bacterial culture growth curve Flashcards

1
Q

observed when microbes are cultivated in batch culture=

A

closed vessel, limited nutrients

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2
Q

usually plotted as

A

logarithm of cell number vs time

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3
Q

has 4 phases

A

Lag

Exponential (Log)

Stationary

Death (Decline)

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4
Q

Lag phase

A

no increase in cell numbers

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5
Q

Exponential (Log)

A

maximal rate of division and population growth

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6
Q

Stationary

A

population growth ceases - death rate = division

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7
Q

death (decline)

A

population number decreases

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8
Q

in the LAG PHASE cells are

A

synthesizing new components

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9
Q

in the LAG PHASE cells are preparing for

A

exponential phase (dedicated growth)

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10
Q

in the LAG PHASE cells are replenishing

A

spent materials, making new ones

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11
Q

in the LAG PHASE cells are adapting to

A

new medium or other conditions

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12
Q

in the LAG PHASE cells are repairing

A

damage

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13
Q

the LAG PHASE varies in

A

length (can be so short, its undectable)

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14
Q

exponential phase aka

A

log phase

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15
Q

in the EXPONENTIAL PHASE (LOG) rate of growth is

A

constant

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16
Q

in the EXPONENTIAL PHASE (LOG) the population is most

A

uniform in terms of chemical & physical properties

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17
Q

in the EXPONENTIAL PHASE (LOG) all cells are dedicated to

A

growth

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18
Q

in the EXPONENTIAL PHASE (LOG) bacteria are MOST

A

susceptible to antibiotics

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19
Q

in the STATIONARY PHASE total number of

A

viable cells remans constant

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20
Q

in the STATIONARY PHASE no net growth in number of cells because

A

reproductive rate equals death rate

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21
Q

in the STATIONARY PHASE as many cells dying as being

A

replicated

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22
Q

in the STATIONARY PHASE cells are changing to become more

A

resistant to harsh conditions

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23
Q

in the STATIONARY PHASE bacteria are MOST

A

resistant to antimicrobials

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24
Q

why enter stationary phase?

A

inhospitable environement

low nutrients/O2
high wastes or population density

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25
Q

starvation response adaptations in the STATIONARY PHASE

A

morphological changes

production of starvation proteins

production of secondary metabolities including antibiotics & antimicrobial compounds

can lead to increased virulence

26
Q

what are the morphological changes in starvation response adaptations

A

endospore formation

decrease in size

condense the nucleoid

27
Q

in the DEATH PHASE, why do cells die?

A

limited nutrients

buildup of toxic wastes

28
Q

in the DEATH PHASE cells are viable but not

A

culturable

29
Q

in the DEATH PHASE many cells undergo programmed

A

apoptosis (cell death)

30
Q

what are the 2 categories for cell growth

A

physical and chemical

31
Q

what are physical requirements for cell growth

A

temp

pH change

osmotic pressure

32
Q

what are chemical requirements for cell growth

A

carbon

nitrogen, sulfur, phosphorous

trace elements

organic growth factors

oxygen availability

33
Q

optimal temp definition

A

is the temp at which a procedure is best carries out

34
Q

cardinal groups definition

A

based on the optimal temp range for organism’s growth

35
Q

what are the cardinal groups

A

psychrophiles

psychrotrophs

mesophiles

thermophiles

hyperthermophiles

36
Q

thermophiles optimal temp:

A

60-65 degrees C

37
Q

hyperthermophiles optimal temp:

A

75-80 degrees C

38
Q

mesophiles optimal temp:

A

35-40 degrees C

39
Q

psychrotrophs optimal temp:

A

25-30 degrees C

40
Q

psychrophiles optimal temp:

A

10-15 degrees C

41
Q

what are the pH cardinal groups

A

acidophiles

neutrophiles

alkalophiles

42
Q

alkalophiles optimal pH

A

8.5-11.5

43
Q

acidophiles optimal pH

A

1-5.5

44
Q

neutrophiles optimal pH

A

5.5-7

45
Q

neutrophiles optimal pH

A

5.5-7

46
Q

cellular pH regulation

A

some synthesize special proteins that provide protection from toxic pHs

change pH of their habitat by producing acidic or basic waste products

47
Q

osmotic pressure cardinal groups

A

extreme/obligate halophiles

facultative halophiles

48
Q

extreme/obligate halophiles optimal concentration of salt

A

above 30% NaCl

49
Q

facultative halophiles optimal concentration of salt

A

2& NaCl

50
Q

what phases are heterogeneous

A

lag

stationary

51
Q

what phase is homogeneous

A

exponential (Log)

52
Q

what phase is most susceptible to antimicrobials

A

Exponential (Log) Phase

53
Q

what phase is Most resistant to antimicrobials

A

Stationary Phase

54
Q

what phase Beginning to produce endospores (if applicable)

A

Stationary Phase

55
Q

What are some characteristics and observations that can be made of cells in the stationary phase?

A

The total number of viable cells remains constant because reproductive rates equals death rate. This means as many cells that are dying as being replicated. Cells begin to change and become more resistant to harsh conditions. The cells go through starvation response this includes: endospore formation, decrease in size, and condensing the nucleoid.

56
Q

which cardinal group make humans sick

A

mesophiles

57
Q

which cardinal groups spoil refrigated groups

A

psychrophiles

psychrotrophs

58
Q

which cardinal group can spoil room temp food

A

psychrotrophs

59
Q

which cardinal group can spoil

refrigated
frozen
but NOT room temp

A

psychrophiles

60
Q

which cardinal group can spoil

refrigated
frozen
room temp

A

psychrotrophs