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116 Cards in this Set
- Front
- Back
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Why did people believe in spontaneous generation?
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Because they they had no way to explain why maggots came out of dead animals, or microbes appeared in liquids.
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Why didn't spontaneous generation proponents believe Redi proved anything?
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Because Spallazani sealed his flasks, and they believed that air was necessary for life.
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How was Pasteur finally able to disprove the theory of spontaneous generation?
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He used flasks with s-curve necks that allowed air to get in, but caused the bacteria to get trapped at the bottom of the curve.
He proved that microbes are in fact in the air, and the air itself does not create microbes. |
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Who was the first person to actually observe microbes through a microscope?
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Anton van Leeuwenhoek
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What role do microbes play in pest control?
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Pests can be controlled by using bacteria that cause disease in insects, rather than using chemicals. These are better because they are specific to the insect and don't harm the environment.
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What role do microbes play in recycling elements?
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They break down dead plants & animals and convert the 5 essential elements into forms other organisms can use.
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What are the 5 things required by all living organisms?
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Carbon, oxygen, nitrogen, sulfur & phosphorous.
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What role do microbes play in "normal microbiota"?
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Aka "normal floral," these are microbes that inhabit our bodies. Mostly they are neutral; sometimes they benefit us; sometimes they make us sick.
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What role do microbes play in sewage treatment?
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Bacteria decompose the organic matter in sewage into CO2, nitrates, phosphates, sulfate & inorganic compounds.
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What is mineralization?
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The process of bacteria decomposing organic matter in sewage into CO2, nitrates, phosphates, sulfate & inorganic compounds.
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What role do microbes play in human insulin production?
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Through recombinant DNA technology, bacteria become mini biochemical factories. They insert the gene for human insulin into bacteria, and they produce it cheaply.
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What role do microbes play in vaccine production?
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Microbes & their toxins can be used as vaccines. Some microbes can be genetically engineered to produce vaccine components.
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What field of microbiology is the following related to?
Studies biodegradation of toxic wastes. |
Microbial ecology.
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What field of microbiology is the following related to?
Studies the causative agent of AIDS. |
Virology.
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What field of microbiology is the following related to?
Studies the production of human proteins by bacteria. |
Microbial genetics & Molecular biology
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What field of microbiology is the following related to?
Studies the symptoms of AIDS. |
Immunology.
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What field of microbiology is the following related to?
Studies the production of TSS toxin by S. aureus. |
Microbial physiology.
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What field of microbiology is the following related to?
Studies the life cycle of Borrelia burgdorferi. |
Microbial ecology.
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What field of microbiology is the following related to?
Develops gene therapy for a disease. |
Molecular biology.
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What was the contribution to microbiology?
Avery, MacLeod, McCarty |
Proved that DNA is the hereditary material.
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What was the contribution to microbiology?
Beadle & Tatum |
Showed that genes code for enzymes.
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What was the contribution to microbiology?
Berg |
Spliced animal DNA to bacterial DNA.
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What was the contribution to microbiology?
Dubos |
Discovered antibiotics produced by bacteria.
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What was the contribution to microbiology?
Ehrlich |
Used the first synthetic chemotherapeutic agent.
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What was the contribution to microbiology?
Fleming |
Discovered penicillin.
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What was the contribution to microbiology?
Hooke |
First to observe cells in plant material & name them.
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What was the contribution to microbiology?
Iwanowski |
Observed that viruses are filterable.
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What was the contribution to microbiology?
Jacob & Monod |
Discovered how DNA controls protein synthesis in a cell.
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What was the contribution to microbiology?
Jenner |
Developed vaccine against smallpox.
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What was the contribution to microbiology?
Koch |
Proved that microbes can cause disease.
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What was the contribution to microbiology?
Lancefield |
Proposed a classification system for streptococci based on antigens in their cell walls.
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What was the contribution to microbiology?
Lederberg & Tatum |
Discovered that DNA can be transferred from one bacterium to another.
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What was the contribution to microbiology?
Lister |
First to use disinfectants in surgical procedures.
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What was the contribution to microbiology?
Pasteur |
Disproved spontaneous generation.
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What was the contribution to microbiology?
Stanley |
First to characterize a virus.
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What was the contribution to microbiology?
Van Leeuwenhoek |
First to observe bacteria.
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What was the contribution to microbiology?
Virchow |
Said living cells arise from preexisting living cells.
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What was the contribution to microbiology?
Weizmann |
Used bacteria to produce acetone.
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Who designed the nomenclature system for naming and classifying organisms?
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Carolus Linnaeus.
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How do you name an organism?
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First is its genus (capitalized), and then it's species.
Must be underlined or italicized. |
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What are the 5 kingdoms?
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Procaryotae (Monera)
Protista Fungi Plantae Animalia |
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How are scientific names chosen?
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To describe the organism, honor a researcher, or identify the habitat or niche of a species.
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Describe the microbe: algae
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* Cell wall made of cellulose
* Photosynthetic |
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Describe the microbe: bacteria
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* Cell wall made of petidoglycan
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Describe the microbe: fungi
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* Cell wall made of chitin
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Describe the microbe: protozoa
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* Complex cell structure lacking a cell wall
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Describe the microbe: viruses
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* Not composed of cells.
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What are some supermarket products made by microbes?
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Yogurt, sour cream, cheese, protein supplements, bread, wine, beer, sauerkraut, vinegar.
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How many meters is 1 micrometer?
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1/1,000,000 of a meter.
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How many meters is 1 nanometer?
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1/1,000,000,000 of a meter.
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How many meters in 1 angstrom?
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1/10,000,000,000 of a meter
No longer an official unit of measure. |
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How many nanometers in a micrometer? How many angstroms in a micrometer?
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10^3 nanometers
10^4 angstroms. |
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What is an illuminator?
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The light source of a compound light microscope.
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How do you calculate the total magnification of a specimen?
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Multiply the objective lens magnification by the ocular lens magnification.
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What is the ocular lens magnification of most microscopes used in microbiology?
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10x
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What is resolution?
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The ability of the lenses to distinguish fine detail and structure - to distinguish between two points a specified distance apart.
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What can you say about wavelength and resolution?
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The shorter the wavelength of light used, the greater the resolution.
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What are the 5 main components of a compound light microscope?
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Ocular lens
Objective lens Diaphragm Condenser Illuminator or light source |
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What is the magnifying power of a low power objective lens?
High power? Oil immersion? |
10x
40x 100x |
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Which type of microscope would be best to observe:
Stained bacterial smear |
Compound light microscope.
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Which type of microscope would be best to observe:
Unstained bacterial cells when the cells are small and no detail is needed. |
Dark-field microscope
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Which type of microscope would be best to observe:
Unstained ive tissue when it is desirable to see some intracellular detail. |
Phase-contrast microscope.
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Which type of microscope would be best to observe:
A sample that emits light when illuminated with ultraviolet light. |
Fluorescent microscope.
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Which type of microscope would be best to observe:
Intracellular detail of a cell that is 1 micrometer long. |
Illuminator or light source.
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Which type of microscope would be best to observe:
Unstained live cells in which intracellular structures are shown in color |
Differential interference contrast.
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What is the refractive index?
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A measure of the relative velocity at which light passes through a material. Can be changed with staining.
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What is the resolution limit for compound light microscopes?
What is it's greatest possible magnification? |
.2 micrometers
2000x |
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What does increasing the objective lens diameter, or adding immersion oil do?
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Increases the resolving power
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What type of microscope is it best to use unstained cells with?
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Anything other than the standard compound light microscope.
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What is a darkfield microscope used for?
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Observing LIVE microbes that are invisible in ordinary light microscopes, cannot be stained by standard methods, or are distorted by staining.
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What is different about a darkfield microscope?
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It has an opaque disk in the condenser. This means that only light that is reflected off the specimen enters the objective lens.
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What is a phase-contrast microscope used for?
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Detailed examination of the internal structures of LIVING organisms.
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What are the advantages of the phase-contrast microscope?
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It isn't necessary to fix or stain the specimen (microbes won't get killed)
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What would a slide under a darkfield microscope look like?
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Dark background w/ specimen illuminated.
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What would a slide under a phase-contrast microscope look like?
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Different degrees of brightness.
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What is a differential interference contrast (DIC) microscope?
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It is similar to phase-contrast b/c it takes advantage of differences in refractive indexes. It differs because it uses two beams of light instead of one, and prisms split these beams
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What would a slide look like in a DIC microscope?
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Bright, contrasting colors, appears almost 3D.
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What is fluorescence microscopy?
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Takes advantage of the fluorescence of substances. Has a special lense filter that enables it to see the light given off.
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What is fluorescent microscopy used most for?
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A diagnostic technique called fluorescent-antibody technique/immunofluorescence.
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What would a slide look like in a fluorescent microscope?
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Luminescent, bright objects against a dark background.
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What are the 2 types of electron microscopes used for?
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To examine objects smaller than .2 micrometers, like viruses or internal cell structures.
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What are 3 ways an electron microscope different?
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They use a beam of electrons instead of a beam of light.
It uses electromagnetic lenses instead of glass lenses It's resolving power is far greater than the others (b/c electrons have short wavelengths) |
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How does a transmission electron microscope work?
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A finely focused beam of electrons from an electron gun passes through an ultrathin section of specimen on a copper mesh grid.
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What would a slide look like in a transmission electron microscope?
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Many light and dark areas.
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Are stains used with electron microscopes?
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Yes. Positive or negative staining. Heavy metal salts are used.
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Advantages & disadvantages of transmission electron microscopy?
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Advantages:
*High resolution * Good for examining different layers of specimens Disadvantages: * Only a very thin section of a specimen can be studied (b/c electrons can't penetrate well) * Specimens must be fixed, dehydrated & viewed under a vacuum (DEATH, SHRINKAGE, DISTORTION). |
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What is an artifact?
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A structure that appears as a result of the method of preparation of a slide.
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What is the scanning electron microscope useful for?
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Studying the surface structures of intact cells & viruses.
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What is the resolution of the scanning electron microscope?
How much magnification? |
20 nm
1000x-10,000x |
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What problem does scanning electron microscopy overcome?
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Sectioning is not necessary as with the transmission electron microscope.
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What would a slide look like in a scanning electron microscope?
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Striking 3D view.
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How do you view the image produced by an electron microscope?
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Through an electromagnetic projector lens on a tv-like screen or photographic plate.
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What is the max mag of a compound microscope?
Of an electron microscope? |
2,000x
10,000-100,000x |
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What is the max resoltuion of a compound microscope?
Of an electron microscope? |
.2 micrometers
25nm/20nm |
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What is one advantage of the scanning vs. the transmission electron microscope?
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The scanning allows for a 3D image where you can perceive depth.
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What are acidic dyes used for?
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They are used for negative stains since they stain the background (NOT the cell).
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What are basic dyes used for?
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"Simple" stains because they stain the cells in a smear.
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What do basic dyes stain bacteria?
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Because bacteria have a negative charge (are acidic). The positive charge of the dye is attracted to this negative charge.
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When would you use a simple stain?
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To determine cell shape & arrangement.
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When would you use a differential stain?
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To distinguish kinds of bacteria based up on the interaction of the staining procedure with a particular cell wall structure.
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When would you use a negative stain?
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When you need to determine cell shape, size & the presence of a capsule. It doesn't distort the cell.
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When would you use a flagella stain?
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To determine the # and arrangement of flagella.
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What is a mordant?
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A chemical that intensifies the stain. It also coats structure to make it thicker and easier to see (flagellum).
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What does the counterstain do in the acid-fast stain?
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It stains the colorless non-acid-fast cells so they are easily seen through a microscope.
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What is the Gram stain?
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Divides bacteria into gram-positive & gram-negative.
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What is a gram-positive bacteria?
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Retains the purple color even after decolorization from alcohol.
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What is a gram-negative bacteria?
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Bacteria that loses the purple color after decolorization.
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Why is safranin (counterstain) added during Gram-staining?
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To give some color to the gram-negative bacteria.
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What is the purpose of a counterstain?
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It stains the colorless non-acid-fast cells so they are easily seen through a microscope.
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What is a non-acid-fast bacteria?
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Bacteria whose cell wall lacks the waxy components (stains are usually more soluble in cell wall waxes than alcohol)
Decolorized by acid solutions. |
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What is a decolorizing agent?
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Acid alcohol. Ethanol or ethanol-acetone.
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What step in Gram staining could be omitted?
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The counterstain, because Gram positive cells would be purple and Gram negative would be colorless.
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In order to discern two objects separated by a given distance...
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...the resolving power must be less than or equal to the distance in question.
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What is the acid-fast stain?
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It binds strongly only to bacteria that have a waxy material in their cell walls.
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Will acid-fast bacteria be gram positive or gram negative?
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They will be gram-positive, if they stain at all. Acid fast cells have a high waxy lipid content, which makes them impermeable to most stains. If a stain penetrates, it will not be removed by the decolorizer.
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Will non-acid-fast bacteria be gram positive or negative?
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They can be either gram positive or negative.
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