Estimating Bacterial Count Flashcards

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1
Q

computation of CFU

A

colony forming unit

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2
Q

represent particular cell that have dividing capabilities

A

colony forming unit

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3
Q

unit that we use for estimating the number of viable bacteria or the fungal cells in a sample

A

colony forming unit

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4
Q

asexual reproduction by a separation of the body into two new bodies

A

binary fission

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5
Q

– viable cells being computed utilizing hemocytometer

A

direct count

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6
Q

increase in the number of cells

A

microbial growth

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7
Q

 Depends on the nutrients of culture medium and the environmental requirements of the microorganisms

A

microbial growth

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8
Q

parts of a growth curve

A

lag phase
log (exponential) phase
stationary phase
death (decline) phase

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9
Q

introduction of microorganism to the culture medium

A

lag phase

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10
Q

– phase where microorganisms increasese

A

exponential phase (log)

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11
Q

phase where microorganisms reach their carrying capacity

A

stationary phase

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12
Q

natural occurrence where organisms fight for limited resources

A

competition

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13
Q

– represent that resources on the environment has been depleted

A

death phase

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14
Q

general media used previously in midterms

A

nutrient agar

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15
Q

time of gearing up for division following change in culture conditions

A

lag phase

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16
Q

 Introduction of microbes in the environment

A

lag phase

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17
Q

division at a constant rate (exponential)

A

log or exponential phase

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18
Q

death rate = birth rate

A

stationary phase

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19
Q

 Represents the carrying capacity of the environment

A

stationary phase

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20
Q

 Shows the max number of microbes

A

stationary phase

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21
Q

– constant per-capita death rate (exponential

A

death phase

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22
Q

 Represents the competition

A

death phase

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23
Q

used to determine how microorganisms grow, assess the foods and monitor industrial processes

A

microbial counts

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24
Q

 An indicator of spoilage

A

microbial counts

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25
Q

process through which the concentration of an organisms (ex. Bacteria) is systematically reduced through successive resuspension in fixed volumes of liquid diluent.

A

serial dilution

26
Q

 Usually the volume of __ is a multiple of 10 to facilitate logarithmic reduction of the sample organism

A

diluent

27
Q

a substance used to dilute something.

A

diluent

28
Q

counting methods (3)

A

direct count
pour plate method (viable count)
spread plate method (viable count)

29
Q

counting methods for viable counting

A

pour plate method
spread plate method

30
Q

– include microscopic counts using a hemocytometer or a counting chamber

A

direct count

31
Q

 Dead cells are also counted

A

direct count

32
Q

technique when counting for direct count

A

L rule

33
Q

The central square is further subdivided into 0.05 x 0.05 mm (0.0025 mm2) squares.

A

nunbauer ruling

34
Q

is a tool used for manual cell countin

A

hemocytometer

35
Q

what quadrants are counted in hemocytometer

A

1, 5, 13, 21,25

36
Q

formula for direct count

cells/mm^2

A

number of cells in 5 squares * 5

37
Q

formula for direct count

cells/mm^3

A

cells/mm^2 *10

38
Q

cells / ml formula

A

cells /mm^3 x 1000

39
Q

dilution factor in computation

A

10^4

40
Q

formula for direct counting

A

(number of cells in 5 squares)(10)(1000)(DF)

41
Q

method used in cell culture to determine the number of living cells in a culture

A

viable count/plate count

42
Q

 This is different from other cell counting techniques because it makes a distinction between live and dead cells

A

viable count/plate count

43
Q

 Colony forming units are only considered

A

viable count

44
Q

consist of diluting a sample with sterile saline or phosphate buffer diluent until the bacteria are dilute enough to count accurately

A

standard plate count method

45
Q

– should have between 30 and 300 colonies

A

final plates

46
Q

– not acceptable for statistical reasons

A

<30

47
Q

<30 means

A

too few to count

48
Q

colonies too close to each other to be distinguished as distinct colony forming units

A

> 300

49
Q

TNTC means

A

Too numerous to count

50
Q

view different number of colonies in ppt

A

+1

51
Q

an equipment that is designed to assist you when counting colonies on agar plates

A

colony counter

52
Q

colony counting can be done via (3)

A

pushbutton
pen probe
needle probe

53
Q

To look through the viewing area to assist with the counting of smaller colonies

A

magnifying glass

54
Q

A glass viewing area with a grid pattern drawn on it and a light to illuminate the agar plate.

A

ruled counting area

55
Q

pour plate method amount of innoculum

A

1.0ml

56
Q

spread plate method amount of innoculum

A

0.1mL

57
Q

formula for viable counting

A

(no of colonies)(total dilution factor)/volume of culture plated in ml

58
Q

what part of the growth curve represent the increase in population of certain organisms

A

log (exponential) phase

59
Q

loss of resources in a culture media

what part of a growth curve

A

stationary phase or death (decline) phase

60
Q

which represents competition among organisms in growth chart

A

stationary phase