Chapter3

Question 1

Physical requirements – Temperature

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

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

Answer 1

Psychrophiles

Question 2

Physical requirements – Temperature

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

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

Answer 2

Psychotrophs

Question 3

Physical requirements – Temperature

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

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

Answer 3

Mesophiles

Question 4

Physical requirements – Temperature

“have a growth optimum at around 60°C”

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

Answer 4

Thermophiles

Question 5

Physical requirements – Temperature

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

• Psychrophiles
• Psychotrophs
• Mesophiles
• Thermophiles
• Hyperthermophiles

Answer 5

Hyperthermophiles

Question 6

Physical requirements – pH

Most bacteria grow best at pH value between

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

Answer 6

6.5-7.5

Question 7

Physical requirements – pH

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

Acidophiles

Alkaliphiles

Answer 7

Acidophiles

Question 8

Physical requirements – pH

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

Acidophiles

Alkaliphiles

Answer 8

Alkaliphiles

Question 9

Bacterial growth Physical requirements – Salt

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

Halophiles
Halotolerant
Osmophiles
Xerophiles

Answer 9

Halophiles

Question 10

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

Answer 10

Halotolerant

Question 11

Physical requirements

are able to live in environments high in sugar?

Halophiles
Osmophiles
Halotolerant
Xerophiles

Answer 11

Osmophiles

Question 12

Physical requirements

are able to grow in very dry environments?

Halophiles
Osmophiles
Halotolerant
Xerophiles

Answer 12

Xerophiles

Question 13

the most commonly needed growth factors?

Vitamins
amino acids
purines
pyrimidines

Answer 13

Vitamins

Question 14

Chemical requirements:

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

Carbon
Nitrogen
Oxygen
Iron

Answer 14

Carbon

Question 15

Chemical requirements:

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

Carbon
Nitrogen
Oxygen
Iron

Answer 15

Nitrogen

Question 16

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

Answer 16

Aerobic bacteria

Question 17

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

Answer 17

Microaerophilic bacteria

Question 18

Chemical requirements – Oxygen:

“grow throughout the tube”

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

Answer 18

Facultative anaerobic bacteria

Question 19

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

Answer 19

Aerotolerant anaerobic bacteria

Question 20

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

Answer 20

Obligate anaerobic bacteria

Question 21

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

Answer 21

All except Obligate anaerobic bacteria

Question 22

Which of the following media do not have agar?

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

Answer 22

Liquid media

Question 23

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

colony formation

turbidity

Answer 23

colony formation

Question 24

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

colony formation

turbidity

Answer 24

turbidity

Question 25

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

Answer 25

Nutrient broth and agar

Question 26

Simple agar nutrient with blood are?

Answer 26

Blood agar

Question 27

“supress unwanted microbes; encourage desired microbes” Selective media Differential media Enrichment media Selective and differentiative media

Answer 27

Selective media

Question 28

“differentiate the colonies of desired microbes from others” Selective media Differential media Enrichment media Selective and differentiative media

Answer 28

Differential media

Question 29

“ increase the numbers of desired microbes to detectable levels” Selective media Differential media Enrichment media Selective and differentiative media

Answer 29

Enrichment media

Question 30

Endo agar, EMB agar and MacConkey agar: Selective and differentiative media Selective for Gram-…………bacteria (suppress Gram-…………bacteria)

Answer 30

Negative-positive

Question 31

Endo agar, EMB agar and MacConkey agar: Selective and differentiative media Differentiative for…………… bacteria (Lactose (+) bacteria produce colourful colonies)

Answer 31

lactose-fermenting

Question 32

Order of the Phases of growth: 1-Lag phase 2-Stationary phase 3-Death phase 4-Log (exponential) phase

Answer 32

1-4-2-3

Question 33

-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

Answer 33

Lag phase

Question 34

-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

Answer 34

Log phase

Question 35

-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

Answer 35

Stationary phase

Question 36

-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

Answer 36

Death phase

Question 37

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

Answer 37

a