Ch 1 Flashcards
Antoni van Leeuwenhoek (1632-1723)
Dutch fabric merchant, began making simple microscopes. Not the first to invent microscopes, but first to look at living samples. Discovered “wee animalcules” aka microorganisms and came up with 5 categories. Biggest contribution: royal society of London.
What were the five categories of microorganism described by Leeuwenhoek and what didn’t he find and why?
Included prokaryotes, small animals, fungi, algae, and Protozoa. He couldn’t see viruses because he used a light microscope which they were too small to see with.
Carolus Linnaeus (1707-1778)
Swedish botanist, develop system of taxonomy (grouping things together based on similarities). genus and specific epithet=binomial naming system uses two names of general and specific of Latin origin.
What are the three domains of life?
Bacteria (prokaryotes) , Archaea (prokaryotes) and Eukarya(eukaryotes).
Acellular microbes and why are they not a part of the three domains?
Viruses, virions , and prions. Not part of the domains because they aren’t alive.
What four questions were scientists trying to answer during the “Golden Age” of Microbiology?
- Is spontaneous generation of life possible?
- What causes fermentation?
- What causes diseases?
- How can we prevent infections/diseases?
What is spontaneous generation? (A-biogenesis)
Getting life from nonliving material.
Who first proposed the idea of spontaneous generation and where did they believe that life came from?
Aristotle.
He thought H2O and soil created life
Ex. Nile river dry out = no life vs water in river = frogs
Who first doubted spontaneous generation?
Francesco Redi
Francesco redi experiment 1 (late 1660)
Doubted spontaneous generation, tested this by putting meat in a jar and sealed out air to prove that flies came from other flies, and not from the meat and air. People complained that he was excluding air and he needed to include air to truly test it.
Francesco Redi experiment 2
(What he did and his conclusion)
During the second experiment, Redi covered the meat with gauze, and observed flies, dropping eggs on top, but they never got in. His conclusion- for larger animals life comes from life (biogenesis).
John Tuberville Needham (1740s)
Boiled meat and plants for short amount of time and kept the jar closed with a cork, which resulted in spontaneous generation of microbes. People wondered, whether or not the cork was actually considered sterile.
Lazaro Spallanzani (1799)
Copied needham’s experiment, but instead fused the glass closed and boiled the beef and plants for a longer period of time. Results - no growth, meaning that he came to the conclusion that spontaneous generation does not happen with microbes.
Why did Spallanzi believe that needhams experiment conclusion was wrong?
He didn’t boil the water long enough, used a cork instead of sealing flask, and that abiogenesis doesn’t occur for microbes.
What did critics say was wrong with Spallanzani’s experiment?
Since he sealed his flask closed, it meant that there was no air which means no growth and that the prolonged heat killed the “life force.”
Louis Pasteur (1822-1895)
Settled the debate by using a swan-neck flask, which allowed for steam/air to move in and out of flask as it was boiling, but prevented dust from getting inside, as it would rest on the bend. Conclusion- biogenesis.
What is the scientific method?
Observation, followed by questions in order to generate a hypothesis. In order to test hypothesis, experiment is then created and observed. Then the hypothesis is either accepted, rejected or modified and tested again.
What’s the difference between a hypothesis and a theory?
A hypothesis is an assumption (educated guess) made before research and can be tested in order to prove it correct/incorrect where as a theory has already been tested and has data to back it.
What causes/is fermentation?
sugars being broken down by enzymes of microorganisms in the absence of oxygen. Conversion of sugar into alcohol.
Ex. Yeast
What were the different beliefs of how fermentation worked?
Air caused fermentation due to its life force, spontaneous generation of yeast/bacteria, yeast causes fermentation, and bacteria causes fermentation
What did Louis Pasteur discover when testing different theories people had about fermentation?
He tested these different theories and these were his results.
Air - no ferm, no microbe
Bacteria - juice become sour acidic and vinegar-like
Yeast - alcohol is produced =wine!
Pasteurization
Heating a liquid to kill some microbes
Pasteur was known as…
Father of microbiology
Define etiology
Study of the cause of disease
What were the prevailing theories of what caused disease?
Bad air, sin, and evil spirits.
Germ theory
Proposed by Pasteur, he believed that microorganisms were responsible for disease. This was due to the fact that particular diseases have specific symptoms and is caused by a specific organism (pathogen).
Robert Koch (Germany, 1843-1910)
Studied numerous diseases and was first to discover a pathogen. He identified the causation agent of anthrax and discovered the cause of tuberculosis. He developed rules for identifying a pathogen.
What are Koch’s rules for identifying a pathogen?
- The suspect of causation agent must be found in every case of the disease and be absent from healthy hosts.
- Agent is isolated and grown outside of host.
- If agent is introduced to healthy host, the individual must get disease.
- Same agent must be isolated from the disease, experimental host.
What were Koch’s lab contributions?
Simple staining techniques, first photomicrograph of bacteria, first photomicrograph of bacteria in diseased tissue, techniques for estimating CFU/ml, number of bacteria in a solution, based on a number of colonies, formed after inoculation onto a solid surface. As well as use of steam to sterilize media, petri dishes, aseptic techniques with loop, and identifying bacteria as distinct species.
Richard Petri contribution?
Petri dish
Fanny Hess contribution?
Agar used as solidifying agent.
Hans Christian Gram (Denmark 1853-1938)
Develop staining to identify two large groups of bacteria thin/thick cell wall
Define morphology
Study of appearance of an organism with the naked eye
What does it mean to be gram-positive or gram-negative and what colors do they stain?
Gram-positive: stain purple = thick cell wall
Gram- negative: stain red/pink = thin cell wall
Ways to prevent an infection
Sewage/water treatment, pest control, personal hygiene, etc.
Define nosocomical infections
infections acquired due to unclean hospitals and medical practices.
Ignaz Semmelweis (Australia)
Advocated that medical professionals washed hands in order to cause less death/disease. He used chlorinated lime water (raised pH) to prevent puerperal fever ( infection that was killing mothers giving birth in hospitals).
Joseph Lister (England)
Advocated that medical professionals washed hands to cause less death/disease. Used phenol ( organic solvent) for cleaning surgical wounds (antiseptic).
Florence Nightingale (England)
First professional nurse, advocated for sanitary conditions, and established the first nursing school.
John Snow (England)
Epidemiologist who studied the outbreak of cholera ( vibrio cholera) and was able to link the illness to city water pumps.
Edward Jenner (England)
Wondered if cowpox could prevent smallpox. In order to test this, he experimented on a neighborhood boy and then widened his experiment to include 27 other people. Pasteur and others improved process using killed/weakened pathogens ( vaccine) including the term vaccine after the cowpox virus vaccinia. Didn’t invent vaccine, but did coined the word and got credit for it..
Paul Erlich (Germany- early 1900s)
Came up with the idea of a “magic bullet” for syphilis. His idea was to have a chemical that would kill a pathogen, but not the human host. Discovered Salvarsan, and arsenic compound AKA chemotherapy, which are chemicals used to kill microbes.
What do modern microbiologist study?
Bio chem, microbial genetics, molecular biology, recombinant DNA, gene therapy, environmental micro, bioremediation, serology, immunology, and chemotherapy.
Alexander Fleming (1920s)
Discovered penicillin
Bio chem
Study of metabolism (all the chemical reactions in a cell)
