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.
| 101. |
Which among the following develop in the upper portion of the Winogradsky column? |
| A. | Sulfate-reducing bacteria |
| B. | Green-sulfur bacteria |
| C. | Purple-sulfur bacteria |
| D. | Thiobacilli |
| Answer» E. | |
| 102. |
The surface waters are susceptible to contamination with microorganisms from _______________ |
| A. | the air |
| B. | the surface runoff |
| C. | precipitation |
| D. | atmospheric water and the surface runoff |
| Answer» E. | |
| 103. |
Metabolism of dissolved organic material released by phytoplankton allows heterotrophic bacteria to become part of the particulate organic matter that is passed up the food web to be metabolized and released as mineral elements and CO2 at each transfer. This sentence describes the |
| A. | microbial loop |
| B. | Winogradsky column |
| C. | Redfield ratio |
| D. | Gibbs free energy |
| Answer» B. Winogradsky column | |
| 104. |
Which of the following are not the features of component II of nitrogenase enzyme complex? |
| A. | component II is nitrogenase reductase |
| B. | component II is known as the MoFe protein |
| C. | contains sulfur |
| D. | not active without component I |
| Answer» C. contains sulfur | |
| 105. |
Which of the following is not the biofertilisers producing bacteria? |
| A. | Nostoc |
| B. | Anabaena |
| C. | Both (a) and (b) |
| D. | Clostridium |
| Answer» E. | |
| 106. |
The conversion of molecular nitrogen into ammonia is known as |
| A. | nitrification |
| B. | denitrification |
| C. | nitrogen fixation |
| D. | ammonification |
| Answer» D. ammonification | |
| 107. |
Which of the following statement is not true about composition of biogas? |
| A. | It is composed almost exclusively of methane and carbon dioxide |
| B. | It also contains with traces of H2S, N2, H2and CO |
| C. | It also contains with traces of O2 and Cl2 |
| D. | Both (a) and (b) |
| Answer» D. Both (a) and (b) | |
| 108. |
The predominant kind of bacteria causing spoilage in fish at chilling temperature is |
| A. | species of Pseudomonas |
| B. | Micrococcus |
| C. | Bacillus |
| D. | none of these |
| Answer» B. Micrococcus | |
| 109. |
Ammonia oxidizers and nitrite oxidizers are ________________________ |
| A. | Gram-negative chemolithotrophs |
| B. | Gram-positive chemolithotrophs |
| C. | Gram-negative photolithotrophs |
| D. | Gram-positive photolithotrophs |
| Answer» B. Gram-positive chemolithotrophs | |
| 110. |
Rapidly expanding urbanization makes it difficult to generalize upon typical microbial flora of streams. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 111. |
Purple and green sulfur bacteria use ___________________ as the electron donor to reduce carbon dioxide. |
| A. | S2- |
| B. | SO42- |
| C. | H2S |
| D. | Organic acids |
| Answer» D. Organic acids | |
| 112. |
Members of all of the following genera of bacteria typically are found in a maturing Winogradsky column except |
| A. | Clostridium |
| B. | Rhodospirillum |
| C. | Chlorobium |
| D. | Escherichia |
| Answer» E. | |
| 113. |
Nitrogen fixation refers to the direct conversion of atmospheric nitrogen gas into |
| A. | ammonia |
| B. | glucose |
| C. | ATP |
| D. | nitrate |
| Answer» B. glucose | |
| 114. |
Cysteine breaks down in presence of cysteine desulfurase to give _________________ |
| A. | oxaloacetic acid |
| B. | sulphuric acid |
| C. | pyruvic acid |
| D. | glyoxalate |
| Answer» D. glyoxalate | |
| 115. |
Which of the following species in water reveal the presence of fecal pollution of human or animal origin? |
| A. | E.coli |
| B. | Fecal Streptococci |
| C. | Clostridium perfringens |
| D. | All of these |
| Answer» E. | |
| 116. |
Wells less than ___________ deep are considered to be shallow. |
| A. | 1 ft |
| B. | 100 ft |
| C. | 50 ft |
| D. | 1000 ft |
| Answer» C. 50 ft | |
| 117. |
Which of the following places shows presence of Geothermal vents? |
| A. | Coasts of California |
| B. | Coasts of Peru |
| C. | Galapagos islands |
| D. | Pacific ocean |
| Answer» D. Pacific ocean | |
| 118. |
In regions of the estuary that are nutritionally poor, it is more likely to find which of the following organisms? |
| A. | coliforms |
| B. | appendaged bacteria |
| C. | viruses |
| D. | fecal streptococci |
| Answer» C. viruses | |
| 119. |
Normally, due to the holding of the chilled fish |
| A. | Pseudomonas increase in numbers |
| B. | Achromobacters decrease |
| C. | Flavobacteria increase temporarily and then decrease |
| D. | all of the above |
| Answer» E. | |
| 120. |
The primary producers transform radiant energy into heat energy. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 121. |
A musty or muddy odor of the fish is attributed to |
| A. | the growth of Streptomyces species in the mud at the bottom of the body of water |
| B. | the mud at the bottom of the body of water |
| C. | the growth of Pseudomonas species in the mud at the bottom of the body of water |
| D. | none of the above |
| Answer» B. the mud at the bottom of the body of water | |
| 122. |
Which of the following genus of bacteria is not found in fresh waters? |
| A. | Pseudomonas |
| B. | Flavobacterium |
| C. | Aeromonas |
| D. | Vibrio |
| Answer» E. | |
| 123. |
The breakdown of cattle manure in biogas is accomplished by which of the following type of bacteria? |
| A. | Hydrolytic |
| B. | Transitional |
| C. | methanogenic |
| D. | All of these |
| Answer» E. | |
| 124. |
Most soil protozoa are flagellates or amoebas, having their dominant mode of nitrogen as |
| A. | ingestion of bacteria |
| B. | ingestion of mold |
| C. | ingestion of fungi |
| D. | all of these |
| Answer» B. ingestion of mold | |
| 125. |
The microbial ecosystem of soil includes |
| A. | biotic components of soil |
| B. | abiotic components of soil |
| C. | biotic and abiotic components of soil |
| D. | none of the above |
| Answer» D. none of the above | |
| 126. |
Which of the following microorganism use H2S as the electron donor to reduce carbon dioxide? |
| A. | Chromaticum |
| B. | Chlorobium |
| C. | Both (a) and (b) |
| D. | Rhodomicrobium |
| Answer» D. Rhodomicrobium | |
| 127. |
Which among the following are referred to as the “pasture of the sea”? |
| A. | fishes |
| B. | algae |
| C. | nematodes |
| D. | phytoplankton |
| Answer» E. | |
| 128. |
Nitrogen fixation |
| A. | changes the free nitrogen (N2) to a form usable by plants |
| B. | especially changes nitrogen compounds, mostly amines such as NH2 |
| C. | both (a) and (b) |
| D. | fix the free nitrogen (N2) by which it should not be usable by plants |
| Answer» D. fix the free nitrogen (N2) by which it should not be usable by plants | |
| 129. |
Microbial inhabitants of the bottom region of a body of water are referred to as ________________ |
| A. | phytoplankton |
| B. | benthic organisms |
| C. | zooplankton |
| D. | mycoplankton |
| Answer» C. zooplankton | |
| 130. |
Trickling filter comes under |
| A. | primary treatment |
| B. | secondary treatment |
| C. | tertiary treatment |
| D. | none of these |
| Answer» C. tertiary treatment | |
| 131. |
For rapid decomposition by microbes, the substrate should have a C/N ratio of |
| A. | 10-20 |
| B. | 20-30 |
| C. | 30-40 |
| D. | 60-80 |
| Answer» D. 60-80 | |
| 132. |
Which of the following processes is performed by Thiobacillus thiooxidans? |
| A. | converting sulphur to sulphates |
| B. | converting sulphur to sulphides |
| C. | converting sulphur to sulphites |
| D. | converting organic sulphur to inorganic sulphur |
| Answer» B. converting sulphur to sulphides | |
| 133. |
Denitrification is |
| A. | reduction of nitrate (NO3-) to nitrogen gas |
| B. | reduction of nitrate to organic nitrogen compounds |
| C. | both (a) and (b) |
| D. | changing of atmospheric nitrogen (N2) to nitrogen compounds |
| Answer» D. changing of atmospheric nitrogen (N2) to nitrogen compounds | |
| 134. |
Which among the following is not an ammonia-oxidizing bacteria? |
| A. | Nitrosomonas europaea |
| B. | Nitrosovibrio tenuis |
| C. | Nitrospina gracilis |
| D. | Nitrosococcus oceanus |
| Answer» D. Nitrosococcus oceanus | |
| 135. |
The characteristic color of the Red Sea is associated with heavy blooms of __________________ |
| A. | diatoms |
| B. | cyanobacteria |
| C. | dinoflagellates |
| D. | chlamydomonads |
| Answer» C. dinoflagellates | |
| 136. |
Cellobiose is metabolized directly by many microorganisms. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 137. |
__________ play a key role in the transformation of rock to soil. |
| A. | Cyanobacteia |
| B. | Pectin decomposing bacteria |
| C. | Nitrifying bacteria |
| D. | De-nitrifying bacteria |
| Answer» B. Pectin decomposing bacteria | |
| 138. |
Assimilative denitrification is done by |
| A. | plants |
| B. | fungi |
| C. | prokaryotes |
| D. | all of these |
| Answer» E. | |
| 139. |
The association which involves the exchange of nutrients between two species is referred to as ______________ |
| A. | mutualism |
| B. | syntrophism |
| C. | commensalism |
| D. | antagonism |
| Answer» C. commensalism | |
| 140. |
Fungi produces which of the following inhibitory toxic product? |
| A. | cyanide |
| B. | fatty acids |
| C. | methane |
| D. | sulphides |
| Answer» B. fatty acids | |
| 141. |
Lytic enzymes which destroy are secreted by which of the following microorganism? |
| A. | fungi |
| B. | algae |
| C. | staphylococcus |
| D. | myxobacteria |
| Answer» E. | |
| 142. |
Which of the following types of association is present among Staphylococcus aureus and Aspergillus terreous? |
| A. | antagonism |
| B. | mutualism |
| C. | parasitism |
| D. | commensalism |
| Answer» B. mutualism | |
| 143. |
The degradation of complex molecules in soil by fungi for utilization by bacteria is an example of which type of association? |
| A. | Neutralism |
| B. | Mutualism |
| C. | Commensalism |
| D. | Antagonism |
| Answer» D. Antagonism | |