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47 Cards in this Set
- Front
- Back
List Macro/Micronutrients |
macro: C, N, P, S, O (all cells need) micro: Fe (borderline), Cu, Na, Mg, Mn |
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How to name cell metabolism |
Chemo/photo (chemical/light for energy) organo/litho (organic/inorganic e- source) hetero/auto (organic/inorganic carbon source) |
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What metabolism are humans? |
Chemoorganoheterotroph |
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Name metabolism of E. coli? |
Chemoorganoheterotroph |
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Name metabolism of cyanobacteria? |
photolithoautotroph |
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Only combo of metabolism that doesn't exist (probably) |
chemoorganoautotroph (chemical energy source, organic e- source and inorganic carbon source) (why would you break down C for energy and then use sunlight for carbon source) |
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Effect of nutrient conc. on bacterial growth |
Higher conc. makes the rate of growth be higer, but it will level off sooner to a rate near zero. |
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2 types of aerobic microbes and definitions |
Obligate: require O2
microaerophile: grow best in low levels of O2 |
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3 types of anaerobic microbes and definitions |
aerotolerant: aren't harmed, don't use it obligate: cannot grow when O2 is present Facultative: Can grow in absence, but grow better with O2 present. |
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catalase test (what is it?) |
tests for catalase with hydrogen peroxide, if catalase is present h2o2 will turn into water and oxygen (bubbles). |
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water availability, number that bacteria need, how is it defined? |
aw, pure water has value of 1.0, most bacteria need >0.9, is defined as pressure of air in equilibrium with substance/ " " of water |
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Why does water move into cytoplasm? What will make it flow out? |
Cyto tends to have a high solute conc. than external enviro If enviroment is hypotonic (lower solute conc. in cell than enviro) water will flow out. |
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How can water loss be prevented in hypotonic sln? |
Pumping inorganic ion from enviroment Synthesis of organic solutes |
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Temperature's effect on cells (3) |
Effects macromolecular structure, membrane fluidity, enzyme fxn |
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What are psychrophiles, and their min/optimum/max temps |
Microbes which prefer cold temperatures, 0/15/20 celcius |
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What is pyschrotolerance, found where? |
Mesophiles which are able to grow ~0C, optimum growth is 20-40C found in soil, in your fridge |
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Hyperthermophiles, found where and at what temps? |
Found in boiling springs, water heaters, hydrothermal vents, optimum temps are 50-350C |
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Hyperthermophilic adaptations (4) |
amino acid subs to produce heat tolerant folds inc. in ionic bonds between acidic and basic residies certain solutes stabilize proteins Modifications in cyto mem (mono layer instead of saturated bilayer) |
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2 states of media and advantages |
solid (agar) - polysac from algae, gels @ 37C, rarely degraded by microbes, solidifying agent liquid (broth) |
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2 types of media, definition |
Complex - unknown chemical comp Defined - known " " |
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3 types of specialized media, uses and an example |
selective - isolation of microbes with spec. properties (brilliant green agar) differential - allows for certain microbes to be recog based on visual cues (EMB agar)
enriched - increase population of microbes with spec. property (MacConkey Agar) |
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3 ways of obtaining pure culture |
streak/spread/pour plate |
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Direct counting adv./disadv |
adv: cheap, fast and easy dis: can't differentiate between viable/dead cells |
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Viable cell count method, which dilution to count? |
Do a series of 10x dilutions, spread plate all, incubate and count plate with 25-250 colonies |
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How to conc. cells from a dilute sample? |
use filters with very small holes, all small water molecules will go through but the bacteria will stay |
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What is turbidity, what is used to measure it? |
Turbidity is the amount of light that a substance absorbs, measured with a spectrophotometer. |
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(Dis)advantages of spectrophotometer |
adv: cheap, fast, easy dis: rough measure, doesn't distinguish between living/dead cells. |
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4 phases of growth curve |
lag (preparing for growth, making proteins for replication) log (growth is constant and exponential) stationary (replication rate = death rate) death phase (nutrient are depleting, cells are dying at steady rate) |
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measuring live cells with spectrophoto (turbidity) over time vs. actual differences on curve |
turbidity starts off higher than viable cells, caps off earlier as it cannot read limits so close to 1, stays higher in death phase |
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def: generation time |
time to double the population in exponential phase |
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def: growth phase |
number of generations per unit time (inverse of gen. time) |
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def: growth yield |
The max pop density and/or amount of cellular material produced by the culture |
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purpose of using continuous culture, how is it done |
Used to keep microbes in exponential growth (to harvest products) done by constantly pumping out and in nutrients/waste |
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Microbial filtration uses, made of (pore sizes)?, problems |
Used to seperate microbes from field sample, made of polymer and have pore size of 0.2 or 0.45 micron, can use 10-100nm for viruses too problems include large particles clogging and needing high pressure for viscous liquids |
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What is depth filter, purpose? |
Fibrous sheet made of paper fibres randomly distributed, used as a "pre-filter" |
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conventional membrane filter consists of?, pore size, uses |
made of cellulose acetate or " " nitrate with variable pore size (non-uniform), used for sterilization |
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Nucleopore filters , uses, pore size, how its made? |
Used for microscopy, has uniform pore size, made by radiation damage, makes cracks which are enlarged by chemical "etching" |
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Temp. manip. uses/problems |
used to denature proteins/nuc acids, kills most microbes, can be used with an autoclave to prevent fluids from evap problems lie with hyperthermophiles, endospores and materials which cant be heated |
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What is an autoclave, how is eff determined |
machine which inc. pressure and temp to sterilize media (121C, 15 psi) eff. determined by destruction of endospores, vegatative cells |
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pasteurization purpose, (dis)advantages, how is it done? |
Destroys pathogens, kills 90-99% of microbes, inc. shelf life does not sterilize, keeps flavour done by heating to high temp for short period of time (eg 72C for 15s and then rapid cooling) |
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EM raditation sterilization, method and uses |
samples bombarded with UV rays of 260-280 nm, damages DNA via formation of thymine dimers exploited to control microbial growth on non-living surfaces/water |
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Radiation sterilization uses, (dis)advantages |
damages proteins and DNA (double strand breaks, e- stray) Used in medical supplies/drugs/labware, food, tissue for grafting adv are higher energy, better pen disadv are cost/hazard, limited to industry |
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3 types of antimicrobial action and effect on (viable) cell count |
bacteriostatic, inhibits growth, no decline in cell count bacteriocidal: kills cells, doesnt dec. total cell count bacteriolytic: makes cells lyse, dec both total and viable cell count |
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2 types of chemical control |
disinfectants: used on non-living surfaces to kill infectious microbes antiseptics: used on living tissue to kill infectious microbes (usually topically) |
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5 properties of good microbe killer |
wide range of targets, isnt corrosive/toxic, doesnt leave residue/fumes, cheap, temp stable |
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How to choose method? Qs to ask? (5) |
What microbe are present, #, endo? All need to die? What object is treated, worry about toxicity? if using phys. method, how long is needed? |
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Measuring effectiveness method |
Decimal reduction time (D value), time req. to kill 90% of microbes under spec. conditions |