard Buchner show was necessary for fermentation?
Enzymes
What did Eduard Buchner show was necessary for fermentation?
it’s the enzymes in yeast that do all the work. If you can isolate the enzymes you will get the same result as if you used whole yeast. Enzymes are the workhorse of yeast.
Prior to the 1800s, what were the various factors thought to be responsible for disease?
Evil spirits, astrological signs, foul vapors, demons, divine punishment.
In what key way did Ibn Sina contribute to understanding the cause of disease?
proposed diseases can be transmitted through small particles invisible to the naked eye. Argued quarantine to prevent contagion.
What did Girolamo Fracastoro propose regarding the cause of disease?
proposed small transferable particles, studied syphilis.
Did Fracastoro’s hypothesis regarding the cause of disease come in the form of a boring old scientific paper? Explain.
Nope, he wrote a lengthy poem.
What did Pasteur propose regarding the cause of disease? What was his basis for this proposal?
He based his proposal off his wine research in which bacteria cause wine to spoil. Proposed that microorganisms also cause disease. Became known as the “germ theory of disease”.
What were the similarities and what was the key difference between the proposals of Fracastoro and Pasteur?
Both agreed that the particles are very small and transferable. However Fracasoro did not realize the particles are living organisms while Pasteur had that understanding.
Briefly state the germ theory of disease.
Microorganisms are the cause of many diseases. These microorganisms are termed pathogens.
All scientific theories should have explanatory power. Briefly discuss the observations that are explained by the germ theory of disease.
- It explained what diseases share the same symptoms in different individuals, a common source that is the route cause not the individual themselves.
- Contact between individuals transferred the disease and this can be tracked and observed.
Describe the observations and experiments that allowed Robert Koch to demonstrate that a particular rod-shaped bacterium (Bacillus anthracis) was the causative agent of anthrax.
He was able to isolate the bacteria and inject into mice causing the disease.
Why was it easier to determine the causative agent of anthrax than to determine the causative agent of tuberculosis? (What characteristics of these organisms made one easier to identify than the other?)
Size, the anthrax bacteria was larger than the one that causes tuberculosis.
What culture technique, developed in Koch’s lab, was needed before the causative agent of tuberculosis could be identified? Explain.
Culturing on a solid surface, potato or gelatin. Gave the ability to identify individuals’ colonies and inject them into test animals to see what disease each one causes.
List Koch’s postulates.
- found in every case of the disease, absent in health hosts
- isolated and grown in pure culture
- case disease when introduced into healthy host
- same agent isolated from this experimental host.
What is the purpose of Koch’s postulates?
identify specific disease causing organisms.
Aside from devising a means by which causative agents of disease can be identified, list a half dozen other important contributions to biology make in Koch’s lab.
- Use of gel agar
- Koch’s method of isolation
- Simple staining techniques
- Use of petri dishes to hold solid media
-Use of steam to sterilize growth medium
First photomicrograph of bacteria - Transfer of bacteria using a heat-sterilized metal wire
The Gram stain is termed a differential stain. What differentiation is enabled by this procedure, and how might this be helpful in a clinical setting?
some stain purple and others pink, helps differentiate similar looking microbes by something other than shape and size.
What observations did Semmelweis make regarding deaths to puerpural fever, and how did he explain these observations?
he observed that wards with students had higher fatality due to puerperal fever compared to wards without students. Deduced that students were caring the disease with them.
What was the key contribution of Ignaz Semmelweis toward the prevention of disease? How well was this initially accepted in Vienna? In Hungary?
wash your hands! Removing the bacteria through sanitizing your hands stopped the spread of the disease. Vienna did not accept the practice but Hungary readily practiced hand washing.
Compare the practices of Semmelweis and of Joseph Lister, and how well these practices were accepted.
Similar practices. Semmelwise focused on sanitizing the doctors while Lister focused on sanitizing the wounds and space. Both were initially met with resistance.
What were the key contributions of Florence Nightingale to the prevention of disease?
- founder of modern nursing
- set standards for hygiene, requistened scrubbing brushed to clear wards.
- founded the first school for nurses.
How did John Snow determine how cholera was being spread in London in 1854? What was done to reduce the spread of the disease in response to Snow’s determination?
He tracked the spread of the disease and found the common denominator, the water pump. Spread of the disease was reduced by removing use of the pump (took off handle).
Nightingale’s contributions began during the Crimean War. Can you think of any other wars have prompted scientific or technological advances? Explain.
Radar, microwaves, X-rays
Compare and contrast smallpox and cowpox.
both caused skin lesions however cowpox caused mild symptoms and smallpox were deadly.
Edward Jenner noted that milkmaids previously infected with cowpox avoided symptoms of smallpox. Beginning with this observation, describe Jenner’s vaccination experiment in terms of the steps of the scientific method.
observed that milkmaids who had recovered from cowpox rarely got smallpox. Hypothesized that cowpox infection provided protection from smallpox. Tested my infecting a boy with cowpox, which he survived from. Ten infected the boy with smallpox, which he also survived. Conclusion that the previous cowpox infection made the boy immune to smallpox.
Cowpox is caused by vaccinia virus. Given your understanding of Jenner’s experiment and its results, what can you infer about the infectious agent causing smallpox?
Some variation/mutation of the vaccinia virus is little the cause of smallpox.
Historically, how damaging was smallpox to human populations? To what degree is it a threat to human populations today? Explain.
While eradicated since it’s no longer a concern and vaccines are no longer occurring it is a great threat to the human population today. If it was to be release into the public while a vaccine exists the question would be how many would die before the vaccine can be rolled out to the entire population.
What was Paul Ehrlich looking for in his magic bullet? To what degree was he successful?
looking for a treatment to disease (kill pathogens) that was effective but did not harm the host (human). He was semi successful. Chemotherapy, while efficient, is far from nontoxic to humans.
What accidental contamination was observed by Alexander Fleming, resulting in the discovery of the antibiotic penicillin?
contamination by the mold penicillium.
Do you think the findings of Ehrlich or of Fleming had the greatest impact on disease prevention? Explain.
Ehrlich because antibiotics are more widely used and short term has the least amount of side effects to the individual.
Many microorganisms are used as model organisms for the investigation of basic biological phenomena. What characteristics make these microorganisms particularly useful as model organisms?
Easy to grow, take up little space, available in large numbers.
Biochemists seek to develop a deeper understanding of the similarities and differences in the metabolic reactions of microorganisms and other living things. List at least three ways in which such an understanding can be beneficial to humans.
Create pesticides and herbicides that are more targeted and reduce environmental impact.
Better measuring of illness and treatment response.
Treatment of metabolic diseases like diabetes.
What is the primary focus of recombinant DNA technology? List at least two practical application for this technology. Can you think of more?
Manipulation of genes for specific applications. Insulin and Factor VII production via E.coli
List at least three environmental roles played by microbial communities.
Decomposition, nitrogen fixation, carbon fixation, production of vitamins.
What term is used to describe the investigation of chemicals that destroy pathogens?
chemotherapy
List at least three different questions that microbiologists are currently working to address.
- How can we develop successful programs to eradicate specific diseases?
- How can we reduce the threat proposed by drug resistant microorganisms?
- How can we expand the number of microbes we are able to grow in the laboratory?
Antisepsis:
study of substances that stop or slow down the growth of microorganisms.
Biochemistry:
study of chemical and physicochemical processes and substances that occur within living organisms.
Chemotherapy:
investigates the ability of chemicals to destroy pathogenic microorganisms.
Disinfection:
study of eliminating pathogenic microorganisms.
Environmental Microbiology:
study of microbes in their natural habitat.
Epidemiology:
the study of how often diseases occur in different groups of people and why.
Etiology:
study of the causes of disease.
Immunology:
study of the body’s defenses against specific pathogens.
Industrial microbiology:
study of microorganisms used for the production of important substances like antibiotics, food products, and vaccines.
Infection control:
study of the policies and procedures aimed to minimize the spread of infection.
Molecular biology:
studies the composition, structure and interactions of cellular molecules.
Pharmaceutical microbiology:
the study of microorganisms associated with the manufacture of pharmaceuticals.
Serology:
study of chemicals in blood serum that fight disease.
Which of the following statements about anthrax is FALSE?
A) the causative agent of anthrax was identified by Robert Koch
B) anthrax was the first disease shown to be caused by a bacterium
C) anthrax can affect humans as well as various domesticated animals
D)anthrax is caused by a large rod-shaped bacterium
E) all of these statements are TRUE
E) all of theses statements are TRUE
