| Term | Definition |
|---|
| chemically defined medium | exact chemical composition is known |
| complex media | exact chemical composition varies from batch to batch |
| agar | extract from marine red algae; used to culture media |
| inoculated | intentionally introduced |
| colony | population of cells that arises from a single bacterial cell |
| colony-forming unit | colony arising from a group of the same microbes attached to one another |
| microbiology | the study of microorganisms (too small to be seen with naked eye) |
| microorganisms | bacteria, archaea, algae, fungi, protozoa, viruses |
| bacteria | prokaryotic; usually unicellular |
| bacteria | most abundant organisms on earth; motile |
| bacteria | coccus; bacillus; helical (spirillum) |
| coccus | spherical bacteria |
| bacillus | rodlike bacteria |
| spirillum | helical bacteria |
| proper bacteria naming | Genus species (binomial nomenclature) |
| archaea | less evolved bacteria |
| archaea | prokaryotic; usually unicellular |
| archaea | live in extreme environments |
| archaea | resemble bacteria in common shapes |
| algae | eukaryotic; unicellular or multicellular |
| algae | not plants; plant-like - all are photosynthetic; most water-dwelling; motile |
| fungi | eukaryotic |
| fungi | non-photosynthetic; nonmotile; most are scavengers |
| fungi | range from microscopic to macroscopic |
| protozoa | eukaryotic; unicellular |
| protozoa | most complex unicellular organisms; parasitic; many are water-borne; motile |
| protozoa | complex intracellular organelles; many have cilia/flagella to aid movement |
| viruses | acellular |
| viruses | must inhabit host cell to reproduce; nonmotile |
| viruses | composed of nucleic acid packaged into protein coat; no organelles |
| studying microorganism requires | growing them in controlled manner and making them visible |
| growing microorganisms | achieved by culturing and isolating select organisms |
| microorganisms made visible through | staining methods (most microorganisms are naturally clear) |
| isolating required because | culturing leads to a mix of species |
| colony characteristics | size, shape, color |
| pure cultures | isolated growth of one species of microorganism (obtained in lab artificially) |
| mixed cultures | multiple species of microorganisms (most often found in nature) |
| first step in obtaining pure culture | sterilization of all materials/equipment |
| second step in obtaining pure culture | media must be provided (most often agar plate) |
| culture media | nutrients and environment needed for growth of a microorganism |
| dilution methods | streak plate, pour plate, spread plate |
| clones | descendents of a single organism |
| streak plate method | most common method of dilution; loop is used to streak the mixed sample many times over the surface of an agar plate; loop causes fewer microbes to be distributed in each quadrant until single cells are isolated which will grow into colonies |
| pour plate method | dilution made before samples are put on plate; final diluted sample added to melted agar, mixed, and poured into an empty plate; allows for quantification; could be useful for anerobic bacteria |
| spread plate method | dilution made before sample put on plate; the final diluted sample is spread over agar plate; allows for quantification |
| dilution factor | increases by factor of 10 for every 1 ml |
| number of bacteria/ml | number of colonies x dilution of sample (quantifies amt of bacteria in original sample) |
| ideal growth temperature | most bacteria: 37 degrees C |
| ideal growth pH | 6.5 - 7.5 |
| fixation | heat/chemical treatment that attaches microbe to glass slide |
| gram staining | gram+ and gram- bacteria stain differently because of differences in their cell walls |
| gram+ bacteria | lack the "armor" that gram- bacteria have in cell walls |
| gram staining steps | crystal violet, iodine, decolorization (alcohol), counter stain (safranin) |
| gram+ result | will not decolorize and remains purple |
| gram- result | will decolorize and turns pinkish after counter stain (safranin) |
| purpose of gram staining | eliminate 50% of bacteria right off the bat; certain drugs will treat each, some will treat both; systemic drugs mainly gram-; bacteria either gram+ or gram- |
| bacterial phases of growth | dependent of many things; nutrients, environment, threats; some species pass through entire series of phases in a few days and others retain some surviving cells indefinitely |
| lag phase of growth | initial growth period; number of cells change very little - cells do not reproduce immediately in new medium (1hr - several days) |
| log phase of growth | cells reproduce exponentially; most active growth period; doubling time is constant |
| stationary phase of growth | growth rate slows and number of microbial deaths balances out number of new cells; population stabilizes |
| death phase of growth | number of microbial deaths exceeds the number of new cells formed; continues until population dwindles and possibly dies out entirely |
| turbidity | density of some particle inside some solution; in bacteria is directly proportional to population of bacteria |
| spectophotometer | measures the percent of light transmitted through solution |
| absorbance | light that stays behind; calculated as 100 minus transmittance |
| transmittance | light that gets through; calculated as 100 minus absorbance |
| highest turbidity in bacteria | log phase |
| increase in transmittance | decrease in bacterial population |
| decrease in transmittance | increase in bacterial population |
| increase in absorbance | increase in bacterial population |
| decrease in absorbance | decrease in bacterial population |
| spontaneous generation | forms of life could arise spontaneously from non-living matter |
| 1861 Pasteur Experiment | disproved spontaneous generation; demonstrated that microorganisms are present in the air and can contaminate sterile solutions, but the air itself does not create microbes |
| selective culture media | supress the growth of unwanted bacteria and encourage the growth of desired bacteria |
| differential culture media | makes it easier to distinguish colonies of desired organism from other colonies growing on the same plate; ex: using blood agar for streptococcus - strep will show a clear ring around the colonies where they have lysed the surrounding blood |
Combine with other sets
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