Principles of Micro 4 Flashcards

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1
Q

what are the two types of cell inclusions in bacteria

A

glycogen and polyphosphate

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2
Q

where are the cell inclusion found and what are their functions

A

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

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3
Q

are endospores mainly gram pos or gram neg

A

main gram pos

just recently found one gram neg one

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4
Q

what is the importance of endospores

A

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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5
Q

what are the three locations for bacterial cell in endospores

A

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

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6
Q

name the endospore formers

A

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

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7
Q

what is so important about c. difficile

A

significant for infection control

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8
Q

describe sporulation and germination

A

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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9
Q

what are components that influence growth of microorganism

A

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

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10
Q

how does temperature influence growth rate of microorganism

A

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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11
Q

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

A

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

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12
Q

what is the difference between pyschrotrophs and psychrophiles

A

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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13
Q

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

A

capsule

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14
Q

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

A
extreme acidophiles: 0-2
acidophiles: 3 - 5
neutrophiles: 6 -8
alkalophiles: 9 - 11
extreme alkalophiles: 12-14
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15
Q

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

A

.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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16
Q

what do all organisms need

A

carbon and energy source

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17
Q

what are way in which organisms can get energy

A

chemotrophs - chemical energy

phototrophs - light energy

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18
Q

examples of phototrophs

A

plants, algae, photosynthetic bacteria

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19
Q

what are two types of chemotrophs

A

chemolithotrophs - use inorganic sources of carbon

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

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20
Q

examples of chemoorganotrophs aka heterotrophs

A

bacteria, fungi, protozoa, humans

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21
Q

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

A

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

22
Q

what are trace elements usually needed by microorganisms

A

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

23
Q

do all microorganisms need organic growth factors

A

no some of them synthesize their own

24
Q

what pathogen requires nicotinamide

A

bordetella pertussis

25
Q

what pathogen requires X and V factor

A

haemophilus sp.

26
Q

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

A

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

27
Q

what is difference between facultative anaerobe and aerotolerant anaerobe

A

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

28
Q

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

A

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

29
Q

which group of microorganisms use catalase and superoxide dismutase

A

obligate aerobes and most facultative anaerobes

30
Q

which group of microorganisms use only superoxide dismutase

A

most aerotolerant anaerobes

31
Q

which group of microorganisms use neither catalase or superoxide dismutase

A

obligate anaerobes

32
Q

what is the catalase test and what does it show?

A

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

33
Q

binary fission continues until what happens

A

the nutrients have been exhausted and conditions become unfavorable

34
Q

name the generation for the amount of cells listed

2 cells
8 cells
16 cells
64 cells

A
2 = 1st generation
8 = 3rd generation
16 = 4th generation
64 = 6th generation
35
Q

describe the growth curve

A

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

36
Q

what is finite in relation to the growth curve

A

nutrients and space; no waste products removed

37
Q

what is serial dilutions

A

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

38
Q

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

A

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

39
Q

􏰇 # 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

A

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

40
Q

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

A

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

41
Q

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

A

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

42
Q

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

A

logarithmic graphs

43
Q

what equations are used to calculate generation time

A
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
44
Q

what is the importance of generation time

A

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

45
Q

Calculate the generation time (g) using the following data

No = 1.2 x 10^3; N = 3.8 x 10^9; t = 420minutes

A

n = (9.58 - 3.08)/ .301 = 22

g = 420/22 = 19

46
Q

to culture media, what three things need to be know

A

physical state, composition, function/purpose

47
Q

what are two types of composition

A

synthetic/defined - where all the components are known

complex/non synthetic - where the components are vague

48
Q

when will you use TSB and what are the components

A

general purpose

macronutrients, micronutrients, carbon source

49
Q

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

A

enrichment

general purpose plus blood, serum, antibiotics

50
Q

when will you use MacConkeys and what are the components

A

selection and differentiation

salts, dyes (brilliant green), antibiotics

SAD DSM

51
Q

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

A

transportation

buffers, no nutrients/carbon source

52
Q

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

A

assay eg. antibiotic sensitivity

carefully defined formula