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MCB 101 Lab > Exercise 4 Quantitative Bacteriology > Flashcards

Exercise 4 Quantitative Bacteriology Flashcards

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1
Q

It is an orderly increase in the quantity of cellular constituents

A

growth

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2
Q

growth is an orderly increase of what?

A

quantity of cellular constituents

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3
Q

The growth of bacteria depends upon the ability of the cell to form ______ ______ from the nutrients available in the environment

A

new protoplasm

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4
Q

this activity of bacteria depends on the ability of the cell wall to form new protoplasm from nutrients available in the environment

A

growth

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5
Q

In most bacteria, growth involves what processes? (6) basically its life cycle

A
  1. increase in cell mass and number of chromosomes 2. duplication of the bacterial chromosomes 3. synthesis of new cell wall and plasma membrane 4. partitioning of the two chromosomes 5. septum formation 6. division of the cell into 2 daughter cells
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6
Q

this type of reproduction of bacteria where there is an increase in cell mass and number of chromosomes, duplication of the bacterial chromosomes, synthesis of new cell wall and plasma membrane, partitioning of the two chromosomes, septum formation, division of the cell into 2 daughter cells

A

binary fission

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7
Q

two daughter cells contain what components?

A

copy of the genome and other vital components

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8
Q

after its division, these cells will contain a copy of the genome and other vital components from its parent cell

A

daughter cells

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9
Q

the parameters used for unicellular organisms when measuring growth

A

changes in cell mass changes in cell numbers

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10
Q

changes in cell mass and cell numbers are parameters used to measure the growth of what organisms?

A

unicellular organisms (e.g bacteria)

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11
Q

methods that can be employed to determine cell numbers

A

Direct or indirect methods

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12
Q

Direct or indirect methods are employed to determine ___ ___ of cultures

A

cell numbers

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13
Q

2 methods that the growth in a population is usually measured quantitatively by

A

plate count and turbidimetric methods

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14
Q

plate count and turbidimetric methods are used to quantitatively measure what?

A

growth in a population

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15
Q

plate count is also known as

A

viable count

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16
Q

viable count is also known as

A

plate count

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17
Q

it is usually done by diluting the original sample, plating aliquots of the dilution into an appropriate culture medium and then incubating the plates under proper conditions to form colonies, after incubation, colonies are counted

A

viable cell count

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18
Q

provide the sequence for viable cell count

A
  1. Diluting the original sample 2. Plating aliquots of the dilutions into an appropriate culture medium 3. incubation of plates under proper conditions 4. counting of colonies
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19
Q

The ideal source of colony in determination of the total number of viable cells

A

one cell

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20
Q

Colony from one cell is used for accurate determination of the total number of ____ ____

A

viable cells

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21
Q

due to the possibility of not being certain that each colony will arise from an individual cell, the results in viable counts are often expressed in terms of ____ ____ ____ rather than the number of microorganisms

A

colony forming units(CFU)

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22
Q

in viable counts, colony forming units (CFU) are expressed rather than ____ __ _____ due to the possibility of not being certain that each colony will arise from an individual cell

A

number of microorganisms

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23
Q

colony forming units (CFU) rather than number of microorganisms are expressed in viable counts because?

A

there is a possibility of not being certain that each colony will arise from an individual cell

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24
Q

this employs a spectrophotometer to measure the turbidity of a suitable liquid medium inoculated with a specified microorganism at a known physiological state of growth

A

turbidimetric method

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25
Q

a device used to measure turbidity of a suitable liquid medium inoculated with microorganism

A

spectrophotometer

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26
Q

what does turbidimetric method measures?

A

turbidity of the liquid medium inoculated with microorganism

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27
Q

a function of microbial cell growth

A

turbidity

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28
Q

turbidity is a function of microbial ____ ____

A

cell growth

29
Q

turbidimetric method is based on the close relationship of what 2 variables?

A

observable turbidity changes in microbial cell numbers

30
Q

establishes the relationship between OD readings and viable counts

A

standard optical density curve

31
Q

standard optical density curve establishes the relationship between

A

OD readings and viable counts

32
Q

What is plotted in the standard optical density curve

A

turbidity of different concentrations of a given species of microorganisms vs number of viable microorganism per ml of sample tested determined by plate count methods

33
Q

turbidity of different concentrations of a given species of microorganisms vs number of viable microorganism per ml of sample tested determined by plate count methods is plotted to generate what curve?

A

standard optical density curve

34
Q

this is used for visual estimation of any given suspension of microorganism

A

turbidimetric standard calibration standard curve

35
Q

turbidimetric calibration standard curve is used for?

A

visual estimation of any given suspension of microorganism

36
Q

What specimen were used in this activity?

A

E coli

37
Q

how old was the E coli during the exercise proper?

A

24-h old

38
Q

what media was utilized for this exercise?

A

Plate count agar (PCA)

39
Q

alternative media that can be utilized in performing this exercise

A

standard methods agar

40
Q

serial diluents utilized for this exercise

A

Distilled water phosphate buffer Peptone water with saline solution

41
Q

concentration of saline solution for the peptone water with saline solution

A

0.0085

42
Q

concentration of peptone water for the peptone water with saline solution

A

0.001

43
Q

diluent used as stock suspension of E coli

A

phosphate buffer

44
Q

final volume of the stock suspension utilized in this exercise

A

15 ml

45
Q

volume of aliquot transferred to plate

A

0.1 ml

46
Q

which dilution was plated in duplicates in this exercise

A

10^-6 and 10^-7 dilutions

47
Q

tool utilized in spreading the aliquot in the plate

A

L-shaped glass rod

48
Q

incubation period for the plates inoculated with the aliquots

A

24-48h

49
Q

valid counts for bacteria

A

25-250 colonies

50
Q

if only one of the dilutions gives valid count what formula is used?

A

with photo attached

51
Q

if two consecutive dilutions gives valid count what formula is used?

A

with photo attached

52
Q

computing for the number of cells per ml at each particular dilution formula

A

with photo attached

53
Q

is the reciprocal of the final dilution

A

dilution factor

54
Q

dilution factor is the _____ of the final dilution

A

reciprocal

55
Q

product of all dilutions used

A

final dilution

56
Q

final dilution is the ____ of all dilutions used

A

product

57
Q

N1 in the formula for two consecutive dilutions is the

A

number of plates in lower dilution counted

58
Q

N2 in the formula for two consecutive dilutions is the

A

number of plates in the next higher dilution counted

59
Q

d in the formula for two consecutive dilutions is the

A

lower dilution

60
Q

the absorbance where OD was read

A

590nm

61
Q

dilution formula

A

with photo attached

62
Q

characteristics of good diluen

A

non toxic readily available easy to prepare free from contaminants stable etc

63
Q

valid values for OD readings to be reported in standard curve

A

0.1 - 0.5 values

64
Q

the x axis of standard curve

A

OD readings

65
Q

the y axis of standard curve

A

number of cells/ml

66
Q

final volume of the diluent utilized in this exercise in the estimation of the cell number by OD determination

A

5ml

67
Q

volume transferred from the stock E coli stock suspension to each of the serial diluents to achieve 10^-2 dilution (final vol of the dram vial 50 mL)

A

0.5 ml

68
Q

volume transferred from the serial diluent to the 1st screw cap with the dilution of 10^-4 (final vol of the tube 10 mL)

A

0.1 ml

69
Q

with the absence of vortex mixer, what needs to be done to properly distribute the culture in the serial diluents?

A

properly shake the tube

MCB 101 Lab (7 decks)

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