Microbiology Exam I- History of microbiology

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.

- Chains of rod-shaped bacteria are found in the blood if disease victims - Injection into mice causes the disease

List at least three environmental roles played by microbial communities.

- Decomposition -Nutrient Cycling -Bioremediation

List three or more observations that made people believe that spontaneous generation occurs.

- Dry lake beds teeming with life after a rain - Appearance of maggots on decaying meat - Appearance of mice from wheat

All scientific theories should have explanatory power. Briefly discuss the observations that are explained by the germ theory of disease.

- Each particular disease is accompanied by the same symptoms in affected individuals - Injection of bacteria into mice causes disease

Prior to the 1800s, what were the various factors thought to be responsible for disease?

- Evil spirits - Astrological signs - Foul vapors - Demon possession - Divine punishment - Imbalances in bodily fluids

Describe the key contributions of Antoni van Leeuwenhoek to microbiology.

- Inventor of simple microscope, which uses one lens - Discovered previously unknown living microbial world which he called "animalcules" - Considered to be first microbiologist

Describe the key contributions of Robert Hooke to microbiology.

- Observed, recorded, and illustrated various organisms using compound microscope (first recorded microscope observation) - Published "Micrographia", in which he coined the term cells

Aside from devising a means by which causative agents of disease can be identified, list a half dozen other important contributions to biology made 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

List at least three different questions that microbiologists are currently working to address.

-How can we develop successful programs to eradicate specific disease? -How can we expand the number of microbes we are able to grow in the laboratory? - How can we reduce the threat posed by drug-resistant microorganisms?

Dissect the term abiogenesis into its three roots (a-bio-genesis). What do each of them mean?

-a: Not/without -bio: life -genesis: Creation (Living organisms created from non-living matter)

What were the four key questions that drove great progress during microbiology's golden age?

1) Is spontaneous generation of microbial life possible? 2) What causes fermentation? 3) What causes disease? 4) How can we prevent infection and disease?

List, in order, the steps of the scientific method.

1) Observations lead to the asking of a question 2) A hypothesis is generated 3) An experiment is conducted to test predictions stemming from this hypothesis 4) The hypothesis is supported or falsified.

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.

1) Observe that milkmaids who had recovered from cowpox rarely got smallpox- why? 2) Cowpox infection gives protection against potentially-fatal smallpox disease. 3) Infected boy with cowpox, and then with smallpox. Boy had become immune. 4) Hypothesis is validated.

Relate Pasteur's experiment refuting spontaneous generation to the scientific method.

1) Observe the growth of life from seemingly nowhere; maggots on rotting meat, mice on wheat left out, etc. 2) All life comes from pre-existing life; spontaneous generation cannot occur. 3) Boil infusions to kill pre-existing life, leave exposed to air but not to dust by creating vials bent into s-shape. Observe vials for life.

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.

1) Production of enzymes/proteins beneficial to humans 2) Infection prevention and treatments 3) Different ways to obtain energy, more efficient/cleaner ways to obtain energy 40 Understanding of genes and development of gene therapies

How was the term fermentation used differently by scientists in the 1800's?

1) formation of alcohol from sugar 2) Formation of lactic acid 3) Putrefaction of meat 4) Decomposition of waste

List Koch's Postulates.

1)The suspected agent must be present in every case of the disease. 2) The agent must be isolated and grown in pure culture. 3) The cultured agent must cause the disease when it is inoculated into a healthy, susceptible experimental host. 4) The same agent must be re-isolated from the diseased experimental host.

During what century were the first microscopes made and the microscopic world discovered

1600's

Why were a number of scientists unable to replicate Pasteur's results? Does this mean that Pasteur was wrong? Explain.

A number of scientists were unable to replicate Pasteur's results because life sometimes arose even after lengthy boiling. This does not mean Pasteur was wrong, instead, it was not known that endospores were heat-resistant and were present in some broths.

Disinfection

A process that eliminates many or all microorganisms, with the exception of bacteria spores, from inanimate objects

Compare and contrast the contributions of the following with respect to spontaneous generation: Aristotle Francesco Redi John Needham Lazzaro Spallanzani Louis Pasteur

Aristotle: Promoted Spontaneous generation, life arose from non-living material if it contained "pneuma" (vital heat) Francesco Redi: Created three flasks with decaying meat; one exposed to the air, another sealed, and another covered with gauze. Maggots did not develop when meat was kept isolated from flies. Cast doubt on validity of spontaneous generation. John Needham: Boiled beef gravy and plant infusions, sealed vials with cork. Found abundant growth days later. Concluded that spontaneous generation HAD occurred. Lazzaro Spallanzani: Boiled beef gravy and plant infusions, sealed necks of vials by melting glass. No growth unless neck of vial was broken. Concludes that Needham's experiment was flawed. Louis Pasteur: Modified Spallanzani's experiment, boiled infusions long enough to kill everything, bent necks into an S-Shape; air could enter but dust could not. Flasks remained void of life for over 18 months. Concluded that spontaneous generations DOES NOT occur.

Reconcile the seemingly different findings of Pasteur and Buchner.

Both Pasteur and Buchner were correct in their findings, but Buchner was more precise in the exact cause of fermentation. Yeast enzymes, known as zymase, are indeed responsible for fermentation, but they are found within yeast cells. Hence, it is indeed possible to separate zymase enzymes from yeast cells and then use the enzyme for fermentation.

Compare the practices of Semmelweis and of Joseph Lister, and how well these practices were accepted.

Both Semmelweis and Joseph Lister were met with negative public feedback. Semmelweis was ridiculed and forced to leave the hospital in which he worked and Lister was initially met with resistance to the use of phenol.

Compare the experimental results and conclusions of Spallanzani and Pasteur.

Both Spallanzani and Pasteur concluded that spontaneous generation did NOT occur. Pasteur modified Spallanzani's experiment by creating vials with necks bent into an S-shape, which still allowed air to enter but not dust. Pasteur was able to apply a "mortal wound" to the concept of spontaneous generation once and for all with his experiment; the idea took time to disprove because it had been such a long-standing idea.

Compare and contrast smallpox and cowpox.

Both smallpox and cowpox cause skin lesions, but smallpox is much deadlier.

Epidemiology

Branch of medical science concerned with the incidence, distribution, and control of diseases that affect large numbers of people.

What did Eduard Buchner show was necessary for fermentation?

Buchner showed that the enzymes of yeast cells were necessary for fermentation.

What term is used to describe the investigation of chemicals that destroy pathogens?

Chemotherapy

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?

Differentiation based upon cell-wall structure (gram + or gram -) are enabled by the procedure of staining. This is helpful in a clinical setting in order to decide what treatments will best eradicate a certain type of bacteria.

What accidental contamination was observed by Alexander Fleming, resulting in the discovery of the antibiotic penicillin?

Fleming observed the accidental contamination of a fungus mold on a plate with bacterial colonies. He observed a lack of bacterial growth near the mold, finding that it secreted a bacteria-killing compound. He named this compound penicillin.

What were the key contributions of Florence Nightingale to the prevention of disease?

Florence Nightingale introduced cleanliness and other antiseptic techniques into nursing practice. She was also the founder of modern nursing.

Did Fracastoro's hypothesis regarding the cause of disease come in the form of a boring old scientific paper? Explain

Fracastoro's hypothesis came in the form of a poem written in Latin and published in three books about the sudden appearance and rapid spread of Syphilis after European travel to the New World.

What did Girolamo Fracastoro propose regarding the cause of disease?

Girolamo Fracastoro proposed that small transferable particles were the cause of disease. He believed these "seeds of disease" are transmitted.

Grape juice sometimes fermented into fine tasting wine, but sometimes yielded an unpleasant acidic liquid. Describe what was happening in each of these cases

Grape juice with the addition of yeast cells became wine because the yeast converts sugars into alcohol and CO2. Bacteria, however, convert glucose, fructose, and sucrose into acids.

Although Hooke viewed microscopic structures before Leeuwenhoek, the latter tends to be viewed much more favorably. Why do you think this is the case?

His simple microscopes were better than the compound microscopes of the time. This allowed Leeuwenhoek to observe single-celled organisms, such as microbes.

Historically, how damaging was smallpox to human populations? To what degree is it a threat to human populations today? Explain.

Historically, smallpox was extremely damaging to human populations, killing an estimated 300-500 million people and responsible for several epidemics over several decades. Fatality rates were generally above 25%. It also devastated Native American populations.

What feature was Hooke describing when he coined the term cells?

Hooke was describing the tiny cells of cork, describing them as "perforated and porous" like a "honeycomb".

Pharmaceutical microbiology

How to manufacture antibiotics, vaccines, and other health products

As we continue to answer scientific questions, are we getting closer to the point where there will be no questions left to ask? Explain.

I do not believe that we will ever reach a point of no questions being left to ask. As more questions are answered, I think even more arise. Additionally, life is constantly changing and adapting. For example, although humans have developed antibiotics, bacteria have also become more and more resistance to these antibiotics. Pathogens always have the capability to adapt and change just as humans develop methods and inventions to solve problems.

Do you think the findings of Ehrlich or of Fleming had the greatest impact on disease prevention? Explain.

I think that the findings of Ehrlich had the greatest impact on disease prevention, while Fleming's findings were more impact on the treatment of diseases. Penicillin is used more to kill bacteria that has already infected a person, while vaccines truly prevent disease by giving the person an immunity. Additionally, although Fleming's findings were extremely impactful, they do have current modern-day ramifications such as antibiotic resistance.

What was the key contribution of Ignaz Semmelweis toward the prevention of disease? How well was this initially accepted in Vienna? In Hungary?

Ignaz Semmelweis mandated that medical students wash their hands with chlorinated lime water. This was not well accepted in Vienna, but it was in Hungary.

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?

It is likely that the infectious agent causing smallpox is closely related to the infectious agent causing cowpox.

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?

It was easier to determine the causative agent of anthrax than to determine the causative agent of tuberculosis because anthrax-causing bacteria are large and easily identified by light-microscopy while tuberculosis-causing bacteria and others are more difficult to distinguish from one another.

Was Jenner's experiment conducted in an ethical manner? Do you think the benefits justified the risks? Explain.

Jenner's experiment was not conducted in an ethical matter. He infected a child who was an orphan with cowpox- exposing him to harm. In retrospect, it is easy to say now that the benefits outweighed the risks because millions of lives were saved and the child survived, but the story would have been completely different if the child died. Jenner could have easily put himself at risk and injected himself with the pathogen instead of a child.

How did John Snow determine how cholera was being spread in London in 1854? What was done in response to his determination in order to reduce the spread of the disease?

John Snow determined that cholera was being spread through a public water supply by mapping the occurrence of cholera during its epidemic in London. In response, the pump handle was taken off of the pump, causing the outbreak to subside.

What culture technique, developed in Koch's lab, was needed before the causative agent of tuberculosis could be identified? Explain.

Koch's technique of isolation of bacteria in the lab using sterile techniques as well as "Koch's Postulates" were needed before the causative agent of tuberculosis could be identified.

To what was Leeuwenhoek bringing attention when he coined the now antiquated term animalcules?

Leeuwenhoek was bringing attention to a previously unknown living microbial world, including bacteria and other microorganisms. He was able to observe their motility through his microscopes.

What is perhaps the most recognized use of pasteurization today?

Likely the pasteurization of milk.

Which of the Kochs has had a net positive impact on the world, the microbiologist or one of the ethically-challenged, union busting promoters of anti-science?

Microbiologist

Many microorganisms are used as model organisms for the investigation of basic biological phenomena. What characteristics make these microorganisms particularly useful as model organisms?

Microorganisms are particularly useful as model organisms because they are 1) Easy to grow, 2) take up little space 3) Are available in large numbers.

Roughly when did the golden age of microbiology take place? (Don't worry about exact start and end dates; these dates are pretty fuzzy anyway. Just get the correct portions of the correct centuries.)

Mid 1800's to early 1900's.

Compare the experimental results and conclusions of Needham and Spallanzani.

Needham observed that his vials contained abundant growth days later, leading him to conclude that spontaneous generation DOES occur. In reality, his experiment was flawed and allowed for contamination of the flasks. Spallanzani modified Needham's experiment by boiling the flasks for longer and protecting the flasks from air/microbes. He did not observe any growths within the flasks, leading him to conclude that spontaneous generation was NOT possible.

Was Needham's experiment on spontaneous generation flawed? Explain.

Needham's experiment on spontaneous generation was indeed flawed. He had not boiled the flasks long enough to kill all microbes. He also left flasks open as they cooled, exposing them to microbial contamination from the air.

Describe Pasteur's experiments on fermentation.

Pasteur first heated flasks of grape juice to kill all microbes. He then introduced yeast cells to some flasks of grape juice , and bacteria to others. He found that those with yeast created wine while those introduced with bacteria became acidic and were responsible for wine spoilage.

What characteristics of yeast (Saccharomyces cerevisiae) did Pasteur discover through observation and experimentation?

Pasteur found that yeast cells only arose from other yeast cells; they were alive. He also found that they were facultative anaerobes.

For what purpose did Pasteur initially develop the technique of pasteurization?

Pasteur initially developed pasteurization in order to kill contaminating bacteria within grape juice, preventing it from becoming spoiled wine.

What did Pasteur propose regarding the cause of disease? What was his basis for this proposition?

Pasteur proposed that microorganisms were the cause of disease based upon his observations that bacteria caused the spoilage of wine.

What did Pasteur show was necessary for fermentation?

Pasteur showed that yeast cells were necessary for fermentation.

Was Pasteur's experiment an improvement over Spallanzani's? Did Pasteur respond to any critics of Spallanzani? Explain.

Pasteur's experiment was indeed an improvement over Spallanzani's; Pasteur boiled the infusions for even longer and bent the necks into an S-shape so that air could enter but dust could not. Pasteur did respond to critics by allowing air to enter in his experiment; he did not destroy the "life-source" that critics had said about Spallanzani's experiment.

In a single sentence, briefly describe the process of pasteurization. Of what benefit is this process?

Pasteurization involves the heating of a product to kill most contaminating bacteria, eliminating pathogens that cause disease.

What was Paul Ehrlich looking for in his magic bullet? To what degree was he successful?

Paul Ehrlich was looking for a magic bullet- a chemical that would destroy pathogen while remaining nontoxic to humans. He did find chemicals effective against pathogens that cause syphilis and sleeping sickness, beginning the field of chemotherapy.

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? (Just one sentence for all of this, and lay off of the semicolons.)

Redi, Needham, Spallanzani, and Pasteur all conducted experiments in which they attempted to prove/disprove spontaneous generation through the use of infusions/non-living matter preserved in flasks which they boiled and sealed and then observed for the growth of organisms after a period of time.

What observations did Semmelweis make regarding deaths to puerpural fever, and how did he explain these observations?

Semmelweis observed that more deaths of puerpural fever occurred in hospital settings versus home-births (20 times more in hospital). He also observed that a doctor who cut his finger during an autopsy died of similar symptoms to Puerpural fever. Explained that medical students carried "autopsy particles" from autopsies into the delivery room.

How was Spallanzani's experiment an improvement over Needham's?

Spallanzani boiled his infusions for longer and sealed the vials by melting the glass instead of using cork.

Why weren't Spallanzani's conclusions immediately accepted?

Spallanzani's conclusions were not immediately accepted because it was difficult to dethrone such a long-standing idea. His critics also said that he did not allow enough air for organisms to thrive and that he had destroyed the "life-force" through prolonged heating.

Briefly state the germ theory of disease.

The Germ Theory of Disease proposes that diseases such as cholera and Tuberculosis are each caused by a specific microorganism. These microorganisms are known as pathogens, and explains why each particular disease is accompanied by the same symptoms in the affected individuals.

What is the modern definition of fermentation?

The partial breakdown of sugars in the absence of Oxygen

What is the primary focus of recombinant DNA technology? List at least two practical applications for this technology. Can you think of any more?

The primary focus of recombinant DNA technology is to isolate, characterize and manipulate genes. Practical applications include the production of human hormones/factors inexpensively, insect resistance in plants/crops, increase yields in food prduction, etc.

Serology

The study of reactions between antibodies and antigens

Molecular biology

The study of the molecular basis of genes and gene expression; molecular genetics.

What is the purpose of Koch's Postulates?

To identify the etiologic agents of disease (which organism specifically causes a disease)

Describe the process of "tyndallization." What is its importance to Pasteur's work on dispelling the idea of spontaneous generation?

Tyndallization is the process of boiling broths for 15 minutes over three consecutive days in order to kill heat-resistant bacteria.

Nightingale's contributions began during the Crimean War. Can you think of any other scientific or technological advances prompted by any other war?

WWI: Poison Gas WWI: Ultrasound

What were the similarities and what was the key difference between the proposals of Fracastoro and Pasteur?

While both Pasteur and Fracastoro both proposed that microscopic particles were responsible for disease, Pasteur made his proposal based on scientific observation while Fracastoro proposed his theory based on little to know actual scientific observation. Additionally, Fracastoro proposed that the disease had been sent as a punishment from the gods upon a man.

Industrial microbiology

branch of microbiology in which microbes are manipulated to manufacture useful products

Environmental microbiology

branch of microbiology studying the role of microorganisms in soils, water, and other habitats

Biochemistry

chemistry dealing with chemical compounds and processes in living plants and animals

Infection Control

practices and procedures that prevent the spread of infection

antispesis

removal of pathogens from living tissue

Immunology

study of the body's resistance to infectious disease

Etiology

study of the cause of disease

Chemotherapy

the use of drugs to treat a disease