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59 Cards in this Set
- Front
- Back
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Growth of microbes.... |
increase in number of cells, not size one cell becomes a colony of millions of cells ex: E.coli will divide every 20 mins |
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Control of growth is important for? |
infection control growth of industrial and biotech organisms i.e. anitbiotics |
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Factors regulating growth? |
nutrients environmental conditions generation time |
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what are environmental conditions? |
temp, pH, osmotic pressure |
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chemical requirements: |
water!!! Elements: "CHOPSN" Carbon, Hydrogen, Oxygen, Phosphorus, Sulfer, and Nitrogen Trace elements: K, Na, Ca, Mg, Mn, Zn, Fe, Mo, Cu, Cl ( Metalic- have a charge; usually to make enzymes work)
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Organic |
source of energy (glucose) vitamins (coenzymes) some amino acids --purines --pyrimidines |
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Nutritional categories |
Carbon sources: CO2 = autotroph "self-feeder" Organic=hetertroph "other feeder" |
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energy sources (electron or hydrogen atoms) |
sunlight ( where the cell gets its energy from) = phototroph organic ex: cows eat grass; humans eat the cow) = chemotroph |
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Chemoorganic autotrophs |
use ORGANIC molecules for energy use INORGANIC molecules for carbon (CO2) |
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Lithotroph (odd guys) |
use INORGANIC molecules for energy use INORGANIC molecules for carbon as well important in deep sea life --sulfur vents |
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Chemoheterotrophs |
gets energy from ORGANIC molecules gets carbon from ORGANIC molecules ex: humans |
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Saprobe: |
lives on organic matter of DEAD organisms ----decomposes |
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parasite: |
lives on organic matter of LIVING host=pathogens |
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What is movement of water called? |
Osmosis |
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Define Osmosis |
movement of water across a semi-permeable membrane (plasma membrane) |
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Diffusion of water |
Isotonic, hypotonic, hypertonic ** water molecules are always trying to dilute solutes! |
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Isotonic |
same solutes inside as outside the cell |
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hypotonic |
solutes are more concentrated inside the cell |
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hypertonic |
solutes are more concentrated outside the cell; water rushes out |
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Passive diffusion |
osmosis |
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facilitated diffusion |
higher to lower concentration, carrier molecule |
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Active transport |
lower to higher, takes ATP |
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group translocation |
lower to higher with chemical change |
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bulk transport |
endocytosis, phagocytosis, pinocytosis |
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environmental factors the influence growth |
temp O2 pH osmotic pressure others: radiation, atmospheric pressure |
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psychrophiles |
cold-loving |
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mesophiles |
moderate temp-loving 20-40 degrees (humans) optimum about 37 degrees |
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thermophiles |
heat-loving |
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Temp optima |
** each has a min, optimum, and max temp. ** there is a temp minimum; after optimum, slower until maximum. 1 degree over max= cell death |
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Death above the max temp comes from ... |
enzyme inactivation (like an egg frying) |
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Obligate aerobes |
require O2 |
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facultative anaerobes |
can use O2 but also grow without it |
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obligate anaerobes |
die in the presence of O2, no tolerance ex* your colon lack O2 yet harbors trillions of bacterial cells- obligate anaerobes. |
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Aerotolerant |
do not use O2 but can grow when it is present *often ferment glucose to lactic acid |
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microaerophiles |
require O2 but grow only in concentrations lower than atmospheric pressure ("micro") |
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caphriophiles |
prefer higher CO2 concentrations 2-10% ex: in your mouth, breathing out=bathing them in CO2 concentrations |
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Toxic forms of oxygen |
Singlet oxygen 1/2 O2- very reactive superoxide free radicals O2- peroxide anions O2-2 hydroxyl radical OH- very reactive |
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Brewer's Jar |
takes all the O2 out of the environment used in lab to create an anaerobic environment gas pack takes H2O and turns it into H2 and CO2 |
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candle jar |
used to create a microaerophilic and caphophilic environment candle burns most of the O2 and provides low O2, high CO2 |
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pH range for growing bacteria |
6.5-7.5 (in humans) |
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Acidic conditions |
below pH4 **preservative for pickles, sauerkraut, cheeses |
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Acidophiles |
can live at low pH many bacteria and viruses service low pH of stomach to infect intestines *** Helicobacter pylon |
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Osmotic pressure |
bacteria 80-90% water high salt in surrounding environment leads to water loss and plasmolysis cell's plasma membrane shrinks, cell growth inhibited. ex: salt on slug |
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preserving high osmolarity |
salted fish jerky honey sweetened condensed milk |
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Hypotonic media |
is low osmolarity; may lyse bacteria without cell walls |
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ecological associations: Symbiotic |
close nutritional relationship **deep ocean vents- 2 worms (lithoautotrophes) waste products are glucose=food |
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mutualism |
both benefit |
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commensalism |
commensal benefits, host no harmed ex: clown fish and sea anemone |
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parasitism |
parasite benefits, host harmed |
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What is Binary Fission? |
bacteria dividing it is not linear, after a replication event, twice the amount of bacteria are represent |
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Lag Phase |
working out what enzymes are needed ext. |
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Log Phase (exponential) |
growing as fast as possible most likely when symptoms become apparent |
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stationary phase |
real crowded- nutrients run out-waste building-dying cells-no net change |
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death phase |
decline phase nothing but waste produced |
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measuring growth: direct methods: |
count individual cells or representations of individual cells hemocytometer- small amount of culture on side to physically count and back calculate plating |
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indirect methods |
measure effects of bacterial growth TURBIDITY (cloudyness) with a spectrophotometer enzymatic activities |
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metabolic activity |
measure gas/protein output more cells=more gas/protein output |
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Dry weight |
remove all H2O; weigh whats left correlate to numbers |
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Alternative means of bacteria division? |
Budding, conidiospores and fragmentation |
