Principles of Micro 4 Flashcards by Vanessa Nwaokocha

what are the two types of cell inclusions in bacteria

glycogen and polyphosphate

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where are the cell inclusion found and what are their functions

glycogen: found in many species, carbon and energy storage
polyphosphate: found in many species, phosphate storage

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are endospores mainly gram pos or gram neg

main gram pos

just recently found one gram neg one

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what is the importance of endospores

they shut down protein, enzymatic, and macromolecular synthesis and wait

they are important for heat, chemical, and radiation resistance for bacteria

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what are the three locations for bacterial cell in endospores

terminal - all the way to one end
central - in the middle
subterminal - almost all the way to one end

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name the endospore formers

c. difficile
c. botulinum
c. tetani
b. cereus

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what is so important about c. difficile

significant for infection control

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describe sporulation and germination

in harsh environment, bacteria cells undergoes sporulation where it replicates and produces a spore while the original cell dies (take 6-8hrs)

then in favorable environment, the spore germinates back to bacteria taking 1 - 2 hrs

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what are components that influence growth of microorganism

temperature, pH, water, carbon and energy sources, trace elements

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how does temperature influence growth rate of microorganism

there is an optimum range for microorganism growth

also there is a min and max temp where microorganism do not grow

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name the temperature categories in which microorganisms fall under; what the optimum temp is in degree celsius; and if medically significant

psychrotrophs and psychrophiles - 15 oC - No
Mesophiles - 20-40 oC - Yes
thermophiles - 50-60 oC - No

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what is the difference between pyschrotrophs and psychrophiles

psychrophiles are cold loving and actually handle temperatures as low as 2 - 3 oC while psychrotrophs can tolerate the cold weather so their optimum is only 15 oC

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random pop quiz: what is a firmly attached polysaccharide layer that is located external to the cell wall/outer membrane which enables bacterial evasion one of the host non specific defenses

capsule

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list the pH categories in which microorganisms fall under and what pH they can handle

extreme acidophiles: 0-2
acidophiles: 3 - 5
neutrophiles: 6 -8
alkalophiles: 9 - 11
extreme alkalophiles: 12-14

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list the ranges of water availability in which microorganisms can thrive/not thrive

.93 - .98: no growth of gram positive bacteria
.97 - no growth of gram neg bacteria
less than .93 - most spoilage due to yeast and fungi
less than .9 - most bacterial unable to grow
less than .6 - no microbial growth

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what do all organisms need

carbon and energy source

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what are way in which organisms can get energy

chemotrophs - chemical energy

phototrophs - light energy

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examples of phototrophs

plants, algae, photosynthetic bacteria

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what are two types of chemotrophs

chemolithotrophs - use inorganic sources of carbon

chemoorganotrophs (heterotrophs) - use organic sources of carbon (most bacteria)

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examples of chemoorganotrophs aka heterotrophs

bacteria, fungi, protozoa, humans

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what sources can you get the following elements from: carbon, oxygen, nitrogen, hydrogen, phosphorus, sulfur

carbon (50%) - cellular material
oxygen (20%) - cell material and cell water, 02 is an electron acceptor in aerobic respiration
nitrogen - AA, nucleic acid nucleotides, coenzymes
hydrogen - organic compounds and water
phosphorus - nucleic acids, nucleotides, phospholipids, LPS, techoic acid
sulfur - glutathione, cysteine, methionine, several coenzymes

what are trace elements usually needed by microorganisms

usually metal ions - zinc cobalt for ex
enzymes needed in energy generation
organic growth factors like vitamins and minerals

do all microorganisms need organic growth factors

no some of them synthesize their own

what pathogen requires nicotinamide

bordetella pertussis

what pathogen requires X and V factor

haemophilus sp.

in an unshaken culture, describe where each type of microorganisms in relation to their oxygen requirements

top only - obligate aerobes evenly distributed - facultative anaerobe and aerotolerant anaerobe slightly below surface - microaerophile

what is difference between facultative anaerobe and aerotolerant anaerobe

facultative - use O2 if present but if not will use something else aerotolerant - indifferent to O2, even in their presence they won't use them, need non O2 requirements

what are obligate anaerobes and why are they not present in the unshaken cultures

they must be in an area without any oxygen or they will not grow not in unshaken culture because they only grow in specially prepared media/conditions

which group of microorganisms use catalase and superoxide dismutase

obligate aerobes and most facultative anaerobes

which group of microorganisms use only superoxide dismutase

most aerotolerant anaerobes

which group of microorganisms use neither catalase or superoxide dismutase

obligate anaerobes

what is the catalase test and what does it show?

place a few drops of peroxide onto a glass then mix in a loopful of single colony then what for immediate fizzing if bubbles = positive catalase test it shows that O2 is present in colony and that colony must be obligate aerobes or facultative anaerobes

binary fission continues until what happens

the nutrients have been exhausted and conditions become unfavorable

name the generation for the amount of cells listed 2 cells 8 cells 16 cells 64 cells

``` 2 = 1st generation 8 = 3rd generation 16 = 4th generation 64 = 6th generation ```

describe the growth curve

in a closed system, first there is the lag phase where the cells are adapting to their environment then there's the log phase, where the cells increase exponentially then there's the stationary phase where the nutrients are starting to run out and the number of new cells = the new of cell dying then there's death where there is decreasing amounts of viable cells

what is finite in relation to the growth curve

nutrients and space; no waste products removed

what is serial dilutions

case where the original culture is diluted serially until it is possible to count the amount of culture on the plate

what is the equation to figure out the number of bacteria in the original sample

dilution sampled (positive) * volume of liquid in which the sample was taken out of * # visible colonies after dilution

􏰇 # of visible colonies after incubation = 40 􏰇 Dilution sampled = 10^-3 􏰇 Volume of sample plates = 0.1 mL what is the number of bacteria in the original sample

40 * 10^3 * 10 = 400,000 CFU/mL

Calculate the CFU per mL of the original bacterial or fungal culture using the data provided: 42 colonies from 0.1ml plated of 10^-3 dilution

42 * 10 * 10 ^3 = 420,000 CFU/mL

Calculate the CFU per mL of the original bacterial or fungal culture using the data provided: 37 colonies from 0.25ml plated of 10^-6 dilution

37 * 10^6 * 4 = 1.48 * 10^8

what type of graphs are preferred for more accurate cell numbers during growth

logarithmic graphs

what equations are used to calculate generation time

``` n = Log N‐ Log No /0.301 g = t/n ``` ``` where N = total population No = initial population t = time g = generation time n = number of generations ```

what is the importance of generation time

it tells the incubation period and how long until one starts to see symptoms

Calculate the generation time (g) using the following data No = 1.2 x 10^3; N = 3.8 x 10^9; t = 420minutes

n = (9.58 - 3.08)/ .301 = 22 g = 420/22 = 19

to culture media, what three things need to be know

physical state, composition, function/purpose

what are two types of composition

synthetic/defined - where all the components are known complex/non synthetic - where the components are vague

when will you use TSB and what are the components

general purpose macronutrients, micronutrients, carbon source

when will you use blood agar and BCYE agar and what are the components

enrichment general purpose plus blood, serum, antibiotics

when will you use MacConkeys and what are the components

selection and differentiation salts, dyes (brilliant green), antibiotics SAD DSM

when will you use Stuart's media and what are the components

transportation buffers, no nutrients/carbon source

when will you use Mueller Hinton Agar and what are the components

assay eg. antibiotic sensitivity carefully defined formula