Brief History of Microbiology

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then broke and tilted a few flasks and noticed that they became cloudy from contamination

Came up with the theory of biogenesis = ALL life creates other life (Theory of Life)

7. Explain what is important about the scientific method, including observations, hypothesis, conclusion. Why are certain ideas called a theory, like the germ theory of disease?

Scientific Method:

Observation

Ask Questions which lead to possible explanations = hypothesis

Perform experiment - to prove or disprove the hypothesis

Theory - general explanation for natural phenomenon based on lots of experiments and people evaluating it.

Germ Theory of Disease:

States that many diseases are caused by microorganisms.

These small organisms, too small to see without magnification, invade humans, animals, and other living hosts. Their growth and reproduction within their hosts can cause a disease.

8. How was the discovery of spores and sterilization important to the development of aseptic technique? (see Tyndall and Cohn, Holmes and Semmelweis and Lister)

Sterile = absence of any form of life

John Tyndall provided the initial evidence that some of the microbes in dust and air have very high heat resistance and that particularly vigorous treatment is required to destroy them. Later, the discovery and detailed description of heat-resistant bacterial endospores by Ferdinand Cohn, a German botanist, clarified the reason that heat would sometimes fail to completely eliminate all microorganisms. The modern sense of the word sterile, meaning completely free of all life forms (including spores) and virus particles, was established from that point on. The capacity to sterilize objects and materials is an absolutely essential part of microbiology, medicine, dentistry, and some industries.

Dr. Oliver Wendell Holmes, an American physician, observed that mothers who gave birth at home experienced fewer infections than did mothers who gave birth in the hospital; and the Hungarian Dr. Ignaz Semmelweis showed quite clearly that women became infected in the maternity ward after examinations by physicians coming directly from the autopsy room. The English surgeon Joseph Lister took notice of these observations and was the first to introduce aseptic (ay-sep′-tik) techniques aimed at reducing microbes in a medical setting and preventing wound infections. Lister’s concept of asepsis was much more limited than our modern precautions. It mainly involved disinfecting the hands and the air with strong antiseptic chemicals, such as phenol, prior to surgery. It is hard for us to believe, but as recently as the late 1800s surgeons wore street clothes in the operating room and had little idea that hand washing was important. Lister’s techniques and the application of heat for sterilization became the foundations for microbial control by physical and chemical methods, which are still in use today.

9. Differentiate among the terms nomenclature, taxonomy, classification and phylogeny relative to the 3 domains of life and the various kingdoms.

Nomenclature - A set system for scientifically naming organisms, enzymes, anatomical structures, and so on.

Taxonomy - The formal system for organizing, classifying, and naming living things.

Phylogeny - The scheme that represents the natural relatedness (relation by descent) between groups of living beings.

10. Know the levels of classification in taxonomic categories, and how to use binomial nomenclature correctly.

Hierarchical Levels of Classification (Dumb Kids Playing Chase On Freeway Go Splat):

Domain

Kingdom

Phyllum

Class

Order

Genus

Species

How to use binomial nomenclature correctly:

The entire two-part name must be written in italics (or underlined when handwritten).

The genus name is always written first.

The genus name must be capitalized.

The specific epithet is never capitalized.

Chapter 3: Tools of the Microbiology lab

1. Explain what the Five I’s mean and what each step entails: inoculation, incubation, isolation, inspection, and identification

Inoculation: to cultivate or culture microorganisms one introduces a tiny sample into a container of nutrient medium, which provides an environment in which they multiply

Live culture added to an environment to grow (sterile)

Incubation: creates the proper growth temperature and other conditions; promotes multiplication of microbes over a period of hrs, days, and weeks; produces a culture: the visible microbe in or on the medium

Compatible growing environment for that type of cell

Ex: temperature, nutrients, oxygen, pressure, chemical = physical & chemical factors

Isolation: the result of inoculation and incubation is isolation of the microbe; microbes may take the form of separate colonies on solid media, or turbidity in broths; taking a bit of growth from an isolated colony and inoculating a separate medium; makes pure culture that contains only a single species of microbe

Separate the cells through

Streak dilution

Loop dilution

Pour plate

Dilute mixture of cells to single isolated cells

Grow to form isolated colonies

Plate w/ all colonies are similar (no contaminants) = pure culture

Inspection: colonies or broth cultures are observed macroscopically for growth characteristics that could be useful in analyzing the specimen contents

Look at colonies and cells (microscope)

Identification: determining

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