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Microbiology
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where did the science of microbiology originate
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Microbiology
chapter 1
| Term | Definition |
|---|---|
| Microbiology | the study of microorganisms using a variety of techniques for purposes of visualizations, identification and study of their function. |
| where did the science of microbiology originate | the development of the microscope |
| development of the microscope | started in the 16th century and evolved, the first microscope was produced by a father-son team of Dutch eyeglass makers in 1950 named Zaccharias and Hans Jenssen |
| The first microscope invented was the | Compound microscope |
| compound microscopes consist of | a simple tube with lenses at each end, the magnification through the diaphragm ranged from three times to nine times |
| Anthony Van Leeuwenhoek ( 1632-1723) | Holland Native is considered to be the father of microscopy and is believed to be the first to observe live bacteria and protozoans. his microscope contained only one convex objective lens and is now called a simple microscope. |
| Animalcules | discovered by Van Leeuwenhoek was able to see small life forms that he called animalcules for "little animals" |
| Leeuwenhoek | published their observations in 1678 in a letter to the royal society of London. Is now referred to as the "father of Microbiology" (never related animalcules to microbes to disease) |
| when did scientist finally become convinced that microorganisms exist? | In the late 17th century |
| Hooke, Pasteur, Koch and other | established the definitive relationship between microbes and disease was established later, in what became known as the germ theory of disease |
| Robert Hooke(1635-1703) | an English scientist with remarkable engineering abilities and an interest in many aspects of science. he greatly improved the design and capabilities of the microscope |
| Robert Hooke | published his observations with magnificent drawings in the book "micrographia". requested by the Royal Society of London to confirm Van Leeuwenhoek's findings of animalcules. |
| Electron microscopes. (EM) | Electron microscopes (EMs) are sophisticated 20th-century instruments that use a beam of electrons rather than light as the source of energy to visualize specimens. Magnetic fields instead of optical lenses are used to focus the electron beam, |
| Light microscopes | Use visible light to illuminate and optical lenses to observe enlarged images of specimens. classafied as either simple or compound. |
| Simple light microscope | has a single magnifying lens and a visible light source and can magnify objects approximately 266 times (x266) |
| Compound light microscope | use visible light, usually provided by an electric source, but uses multiple lenses for magnification. |
| Ocular lenses | lenses r lenses close to the eyes, located in the headpiece of the microscope |
| objective lenses | lenses closer to the specimen are located in the body of the microscope and are referred to as objective lenses (each Lense has its own magnifying power) |
| Magnifying power | final magnification of a compound microscope is the product of the enlarging power of the ocular lens multiplied by the power of the objective lens. |
| Monocular | single lens |
| binocular | pair of lenses |
| magnification | lenses magnify by the power to 10 (x10). |
| objective lenses | mounted on a revolving nosepiece and usually magnify x4, x5, x10, x40 or x100 |
| compound microscopes can magnify an object up to | 1000 times |
| example of magnification | an ocular lens with a magnification of 10 times the objective lens with a power of x100 =x1000 |
| photomicrographs or micrograph | photos taken through a microscope |
| dissection microscopes and stereomicroscopes | are low-power microscopes designed for observing larger objects such as insects, worms, plants, dissected objects for further observation. this microscope provides 3 dimensional images to determine surface structures and specific locations on a specimen |
| bright-field microscope | a type of compound microscope, can be used to examine small specimens and some of their details. exhibits a background brighter than the observed specimen and is dependent on altering the light path (refraction) only. |
| bright-field microscope | most specimens require staining for optimal observations, most commonly used to observe sectioned and stained tissues, organs, and microorganisms |
| Dark-field microscopes | unfixed, unstained specimens such as living organisms (bacteria) can be observed with a dark field microscope. a light stop in the condenser prevents the light from going straight through the specimen. |
| Dark-field microscopes | only light from the edges of the condenser lens strikes the specimen at an angle resulting in a dark background and edges of the specimen being illuminated. some bacteria that are difficult to stain (inc spirochetes) is best observed by dark-field |
| Dark-field microscope | motility can be easily observed as the organisms are alive. Bacterial capsules are good candidates to be observed with dark-field microscopes |
| phase-contrast microscopes | first described by Frits Zernike, is done with contrast-enhancing optical instrument that can be used for a wide variety of applications |
| Phase-contrast microscopes | light bends differently as it passes through different densities is the basis for the phase of the light, difference between light and dark areas produces contrast which the phase shift increases |
| Phase-contrast microscopes | high-contrast images of transparent specimens such as living plant and animal cells, microorganisms and thin tissue slices, light interferences patterns, along with the phase shift are used to increase contrast in a Nomarski microscope |
| cell division and phagocytosis are examples of | processes well suited for phase-contrast microscopy |
| fluorenes microscopes | emit light of one color when illuminated by ultraviolet radiation, Fluorescence microscopes are used to visualize specimens that contain natural florescent substances such as chlorophyll or those stained with a fluorescent dye |
| confocal Microscope | a single point of light focuses sequentially across a specimen, avoiding most of the unwanted scattered light that usually obscures and image when the entire specimen is illuminated at one time |
| Marvin Minsky | Invented confocal microscopy, which was patented in 1957 |
| Electronic microscope | sophisticated instruments of the 20th century, use a beam of electrons rather than light as the source of energy to visualize specimens. magnetic field, not optical lenses are used to focus the electron beam, better image resolution than light microscope |
| Electron Microscope | Bacteria can be visualized by light microscopy, but specifics and attachments are best seen which microscope? |
| Transmission Electron Microscopes (TEM) | electron beam travels through an ultrathin sectioned specimen (~100nm in thickness) provides a two- dimensional image of the cell of other object. resolving power of a TEM is approx 0.002 um, 100x greater than can be achieved with a light microscope |
| X500,000 to x1,000,000 | usual magnification of a TEM ranges from |
| Scanning Electron microscopes (SEM) | provides images of high resolution, in contrast to a TEM, a SEM does not require ultrathin sections. scans the surface of an object, producing a three-dimensional image. has a large depth of field that allows the surface of sample to focus at same time |
| x10 to x100,000 | usual magnification that can be achieved with an SEM range from |
| scanning probe microscopy | group of tools used to examine structures down to the atomic level, microscope use a physical probe to scan the surface of the specimen and the data collected generates an image of the structures |
| examples of the (SEM) | Atomic force microscope, scanning tunneling electron microscope (STEM) |
| Atomic Force Microscope (AFM) | uses a finely balanced stylus that touches the surface of the specimen and is moved over its surface, traveling up and down the as it follows surface contours, contours are then complied as a single "topographic" |
| advantage over the standard scanning type of EM | does not need a metallic coating, which may obscure finer details |
| what are types of microscopes that provide 3 dimensional images of a specimen | Scanning Electron microscope and Dissection/ Stereo- microscope |
| Scanning Electron Microscopes | magnification ranges from x10 - x100,000 provide high resolution 3D and don't require samples to be ultrathin |
| Transmission Electron Microscope | magnification ranges from x,500,000 to x1,000,000 pictures taken are electron micrographs, 2d resolution and requires samples to be ultra-thin |
| Scanning probe | |
| light microscope | Uses visible light and optical lenses Either simple or compound Ocular lens Objective lens Final magnification: Multiply the enlarging power of both the ocular and objective lenses Example: ×10 times ×4 = ×40 |
| spontaneous generation | theory that living organisms were produced spontaneously by decay and fermentation, Maggots were believed to arise from spontaneous generation |
| spontaneous generation dilemma | —raising the basic dilemma of “which comes first, the chicken or the egg?” Pasteur, a French chemist, ended the controversy. |
| first serious attack on spontaneous generation theory | arose in 1668 from Francesco Redi and Italian physician, he believed that maggots developed from fly eggs. developed meat into a flask, also placed hay |
| abiogenesis | Life develops from nonliving matter |
| Louis Pasteur | a French chemist, ended the controversy of spontaneous generation; boiled meat in a flask and heated the swan neck flask that air could not enter, no growth present than tilted the neck so organism could reach the meat growth occurred |
| John Needham | claimed victory for spontaneous generation with his experimental observations, boiled chicken in corn broth and placed it in a flask and sealed it microbial growth occurred |
| Joseph Lister - | studied Semmelweis’s observations and hypothesized that airborne microbes play a role in postsurgical Expanded protocols with aerosol disinfection Introduced ‘Aseptic techniques’ |
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sfuller1