Microbiology Test 1 Answers – Flashcards
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| What type of organisms fall under Prokaryotes? |
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| Bacteria |
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| What are the types of organisms that fall under the category "Eukaryotes"? |
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| Fungi, protozoa, algae, helminths |
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| What types of organisms fall under Archeae? |
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| Archaeabacteria |
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| What types of organisms do not fall under the classifications Eukaryotes, Prokaryotes, or Archaea? |
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| Viruses and prions. |
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| Function: Rough ER |
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| surface for ribosome to sit on and is site of protein synthesis |
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| Function: Smooth ER |
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| site of lipid synthesis |
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| Function: Golgi body |
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| protein folding/modification, sugar synthesis to add proteins |
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| Function: nucleus |
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| DNA storage/replication |
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| Function: mitochondria |
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| ATP synthesis (respiration) |
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| Function: chloroplast |
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| site of photosynthesis |
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| Function: lysosome |
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| digestion, self destruction |
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| Function: cytoplasmic membrane |
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| phospholipid bilayer with proteins to transport in and out |
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| Function: cell walls |
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| adds structure/protection (only in plants, fungi, algae, some protozoa) |
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| Function: glycocalyx |
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| communication, adherence, protection; in cells without cell walls and is a loose sticky carbohydrate coating |
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| Antiport |
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| Active transport where 1 molecule goes with the gradient and is coupled to the movement of another molecule moving against the gradient. |
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| Symport |
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| Active transport where two molecules are moved across the membrane in the same direction. |
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| Uniport |
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| Active transport where only one molecule is transported across the membrane. |
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| Active transport requires ___. |
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| ATP |
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| Endocytosis |
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| is phagocytosis where molecules are engulfed in the cell by wrapping the cell membrane around the molecule. |
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| Facilitative diffusion does/does not require energy. |
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| does not |
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| Two types of glycocalyces and their definitions. |
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| Capsule: tight, organized repeated units, protection from dessication and identification by host Slime layer: loose for attachment, keeps cell hydrated |
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| Polar flagella |
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| One of few located on only one end |
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| Peritrichous flagella |
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| Flagella covering entire cell |
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| Endoflagella |
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| inside cell membrane |
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| Function: basal body |
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| anchors flagella into cell wall |
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| Flagella run |
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| cell moves in one direction by counter-clockwise rotation of flagella to stimuli, which can be either light or chemical |
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| Flagella tumble |
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| random movement due to clockwise rotation of flagella |
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| Fimbriae |
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| nonmotile, used for adhesion, important in biofilms |
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| pili |
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| longer than fimbriae, shorter than flagella; can be used to exchange genetic material; movement by sticking and pulling self forward |
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| Bacterial cell walls are composed of ___________. |
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| peptidoglycan |
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| Gram positive bacteria stain _______ because ________. |
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| purple; it absorbs the crystal violet dye |
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| Gram negative bacteria stain _______ because ________. |
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| pink; it absorbs the counterstain, safarin |
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| Teichoic acids |
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| part of the peptidoglycan of gram + bacterial cell walls, which may be linked to proteins and help anchor cell to surface or membrane to wall |
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| LPS (lipopolysaccharides) |
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| in the membrane of gram - bacteria; is an endotoxin (that is technically on the outside); lipid A of the LPS leads to fever, inflammation, and shock because it elicits an immune response |
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| Cytoplasmic membrane |
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| phospholipid bilayer; 1/2 mass is proteins; controls transportaion in/out of cell; stores energy (no mito) and harvesting of light energy (no chloro) |
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| Endospores |
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| highly durable bacteria cell only formed by certain bacteria; one cell gives one spore; 1/2 DNA is degraded |
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| Endospores |
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| highly durable bacteria cell only formed by certain bacteria; one cell gives one spore; 1/2 DNA is degraded |
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| Endospores |
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| highly durable bacteria cell only formed by certain bacteria; one cell gives one spore; 1/2 DNA is degraded |
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| Inclusions |
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| storage vessicles; deposits of nutriens within prokaryote cell; gas containing vesicles in cyanobacteria; |
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| What are the steps in the Gram stain procedure? |
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| 1. Smear bacteria on the slide before giving it time to dry and heat fixing. 2. Flood the slide with crystal violet for one minute, then rinse with water. 3. Flood slide with iodine to make the dye less soluble. 4. Wash the slide with decolorizing agent and then water. 5. Flood slide with safarin as a counterstain. Then wash with water and let dry. |
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| Organisms can be classified into these two groups based on their source of carbon: |
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| autotrophs: inorganic C heterotrophs: organic C |
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| Organisms can be categorized into these two groups based on their source of energy: |
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| Chemotrophs: redox reactions Phototrophs: light |
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| Organisms can be categorized into two groups based on their source of electrons: |
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| organotrophs: organic compounds lithotrophs: inorganic compounds (hidrogen gas, NO2-, H2S, Fe2+) |
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| Photolithoautotroph examples |
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| purple and green sulfur bacteria; cyanobacteria |
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| Photoorganoheterotroph examples |
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| purple nonsulfur bacteria; green nonsulfur bacteria |
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| chemolithoautotrophs examples |
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| sulfur-oxidizing bacteria, hydrogen oxidizing bacteria, nitrifying bacteria |
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| chemoorganoheterotrophs examples |
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| most non-photosyn. microbes (bacteria, fungi, protists, archaea) |
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| obligate aerobes |
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| must have oxygen |
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| facultative anaerobes |
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| like and grow well with oxygen, but can survive through other means if necessary |
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| obligate anaerobes |
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| can only grow with no oxygen; most use anaerobic respiration; oxygen kills |
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| aerotolerant anaerobes |
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| don't use oxygen but aren't harmed by it |
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| microaerophiles |
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| like between 2 and 10% oxygen (very little) |
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| toxic forms of oxygen: |
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| 1.singlet oxygen (photosynthesis) 2. superoxide radicals (aerobic and anaerobic resp) 3. peroxides (superoxide dismutase) 4. hydroxides (ionizing radiation or incomplete reduction of hydrogen peroxide) |
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| How do cells get rid of singlet oxygen? |
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| (Formed during photosynthesis) Carotenoids are used to remove excess energy |
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| How do cells get rid of superoxide radicals? |
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| (Formed during aerobic and anaerobic respiration); Aerobes produce superoxide dismutases to detoxify |
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| How do cells get rid of peroxide anions? |
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| (Formed by superoxide dismutase); Aerobes contain either catalaseor peroxidase to detoxify peroxide anion |
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| How do cells get rid of a hydroxyl radical? |
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| (Formed from ionizing radiation or incomplete reduction of hydrogen peroxide); aerobes use catalse and peroxidase, so this is not a threat |
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| What do cells use nitrogen for? |
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| N is needed to synthesize nucleotides, proteins, carbohydrates, some lipids, and cofactors. |
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| What do cells require phosphorus for? |
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| It is used for ATP, phospholipids, DNA/RNA, and proteins. |
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| What do cells require sulfur for? |
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| It is required for cysteine and methianine and disulfide bonds. |
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| Growth factor |
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| any organic compound an organism needs but cannot produce itself (such as essential aa's, certain nucleotides in certain organisms, NADH in some, and vitamins) |
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| vitamin |
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| small organic molecule that can act as a cofactor |
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| Temperature affects on growth |
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| Proteins can denature; lipid-containing membranes of cells and organelles can change ridigity; optimum temp is usually closer to max than min |
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| psychrophiles |
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| like cold <15 degree C |
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| mesophiles |
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| like temps between 20-40 degree C |
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| thermophiles |
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| like temps between 45-70 degree C |
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| hyperthermophiles |
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| like temps 80+ degree C, near ocean vents |
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| pH affects on growth: |
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| affects H bonding and protonization |
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| neutrophiles |
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| pH 6.5-7.5 |
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| acidophiles |
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| ph < 6.5 |
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| alkalinophiles |
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| pH > 7.5 |
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| functions of water for cells: |
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| maintain cell rigidity, chemical reactions, maintains osmotic and hydrostatic pressure |
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| hypotonic solute |
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| [solute] is less than cell's []; water will rush into cell to even [] and cell swells |
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| hypertonic solution |
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| [solute] is higher than cell's []; water exits and cell shrinks |
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| obligate halophiles |
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| must live in salt, up to 30% |
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| facultative halophiles |
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| can tolerate high [salt] (organisms that live on skin) |
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| barophiles |
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| organisms that live under extreme pressure |
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| antagonistic relationship |
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| one organisms kills other |
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| synergistic relationship |
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| beneficial to both organisms, but they do not have to be together |
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| sympiotic relationship |
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| interdependent |
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| types of symbiotic relationships: |
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| mutualism: both benefit commensalism: one benefits parasitism: one benefits, one harmed |
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| biofilm |
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| complex relationships among numerous bacteria that forms on surfaces often as a result of quorum sensing |
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| quorum sensing |
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| process by which bacteria respond to changes in microbial density by utilizing signal and receptor molecules |
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| parts of the bacterial growth curve: |
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| x axis - time; y axis - log of cell# 1.lag phase 2.log (exponential) phase 3. stationary phase 4. death (decline)phase |
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| Defined media |
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| composition is known exactly |
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| Complex media |
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| composed of digested things from other organisms |
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| Selective media |
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| only certain organisms will grow on it |
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| Differential media |
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| allows visible differences between different bacteria |
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| Anaerobic growth techniques |
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| 1.stab culture 2.reducing media (liquid) 3. plates grown in gaspack jars; all work in anaerobic box |
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| Microaerophile growth techniques |
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| require 3-10% oxygen; in a CO2 incubator; grown in a gaspack jar (aka candle jar) |
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| Enrichment culture |
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| favors growth of specific bacteria over background microflora |
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| Direct methods for measuring microbial growth: |
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| 1.viable plate count 2.membrane filtration 3.visual cell count 4.flow cytometry 5.most probable # |
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| Viable plate count |
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| Dilution samples are made from the original colony, assume each colony is derived from 1 cell and do backwards math |
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| membrane filtration |
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| filter cells and then count growth colonies; good for small # |
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| visual cell count |
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| known volume in squares viewed under scope and physically count; main disadvantage is dead cells are also counted |
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| flow cytometry |
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| used for euk cells; shoot light across liquid stream w fluor detector and light scatter that helps with size and shape; sort cells based on characteristic |
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| most probable number |
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| used for bacteria; live cell count; bacteria that don't grow well on solid media; take original solution, dilute it 2x, innoculate 5 tubes from each; look result up on most probable # table |
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| indirect method of measuring microbial growth |
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| measures turbidity using a spectrophotometer; relationship preknown between count and turbidity using plate count |
