Chapter3 Flashcards

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1
Q

Physical requirements – Temperature

“can grow at 0°C but optimum is about 15°C”

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

A

Psychrophiles

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2
Q

Physical requirements – Temperature

“can grow at 0°C also but optimum is 20 - 30°C”

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

A

Psychotrophs

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3
Q

Physical requirements – Temperature

“grow best at moderate around 37°C (many pathogenic microorganisms)”

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

A

Mesophiles

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4
Q

Physical requirements – Temperature

“have a growth optimum at around 60°C”

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

A

Thermophiles

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5
Q

Physical requirements – Temperature

“have growth optimum of 80°C or higher (archaea)”

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

A

Hyperthermophiles

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6
Q

Physical requirements – pH

Most bacteria grow best at pH value between

2-3.5
7-9
3.5-6
6.5-7.5

A

6.5-7.5

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7
Q

Physical requirements – pH

organisms that grow best at low pH (as low as pH 1)?

Acidophiles

Alkaliphiles

A

Acidophiles

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8
Q

Physical requirements – pH

organisms that grow best at high pH (as high as pH 10) (archaebacteria)?

Acidophiles

Alkaliphiles

A

Alkaliphiles

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9
Q

Bacterial growth Physical requirements – Salt

specific requirement for the sodium ion ,need salt to grow?

Halophiles
Halotolerant
Osmophiles
Xerophiles

A

Halophiles

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10
Q

Bacterial growth Physical requirements – Salt

grow best in the absence of NaCl, but can tolerate some NaCl ,no need for salt to grow?

Halophiles
Osmophiles
Halotolerant
Xerophiles

A

Halotolerant

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11
Q

Physical requirements

are able to live in environments high in sugar?

Halophiles
Osmophiles
Halotolerant
Xerophiles

A

Osmophiles

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12
Q

Physical requirements

are able to grow in very dry environments?

Halophiles
Osmophiles
Halotolerant
Xerophiles

A

Xerophiles

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13
Q

the most commonly needed growth factors?

Vitamins
amino acids
purines
pyrimidines

A

Vitamins

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14
Q

Chemical requirements:

-The major element in all classes of macromolecules
-A typical cell is about 50%………

Carbon
Nitrogen
Oxygen
Iron

A

Carbon

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15
Q

Chemical requirements:

-A typical bacterial cell is about 12%………
-Important element in proteins, nucleic acids,…

Carbon
Nitrogen
Oxygen
Iron

A

Nitrogen

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16
Q

Chemical requirements – Oxygen:

“grow on the top of the tube in order to absorb maximal amount of O2 for survival”

•Aerobic bacteria
•Microaerophilic bacteria
•Facultative anaerobic bacteria
•Aerotolerant anaerobic bacteria
•Obligate anaerobic bacteria

A

Aerobic bacteria

17
Q

Chemical requirements – Oxygen:

“grow just below surface as they require O2 at low concentration. They are sensitive to O2 -derived free radicals.”

•Aerobic bacteria
•Microaerophilic bacteria
•Facultative anaerobic bacteria
•Aerotolerant anaerobic bacteria
•Obligate anaerobic bacteria

A

Microaerophilic bacteria

18
Q

Chemical requirements – Oxygen:

“grow throughout the tube”

•Aerobic bacteria
•Microaerophilic bacteria
•Facultative anaerobic bacteria
•Aerotolerant anaerobic bacteria
•Obligate anaerobic bacteriac

A

Facultative anaerobic bacteria

19
Q

Chemical requirements – Oxygen:

“cannot use O2 for growth but also are not affected by it and able to survive in the presence of some O2. So, they can spread a little bit upward from the bottom of the test tube.”

•Aerobic bacteria
•Microaerophilic bacteria
•Facultative anaerobic bacteria
•Aerotolerant anaerobic bacteria
•Obligate anaerobic bacteria

A

Aerotolerant anaerobic bacteria

20
Q

Chemical requirements – Oxygen:

“cannot use O2 for growth and are even harmed by it. So, they grow at the bottom in order to avoid O2”

•Aerobic bacteria
•Microaerophilic bacteria
•Facultative anaerobic bacteria
•Aerotolerant anaerobic bacteria
•Obligate anaerobic bacteria

A

Obligate anaerobic bacteria

21
Q

Chemical requirements – Oxygen:

Which of the following must have superoxide dismutase and catalase enzyme to avoid toxic O2 radicals?

•Aerobic bacteria
•Microaerophilic bacteria
•Facultative anaerobic bacteria
•Aerotolerant anaerobic bacteria
•Obligate anaerobic bacteria

A

All except Obligate anaerobic bacteria

22
Q

Which of the following media do not have agar?

Liquid media
Semi-liquid media
Semi-solid media
Solid media

A

Liquid media

23
Q

Bacterial growth in solid culture is observed as…………?

colony formation

turbidity

A

colony formation

24
Q

Bacterial growth in liquid culture is observed as………?

colony formation

turbidity

A

turbidity

25
Q

-Peptone (provides vitamins and minerals)
-Beef extract (supplies energy, C, N and S)
-Sodium chloride
-Agar
-Water

are:

A

Nutrient broth and agar

26
Q

Simple agar nutrient with blood are?

A

Blood agar

27
Q

“supress unwanted microbes; encourage desired microbes”

Selective media
Differential media
Enrichment media
Selective and differentiative media

A

Selective media

28
Q

“differentiate the colonies of desired microbes from others”

Selective media
Differential media
Enrichment media
Selective and differentiative media

A

Differential media

29
Q

“ increase the numbers of desired microbes to detectable levels”

Selective media
Differential media
Enrichment media
Selective and differentiative media

A

Enrichment media

30
Q

Endo agar, EMB agar and MacConkey agar:
Selective and differentiative media

Selective for Gram-…………bacteria (suppress Gram-…………bacteria)

A

Negative-positive

31
Q

Endo agar, EMB agar and MacConkey agar:
Selective and differentiative media

Differentiative for…………… bacteria
(Lactose (+) bacteria produce colourful colonies)

A

lactose-fermenting

32
Q

Order of the Phases of growth:

1-Lag phase
2-Stationary phase
3-Death phase
4-Log (exponential) phase

A

1-4-2-3

33
Q

-No change in the number of cells; metabolic activity is high
-DNA and enzyme synthesis occurs

The correct phase is:

• Lag phase
• Log (exponential) phase
• Stationary phase
• Death phase

A

Lag phase

34
Q

-Bacteria multiply at the fastest rate (under
the optimal conditions
-Logarithmic or exponential increase in population

The correct phase is:

• Lag phase
• Log (exponential) phase
• Stationary phase
• Death phase

A

Log phase

35
Q

-Equilibrium between cell division and death
-Nutrients are exhausted and waste products build up; pH increases

The correct phase is:

• Lag phase
• Log (exponential) phase
• Stationary phase
• Death phase

A

Stationary phase

36
Q

-The number of deaths exceeds the number of new cells formed
-Population decreases at a logarithmic rate

The correct phase is:

• Lag phase
• Log (exponential) phase
• Stationary phase
• Death phase

A

Death phase

37
Q

Which of the following statements regarding the oxygen requirement of bacteria is not correct?
a. Facultative anaerobic bacteria grow at the bottom of the test tube.
b. Aerotolerant anaerobic bacteria conta n superox de dismutase and catalase enzymes.
c. Microaerophilic bacteria are sensitive to oxygen derived free radicals.
d. Aerobic bacteria grow at the top of the test tube
e. Obligate anaerobic bacteria are harmed by oxygen

A

a