MCQOPTIONS
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MCQOPTIONS
This section includes 143 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
The Redfield ratio is an index of concentration of |
| A. | carbon, hydrogen and oxygen |
| B. | nitrogen, potassium and iron |
| C. | carbon, nitrogen and phosphorous |
| D. | carbon, phosphorous and sulfur |
| Answer» D. carbon, phosphorous and sulfur | |
| 52. |
Which of the following conditions decreases the level of denitrification? |
| A. | Abundance of organic matter |
| B. | Acidic pH |
| C. | Elevated temperatures |
| D. | Availability of oxygen |
| Answer» C. Elevated temperatures | |
| 53. |
Which of the following compounds are required for growth of saprophytic bacteria and fungi? |
| A. | organic compounds |
| B. | nitrates |
| C. | phosphates |
| D. | mercury |
| Answer» B. nitrates | |
| 54. |
Which among the following are the most important agents for carbon dioxide fixation? |
| A. | bacteria |
| B. | fungi |
| C. | algae |
| D. | protozoa |
| Answer» D. protozoa | |
| 55. |
Which of the following layer is composed of soft mud or ooze? |
| A. | Photic zone |
| B. | Limnetic zone |
| C. | Benthic zone |
| D. | Profundal zone |
| Answer» D. Profundal zone | |
| 56. |
Which of the following organisms are known to grow on the surfaces of freshly exposed rocks? |
| A. | green algae |
| B. | diatoms |
| C. | cyanobacteria |
| D. | yeast |
| Answer» D. yeast | |
| 57. |
The crops which are involved in nitrogen fixation are |
| A. | alfalfa and clover |
| B. | soybean |
| C. | bean and lupine |
| D. | all of these |
| Answer» E. | |
| 58. |
Nitrogen fixation by the microorganisms can be detected by adopting the approach of |
| A. | demonstrating growth in a nitrogen free medium |
| B. | cultivating the microorganisms in the presence of nitrogen labeled with isotropic nitrogen |
| C. | measuring15N2 by mass spectrometer |
| D. | all of the above |
| Answer» E. | |
| 59. |
The amount of organic material in the forest soil remains approximately the same from year to year. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 60. |
Cellulose is degraded to cellobiose by the enzyme __________________ |
| A. | cellulase |
| B. | beta-glucosidase |
| C. | hexokinase |
| D. | cellulose dehydrogenase |
| Answer» B. beta-glucosidase | |
| 61. |
Fresh air contains approximately ______ percent carbon dioxide by volume. |
| A. | 0.01 |
| B. | 2 |
| C. | 5 |
| D. | 0.03 |
| Answer» E. | |
| 62. |
In carbon cycle flow of energy is _________________ |
| A. | bidirectional |
| B. | linear |
| C. | cyclic |
| D. | irreversible |
| Answer» C. cyclic | |
| 63. |
Bacteria are likely to be more prevalent in soils of vineyards, orchards and apiaries. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 64. |
Parasitism results from competition among organisms for essential nutrients. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 65. |
Hydrostatic pressure increases the boiling point of water but does not change the solubility of nutrients. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 66. |
Alanine gives pyruvic acid on deamination. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 67. |
How much time does nitrifying bacteria requires to grow at an incubation of 250 to 300 C? |
| A. | 1 day |
| B. | 2-3 days |
| C. | 15 days |
| D. | 1 to 4 months |
| Answer» E. | |
| 68. |
Nitrosococcus nitrosus is a nitrite-oxidizing bacteria. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 69. |
Thermus aquaticus, a common bacterial inhabitant generally prevails in temperatures of ____________ |
| A. | 0° C |
| B. | 30-40°C |
| C. | 70-72°C |
| D. | 80-85°C |
| Answer» D. 80-85°C | |
| 70. |
Primary producers are found growing in which of the following layers of water? |
| A. | upper layer |
| B. | middle layer |
| C. | intermediate layer |
| D. | bottom layer |
| Answer» B. middle layer | |
| 71. |
Which of the following is subterranean water? |
| A. | Atmospheric water |
| B. | Surface water |
| C. | Groundwater |
| D. | Rainwater |
| Answer» D. Rainwater | |
| 72. |
Denitrification is carried out |
| A. | usually by facultative anaerobes |
| B. | predominantly by Pseudomonas spp |
| C. | predominantly by Bacillus spp |
| D. | all of the above |
| Answer» E. | |
| 73. |
An example of a symbiotic nitrogen fixer is |
| A. | Azotobacter |
| B. | Beijerinckia |
| C. | Clostridium |
| D. | Rhizobium |
| Answer» E. | |
| 74. |
The dominant mineral particles in most soils are compounds of _____________ |
| A. | sodium |
| B. | potassium |
| C. | magnesium |
| D. | iron |
| Answer» E. | |
| 75. |
Denitrification may be distinguished as |
| A. | dissimilative |
| B. | assimilative |
| C. | both (a) and (b) |
| D. | blue baby syndrome |
| Answer» D. blue baby syndrome | |
| 76. |
Which of the following comes under the category of positive association? |
| A. | neutralism |
| B. | parasitism |
| C. | commensalism |
| D. | ammensalism |
| Answer» D. ammensalism | |
| 77. |
The red or pink color of the fish is generally caused from the growth of |
| A. | Sarcina |
| B. | Micrococcus or Bacillus species |
| C. | Molds or yeasts |
| D. | all of these |
| Answer» E. | |
| 78. |
The bacteria most often involved in the spoilage of fish are |
| A. | part of the natural flora of the external slime of fishes and their intestinal contents |
| B. | part of the natural flora of the internal slime of fishes only |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» B. part of the natural flora of the internal slime of fishes only | |
| 79. |
The amount of oxygen dissolved in hypolimnion water in the winter is __________ to/than the amount of oxygen dissolved in hypolimnion water in the summer |
| A. | greater |
| B. | lesser |
| C. | approximately equal to |
| D. | half |
| Answer» B. lesser | |
| 80. |
Agrobacterium is involved in which of the following processes? |
| A. | Ammonification |
| B. | Nitrification |
| C. | Reduction of nitrate to ammonia |
| D. | Denitrification |
| Answer» E. | |
| 81. |
The population of algae in soil is __________ that of either bacteria or fungi. |
| A. | generally smaller than |
| B. | generally greater than |
| C. | equal to |
| D. | none of these |
| Answer» B. generally greater than | |
| 82. |
The groups of bacteria which have the ability to fix nitrogen from air to soil are |
| A. | symbiotic |
| B. | nonsymbiotic |
| C. | both (a) and (b) |
| D. | none of these |
| Answer» D. none of these | |
| 83. |
Which among the following factors are limiting growth of phytoplankton organisms? |
| A. | carbon dioxide |
| B. | radiant energy |
| C. | water |
| D. | radiant energy,nitrogen |
| Answer» E. | |
| 84. |
Which of the following zones have considerable rooted vegetation? |
| A. | littoral zone |
| B. | limnetic zone |
| C. | profundal zone |
| D. | benthic zone |
| Answer» B. limnetic zone | |
| 85. |
Which of the following species of different genera of bacteria are not capable of transforming nitrate to nitrogen? |
| A. | Achromobacter |
| B. | Agrobacterium |
| C. | Alcaligenes |
| D. | None of these |
| Answer» E. | |
| 86. |
Which of the following is capable of oxidizing sulfur to sulfates? |
| A. | Thiobacillus thiooxidans |
| B. | Desulfotomaculum |
| C. | Rhodospirillum |
| D. | Rhodomicrobium |
| Answer» B. Desulfotomaculum | |
| 87. |
The groups of symbiotic bacteria, which have the ability to fix nitrogen |
| A. | derive their food and minerals from the legume, and in turn they supply the legume with some or all of its nitrogen |
| B. | grow together for a mutual benefit is called symbiosis and so these bacteria are called symbiotic nitrogen-fixing bacteria |
| C. | these bacteria are from the genus, Rhizobium |
| D. | all of the above |
| Answer» E. | |
| 88. |
In the process of nitrogen fixation, which of the following microorganism is involved? |
| A. | Non symbiotic microorganisms only |
| B. | Symbiotic microorganisms only |
| C. | Non symbiotic and symbiotic microorganisms only |
| D. | None of the above |
| Answer» D. None of the above | |
| 89. |
Protozoa and other minute animal life are known as ____________________ |
| A. | plankton |
| B. | phytoplankton |
| C. | zooplankton |
| D. | mycoplankton |
| Answer» D. mycoplankton | |
| 90. |
The diagnostic enzyme for nitrogen-fixing organisms is |
| A. | nitrogenase |
| B. | nitrate reductase |
| C. | nitrate oxidase |
| D. | none of these |
| Answer» B. nitrate reductase | |
| 91. |
The biological activity of an aquatic ecosystem is dependent upon which of the following factors? |
| A. | number of primary producers |
| B. | amount of chemical energy produced |
| C. | rate of primary production |
| D. | number of deaths of organisms |
| Answer» D. number of deaths of organisms | |
| 92. |
Which are the main source of biofertilisers? |
| A. | Cyanobacteria |
| B. | Bacillus |
| C. | Streptococcus |
| D. | None of these |
| Answer» B. Bacillus | |
| 93. |
Degree of compost maturity can be assesed by |
| A. | infrared technique |
| B. | germination test |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 94. |
The transformation of nitrates to gaseous nitrogen is accomplished by microorganisms in a series of biochemical reactions. The process is known as |
| A. | nitrification |
| B. | denitrification |
| C. | nitrogen fixation |
| D. | ammonification |
| Answer» C. nitrogen fixation | |
| 95. |
The term fertility of oceans is used to express the capacity for production of inorganic matter. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 96. |
The Winogradsky column experiment is done in the dark. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 97. |
Sulphates are reduced to hydrogen sulphide by _____________________ |
| A. | Desulfotomaculum sp. |
| B. | Thiobacillus thiooxidans |
| C. | Photosynthetic sulfur bacteria |
| D. | Rhodospirillum |
| Answer» B. Thiobacillus thiooxidans | |
| 98. |
The reduction of sulphates and sulphites to hydrogen sulphide is done by which group of bacteria? |
| A. | aerobic sulfate-reducing bacteria |
| B. | photosynthetic sulphur bacteria |
| C. | anaerobic sulphate-reducing bacteria |
| D. | heterotrophic bacteria |
| Answer» D. heterotrophic bacteria | |
| 99. |
The moisture contained in clouds and precipitated as snow,hail,rain etc constitutes _________________ |
| A. | Atmospheric water |
| B. | Surface water |
| C. | Groundwater |
| D. | Subterranean water |
| Answer» B. Surface water | |
| 100. |
Which among the following is a non-sulfur purple bacteria? |
| A. | Rhodomicrobium |
| B. | Thiobacillus |
| C. | Chromatium |
| D. | Chlorobium |
| Answer» B. Thiobacillus | |