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Cellbio > bacteria cell division part 3 > Flashcards

bacteria cell division part 3 Flashcards

1
Q

calculate pH

A

pH=-log{H+}

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2
Q

what pH do most microbes love

A

6-8

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3
Q

acidophiles vs alkaphiles

A

acid less than 7

alk more than 7

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4
Q

neutralophiles

A

love neutral pH

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5
Q

What helps acid and alkaphiles live in their environment

A

membrane adaptations

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6
Q

Minimum growth temperature

A

decreases membrane fluidity

decrease enzyme activity

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7
Q

maximum growth temperature

A

increase membrane fluidity
membrane collapses
proteins denature (enzymes)
see slide 18 picture

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8
Q

Requires O2 for growth

A

Obligate aerobe

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9
Q

O2 not required but grows better with it

A

Facultative anaerobe

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10
Q

requires low amounts of oxygen for growth

A

Microaerophile

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11
Q

Not killed by O2

A

Aerotolerant anaerobe (SOD but no catalse)

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12
Q

Killed by O2

A

Obligate anaerobe (strict), no enzymes SOD, catalase

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13
Q

where does growth occur in test tube

A

more oxygen needed towards the top

less needed towards bottom

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14
Q 
Organisms that do not require oxygen for growth but grow better in its presence are called \_\_\_\_\_\_\_\_.
A) facultative anaerobes
B) microaerophiles
C) aerotolerant
D) anoxygenic
A

A) facultative anaerobes

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15
Q 
Organisms that ignore oxygen and grow equally well in its presence or absence are called \_\_\_\_\_\_\_\_.
A) facultative anaerobes
B) microaerophiles
C) aerotolerant
D) anoxygenic
A

C)aerotolerant

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16
Q 
Organisms that are damaged by the normal atmospheric levels of oxygen (20%) but require oxygen at levels of 2–10% for growth are called \_\_\_\_\_\_\_\_.
A) facultative anaerobes
B) microaerophiles
C) aerotolerant
D) anoxygenic
A

B) microaerophiles

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17
Q 
Organisms that grow in mud under relatively nonturbulent bodies of water are likely to be \_\_\_\_\_\_\_\_.
A) obligate aerobes
B) thermophilic
C) barophilic
D) anaerobes
A

D) anaerobes

no oxygen under mud

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18
Q

obligate anaerobes are usually poisoned by molecular oxygen but may grow in aerobic habitats if associated with facultative anaerobes that use up all available oxygen.

A

true

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19
Q

Aerotolerant anaerobes ________.
A) synthesize superoxide dismutase, but not catalase
B) synthesize both superoxide dismutase and catalase
C) synthesize neither superoxide dismutase nor catalase
D) synthesize catalase but not superoxide dismutase

A

A) synthesize superoxide dismutase, but not catalase

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20
Q

Reactive oxygen species

A

Produced during aerobic respiration
Enzymes to destroy toxic reactive oxygen species
Have all, some or no enzymes

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21
Q

Which reactive oxygen species have all enzymes

A

Obligate aerobes, facultative anaerobes

have SOD, catalase

22
Q

which reactive oxygen species Produced during aerobic respiration

A

Superoxide and hydroxyl radicals; H2O2

Damage cell components

23
Q

which reactive oxygen species has some enzymes

A

Microaerophiles; aerotolerant anaerobes

24
Q

which reactive oxygen species has no enzymes usually

A

Obligate (strict) anaerobes
Exception: some obligate anaerobes may have superoxide reductase
have sod might have catalase

25
Q

Facultative anaerobes differ from aerotolerant anaerobes in that ________.

look at both

A

A) facultative anaerobes synthesize both superoxide dismutase and catalase for protection against reactive oxygen species (ROS), whereas aerotolerant anaerobes synthesize superoxide dismutase only, allowing survival in the presence of ROS, but they do not utilize O2 in their metabolic pathways

26
Q

How to culture anaerobes

A

need to remove and exclude oxygen

27
Q

How to remove or exclude oxygen

A

Special reducing agent (eliminate O2 in media)

Anaerobic chamber

28
Q

Capnophiles

A

require high CO2 for growth

29
Q

Exponential growth (log scale)

A

of cells doubles during fixed time

30
Q

arithmetic plot

A

cell number vs time

linear

31
Q

semilogarithmic plot (see slide 23)

A

cell number vs time

32
Q

Exponential growth

A

N1=N0 x 2^N

33
Q

exponents of exponential growth

A

N1= final cell #
No= initial cell #
2=cell doubles (constant #)
n= # generations

34
Q 
Microorganisms are at their most uniform in terms of chemical and physiological properties during \_\_\_\_\_\_\_\_ phase.
A) lag
B) exponential
C) stationary
D) decline
A

B) exponential

see slide 25

35
Q

lag phase

A

repairing damage, cell making components

36
Q

log (exponential) phase

A

actively growing cells

37
Q

what affects log phase

A

temp, media, genetics

38
Q

Stationary phase

A

no net increase or decrease in number of cells

nutrients used up and waste builds up

39
Q

death phase

A

exponential decline

cells die constant rate

40
Q

how do resistant cells arise

A

from long stationary phase

41
Q

One of the major advantages of a continuous culture system is that the cells can be maintained in the exponential growth phase for extended periods of time.

A

True

42
Q 
Which of the following are a reason(s) for the decline in cell numbers during the death phase?
A) Depletion of nutrients
B) Accumulation of toxic waste materials
C) Depletion of O2
D) All of the choices are correct.
A

D) all choices

43
Q

One hypothesis about the decline in cell numbers during death phase is that the cells aren’t all dying but instead remain alive but unable to grow when cultured, at least temporarily. These are known as ________.

A

A) viable but nonculturable cells

44
Q

A microbiologist is studying the growth of a particular strain of bacteria to determine when it will transition from exponential growth to stationary phase and from stationary phase to death phase. Which of the following methods of measuring microbial growth would be best for this purpose?

A

viable plate count

45
Q

The total number of viable microorganisms remains constant in stationary phase because ________.

A

C) either there is a balance between cell division and cell death or
there is a cessation of cell division even though the cells may remain metabolically active

46
Q

Cells may enter stationary phase because of ________.
A) the depletion of an essential nutrient
B) a lack of available oxygen
C) the accumulation of toxic waste products
D) All of the choices are correct.

A

D) all choices are correct

47
Q 
Microorganisms are at their most uniform in terms of chemical and physiological properties during \_\_\_\_\_\_\_\_ phase.
A) lag
B) exponential
C) stationary
D) decline
A

B) exponential

48
Q

Which of the following is a reason for the occurrence of a lag phase in a bacterial growth curve?
A) The cells may be old and depleted of ATP, essential cofactors, and ribosomes that must be synthesized before growth can begin.
B) The medium may be different from the previous growth medium so that the cells must synthesize new enzymes to use different nutrients.
C) The organisms may have been injured and require time to recover.
D) All of these are potential reasons.

A

D) All of these are potential reasons.

49
Q

During the lag phase of microbial growth, the cells are metabolically inactive.

A

False, they are repairing and making parts

50
Q 
The length of the lag phase of growth can vary depending on \_\_\_\_\_\_\_\_.
A) the condition of the microorganisms
B) the nature of the growth medium
C) the temperature
D) All of the choices are correct.
A

D) all choices are correct

Cellbio (17 decks)

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