MCQs Microbiology ::Nutrition of Bacteria

1.
A synergistic effect is observed when

A. one organism removes an inhibitory substance for another
B. one organism produces a growth factor utilized by another
C. microbial alteration of pH, aw, Eh favours the growth of another
D. all of the above
Answer & Explanation
Answer: Option D

2.
Generation time is

A. time required for the population to double
B. time required for the initial adjustment
C. obtained by expression t/n, where t = time interval, n = number of generation
D. both (a) and (c)
Answer & Explanation
Answer: Option D

3.
The term facultative anaerobe refers to an organism that

A. doesn't use oxygen but tolerates it
B. is killed by oxygen
C. uses oxygen when present or grows without oxygen when absent
D. requires less oxygen than is present in air
Answer & Explanation
Answer: Option C

4.
The microorganisms that grow best in a low-oxygen environment is called a (n)

A. aerobe B. anaerobe
C. facultative D. microaerophile
Answer & Explanation
Answer: Option D

5.
Pseudomonas pseudoflava can grow as

A. chemo-lithotrophs
B. chemo-organotrophs
C. both (a) and (b)
D. none of these
Answer & Explanation
Answer: Option C

6.
Which of the following is the suitable temperature range for mesophiles?

A. 20-30°C
B. 25-40°C
C. >40°C
D. None of these
Answer & Explanation
Answer: Option B

7.
Exponential phase of growth curve of bacteria is of limited duration because of

A. rise in cell density
B. accumulation of toxic metabolites
C. exhaustion of nutrients
D. all of these
Answer & Explanation
Answer: Option D

8.
A culture broth tube was very turbid at the bottom of the tube but clear at the top of the tube indicating that the

A. broth is sterile
B. organism can tolerate oxygen
C. organism cannot produce superoxide dismutase and/or catalase
D. organism should be grown in an anaerobic chamber
Answer & Explanation
Answer: Option C

9.
In the exponential phase, the cells and cell mass

A. first increases then decreases
B. decreases
C. are constant
D. double at a constant rate
Answer & Explanation
Answer: Option D

10.
What is the primary source of food for marine life?

A. Phytoplankton
B. Zooplankton
C. Sea weed
D. Grass
Answer & Explanation
Answer: Option A

11.
Postgates assay technique is useful in determining if a cell is viable even though it is

A. incapable of cell division
B. too small to see
C. an obligate aerobe
D. a thermophile
Answer & Explanation
Answer: Option A

12.
What are the extrinsic factors for the microbial growth?

A. humidity
B. storage temperature
C. composition of gas phase
D. all of these
Answer & Explanation
Answer: Option D

13.
Quantitative measurement of bacterial growth can be carried out by measuring

A. cell count
B. cell mass
C. cell activity
D. all of these
Answer & Explanation
Answer: Option D

14.
3.
Quantitative measurement of bacterial growth can be carried out by measuring

A. cell count
B. cell mass
C. cell activity
D. all of these
Answer & Explanation
Answer: Option D

15.
The combination of low levels of NaCl, NaNO3 (sodium nitrate), and slightly acid pH can prevent multiplication and toxin formation of

A. Salmonella
B. S. aureus
C. C. botulinum
D. all of these
Answer & Explanation
Answer: Option D

16.
Bacteria of genus Nitrosomonas use __________ as their electron source.

A. ammonia B. H2S
C. succinate D. light
Answer & Explanation
Answer: Option A

17.

All organisms require at least small amounts of carbondioxide, However, some can use CO2 as their sole source of carbon. Such organisms are termed as

A. autotrophs B. phototrophs
C. chemotrophs D. photo-organotrophs
Answer & Explanation
Answer: Option A

18.

The generation time of a culture that produces two generations per hour is

A. greater than that produces three generations per hour
B. lesser than that produces three generations per hour
C. equal to that produces three generations per hour
D. none of the above
Answer & Explanation
Answer: Option A

Explanation:

19.

Autotrophic bacteria are those which

A. make their own food
B. form a long chain glycocalyx
C. are highly susceptible to penicillin
D. produce a blue-green pigment
Answer & Explanation
Answer: Option A

20.
Which of the following organisms typically get their carbon for biosynthesis from organic compounds?

A. Aerobic, glucose-respiring bacteria (aerobic respiration)
B. Ammonia-oxidizing bacteria (chemolithotrophic bacteria)
C. Photosynthetic cyanobacteria (phototrophic metabolism)
D. None of the above
Answer & Explanation
Answer: Option A

21.
An organism is completely dependent on atmospheric O2 for growth. This organism is

A. osmotolerant
B. acidophile
C. facultative anaerobe
D. obligate aerobe
Answer & Explanation
Answer: Option D

22.

Microaerophilic bacteria are those which require

A. 21 % oxygen for growth
B. low levels of oxygen for growth (lesser than O2 present in atmosphere)
C. oxygen for activation of enzymes
D. none of the above
Answer & Explanation
Answer: Option B

23.

The period between inoculation of bacteria in a culture medium and beginning of multiplication is known as

A. stationary phase
B. log phase
C. lag phase
D. decline phase
Answer & Explanation
Answer: Option C

24.
The term aerotolerant anaerobe refers to an organism that

A. doesn't use oxygen but can grow in the presence of oxygen
B. is killed by oxygen
C. requires less oxygen than is present in air
D. prefers to grow without oxygen
Answer & Explanation
Answer: Option A

25.
The term obligate anaerobe refers to an organism that

A. doesn't use oxygen but tolerates it
B. is killed by oxygen
C. uses oxygen when present or grows without oxygen when oxygen is absent
D. prefers to grow without oxygen
Answer & Explanation
Answer: Option B

26.
The fragmentation occurs in

A. Streptomyces species
B. Nocardia species
C. Bacillus subtilis
D. None of these
Answer & Explanation
Answer: Option B