 
			 
			MCQOPTIONS
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				This section includes 71 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology knowledge and support exam preparation. Choose a topic below to get started.
| 1. | For each glucose molecule broken down, there are______________number of reduced coenzymes to be oxidized. | 
| A. | 12 | 
| B. | 8 | 
| C. | 6 | 
| D. | 4 | 
| Answer» B. 8 | |
| 2. | The phosphate inhibition in the clavine formation with SD58, can be counteracted by the addition of | 
| A. | alanine | 
| B. | methionine | 
| C. | tryptophan | 
| D. | lysine | 
| Answer» D. lysine | |
| 3. | The major route for incorporation of ammonia (NH) into organic compounds is via | 
| A. | reduction of pyruvate or alpha-ketoglutarate by enzymes | 
| B. | atmospheric nitrogen fixation | 
| C. | oxidation of pyruvate | 
| D. | all of these | 
| Answer» B. atmospheric nitrogen fixation | |
| 4. | Incorporation of atmospheric Nto NH occurs via the process of | 
| A. | assimilatory nitrate reduction | 
| B. | transamination | 
| C. | deamination | 
| D. | nitrogen fixation | 
| Answer» E. | |
| 5. | Standard free energy change (ΔG) can be expressed as | 
| A. | ΔG° = -RTlnk | 
| B. | ΔG° = RTlnk | 
| C. | ΔG° = R/Tlnk | 
| D. | ΔG° = -RT/lnk | 
| Answer» B. ΔG° = RTlnk | |
| 6. | Aerobic catabolism of glucose yields how much energy (ATP synthesized) relative to glucose fermentation? | 
| A. | Slightly less | 
| B. | About the same | 
| C. | Twice as much | 
| D. | More than 10 times as much | 
| Answer» E. | |
| 7. | The bacteriochlorophylls used by the anoxygenic bacteria have absorbance maxima located in the_____portion(s) of the spectrum. | 
| A. | green | 
| B. | blue | 
| C. | ultraviolet | 
| D. | infrared | 
| Answer» E. | |
| 8. | The relationship between an oxidation-reduction potential difference and the standard free energy change is (where n is the number of moles of electron transferred, F= Faraday's constant and E°= standard oxidation-reduction potential difference) | 
| A. | ΔG° = -nFE° | 
| B. | ΔG° = nFE° | 
| C. | ΔG° = -nFlnE° | 
| D. | ΔG° = nFlnE° | 
| Answer» B. ΔG° = nFE° | |
| 9. | ATPase | 
| A. | synthesizes ATP, coupled to transfer of extracellular protons into the cell | 
| B. | extrudes protons from the cell coupled to the hydrolysis of ATP to ADP | 
| C. | is the enzyme that incorporates ATP into messenger RNA | 
| D. | carries out each of the reactions indicated in (a) and (b) | 
| Answer» E. | |
| 10. | Entner - Doudoroff pathway is not found in | 
| A. | aerobic prokaryotes | 
| B. | anaerobic prokaryotes | 
| C. | Both (a) and (b) | 
| D. | eukaryotes | 
| Answer» E. | |
| 11. | Phosphate deregulated mutants are | 
| A. | less sensitive to phosphate regulation | 
| B. | moderately sensitive to phosphate regulation | 
| C. | highly sensitive to phosphate regulation | 
| D. | none of these | 
| Answer» B. moderately sensitive to phosphate regulation | |
| 12. | The mechanism of passive or facilitated diffusion require | 
| A. | metabolic energy | 
| B. | concentration of solute against an electrochemical gradient | 
| C. | accumulation of solute against an electrochemical gradient | 
| D. | accumulation or concentration of solute against an electrochemical gradient | 
| Answer» B. concentration of solute against an electrochemical gradient | |
| 13. | Nitrogen fixation is a process that requires | 
| A. | energy | 
| B. | an anaerobic environment | 
| C. | both (a) and (b) | 
| D. | an aerobic environment | 
| Answer» D. an aerobic environment | |
| 14. | Bacteriochlorophyll differs from chlorophyll in what way? | 
| A. | The chelated metal in bacteriochlorophyll is not Mg | 
| B. | There are chemical differences between the two chlorophyll in their side (R) groups | 
| C. | They have different absorption spectra | 
| D. | Both (b) and (c) | 
| Answer» E. | |
| 15. | If ΔG of a chemical reaction is positive in value and k is less than 1 then the chemical reaction will | 
| A. | proceed in reverse direction | 
| B. | proceeed in forward direction | 
| C. | not take place in any of the direction | 
| D. | none of these | 
| Answer» B. proceeed in forward direction | |
| 16. | Radioisotopes are frequently used in the study of cells. Assume a culture of is grown in a culture medium containing radioactive sulphur. At the end of 48 hours, it is expected to find the radioactive label located in | 
| A. | DNA | 
| B. | enzymes | 
| C. | RNA | 
| D. | all of these | 
| Answer» C. RNA | |
| 17. | Assimilatory sulfate reduction involves the nucleotide __________ during the incorporation of HS in the production of __________ . | 
| A. | ATP; methionine | 
| B. | ATP; cytosine | 
| C. | UTP; cytosine | 
| D. | GTP; cytosine | 
| Answer» C. UTP; cytosine | |
| 18. | During the carboxylation phase of the Calvin cycle, CO combines with | 
| A. | ribulose 1,5 - bisphosphate | 
| B. | phosphoglyceraldehyde | 
| C. | pyruvic acid | 
| D. | oxaloacetic acid | 
| Answer» B. phosphoglyceraldehyde | |
| 19. | Which of the following groups contain(s) many unique coenzymes, such as coenzyme M and coenzyme F? | 
| A. | Sulfate-reducing bacteria | 
| B. | Methanotrophs (methane-oxidizing microbes) | 
| C. | Methanogens (methane-producing microbes) | 
| D. | Acetogens (acetigens; acetate-producing microbes) | 
| Answer» D. Acetogens (acetigens; acetate-producing microbes) | |
| 20. | Radioisotopes are frequently used in the study of cells. Assume a culture of is grown in a culture medium containing radioactive phosphorous. At the end of 48 hours, it is expected to find the radioactive label located in | 
| A. | enzymes | 
| B. | RNA | 
| C. | phospholipids | 
| D. | all of these | 
| Answer» E. | |
| 21. | High energy transfer compounds are capable of | 
| A. | accepting large amounts of free energy | 
| B. | transferring large amounts of free energy | 
| C. | measuring free energy | 
| D. | none of the above | 
| Answer» C. measuring free energy | |
| 22. | If G of a chemical reaction is positive in value and keq is less than 1 then the chemical reaction will | 
| A. | proceed in reverse direction | 
| B. | proceeed in forward direction | 
| C. | not take place in any of the direction | 
| D. | none of these | 
| Answer» B. proceeed in forward direction | |
| 23. | Assimilatory sulfate reduction involves the nucleotide __________ during the incorporation of H2S in the production of __________ . | 
| A. | ATP; methionine | 
| B. | ATP; cytosine | 
| C. | UTP; cytosine | 
| D. | GTP; cytosine | 
| Answer» C. UTP; cytosine | |
| 24. | The chlorophyll molecules used by eucaryotes and cyanobacteria absorb radiant energy in the____________portion(s) of the visible spectrum. | 
| A. | red | 
| B. | green | 
| C. | red and blue | 
| D. | green and ultraviolet | 
| Answer» D. green and ultraviolet | |
| 25. | In aerobic respiration, the terminal electron acceptor is | 
| A. | oxygen | 
| B. | nitrogen | 
| C. | hydrogen | 
| D. | nitrate | 
| Answer» B. nitrogen | |
| 26. | The reactions of the cell that are carried out for capturing energy are called | 
| A. | catabolism | 
| B. | metabolism | 
| C. | anabolism | 
| D. | activation energy | 
| Answer» B. metabolism | |
| 27. | In establishing proton gradient for chemiosmotic ATP generation by aerobic respiration the terminal electron acceptor is | 
| A. | nitrate | 
| B. | oxygen | 
| C. | sulfate | 
| D. | CO | 
| E. | <sub>2</sub> | 
| Answer» C. sulfate | |
| 28. | During the carboxylation phase of the Calvin cycle, CO2 combines with | 
| A. | ribulose 1,5 - bisphosphate | 
| B. | phosphoglyceraldehyde | 
| C. | pyruvic acid | 
| D. | oxaloacetic acid | 
| Answer» B. phosphoglyceraldehyde | |
| 29. | Which of the following groups contain(s) many unique coenzymes, such as coenzyme M and coenzyme F420? | 
| A. | Sulfate-reducing bacteria | 
| B. | Methanotrophs (methane-oxidizing microbes) | 
| C. | Methanogens (methane-producing microbes) | 
| D. | Acetogens (acetigens; acetate-producing microbes) | 
| Answer» D. Acetogens (acetigens; acetate-producing microbes) | |
| 30. | Radioisotopes are frequently used in the study of cells. Assume a culture of E. coli is grown in a culture medium containing radioactive phosphorous. At the end of 48 hours, it is expected to find the radioactive label located in | 
| A. | enzymes | 
| B. | RNA | 
| C. | phospholipids | 
| D. | all of these | 
| Answer» E. | |
| 31. | Which of the following is responsible for phosphate solubilization? | 
| A. | <i>Streptococcus </i> | 
| B. | <i>Streptomyces</i> | 
| C. | <i>Bacillus</i> | 
| D. | <i>Clostridium</i> | 
| Answer» D. <i>Clostridium</i> | |
| 32. | Phosphate deregulated mutants are | 
| A. | less sensitive to phosphate regulation | 
| B. | moderately sensitive to phosphate regulation | 
| C. | highly sensitive to phosphate regulation | 
| D. | none of these | 
| Answer» B. moderately sensitive to phosphate regulation | |
| 33. | The mechanism of passive or facilitated diffusion require | 
| A. | metabolic energy | 
| B. | concentration of solute against an electrochemical gradient | 
| C. | accumulation of solute against an electrochemical gradient | 
| D. | accumulation or concentration of solute against an electrochemical gradient | 
| Answer» B. concentration of solute against an electrochemical gradient | |
| 34. | Nitrogen fixation is a process that requires | 
| A. | energy | 
| B. | an anaerobic environment | 
| C. | both (a) and (b) | 
| D. | an aerobic environment | 
| Answer» D. an aerobic environment | |
| 35. | The phosphate inhibition in the clavine formation with Claviceps SD58, can be counteracted by the addition of | 
| A. | alanine | 
| B. | methionine | 
| C. | tryptophan | 
| D. | lysine | 
| Answer» D. lysine | |
| 36. | The major route for incorporation of ammonia (NH4+) into organic compounds is via | 
| A. | reduction of pyruvate or alpha-ketoglutarate by enzymes | 
| B. | atmospheric nitrogen fixation | 
| C. | oxidation of pyruvate | 
| D. | all of these | 
| Answer» B. atmospheric nitrogen fixation | |
| 37. | The specific enzyme/(s) of the glyoxylate cycle is/are | 
| A. | isocitrate lyase | 
| B. | malate synthase | 
| C. | both (a) and (b) | 
| D. | anaplerotic | 
| Answer» D. anaplerotic | |
| 38. | Digestive reactions where large molecules are broken down into smaller ones are referred as | 
| A. | anabolism | 
| B. | catabolism | 
| C. | metabolism | 
| D. | biosynthesis | 
| Answer» C. metabolism | |
| 39. | Most of the energy in aerobic respiration of glucose is captured by | 
| A. | substrate-level phosphorylation | 
| B. | electron transport of electrons from NADH | 
| C. | long-chain fatty acid oxidation | 
| D. | the enzyme formic-hydrogen lyase | 
| Answer» C. long-chain fatty acid oxidation | |
| 40. | In order to get inorganic phosphorous into organic compounds, the phosphate ion is incorporated via | 
| A. | substrate level phosphorylation | 
| B. | oxidative phosphorylation | 
| C. | both (a) and (b) | 
| D. | DNA | 
| Answer» D. DNA | |
| 41. | Anoxygenic photosynthetic bacteria oxidize | 
| A. | water | 
| B. | oxgyen | 
| C. | sulfide | 
| D. | ammonia | 
| Answer» D. ammonia | |
| 42. | Which of the following catalyze liberation of orthophosphate from organic P compounds and inorganic pyrophosphate ? | 
| A. | Alkaline phosphates | 
| B. | Oxidoreductase | 
| C. | Protease | 
| D. | Hydrogenase | 
| Answer» B. Oxidoreductase | |
| 43. | For each glucose molecule broken down, there are______________number of reduced coenzymes to be oxidized. | 
| A. | 12 | 
| B. | 8 | 
| C. | 6 | 
| D. | 4 | 
| Answer» B. 8 | |
| 44. | As the electron flow through the chains, much of their free energy is conserved in the form of ATP. This process is called | 
| A. | oxidative phosphorylation | 
| B. | electromotive potential | 
| C. | dehydrogenations | 
| D. | none of these | 
| Answer» B. electromotive potential | |
| 45. | The glyoxylate cycle is used by some microorganisms when___________ is the sole carbon source. | 
| A. | acetate | 
| B. | nitrate | 
| C. | carbon dioxide | 
| D. | all of these | 
| Answer» B. nitrate | |
| 46. | The role of bacteriophyll in an oxygenic photosynthesis is to | 
| A. | reduce ferridoxin directly | 
| B. | reduce NADP directly | 
| C. | use light energy to energize an electron | 
| D. | transfer electrons to an intermediate in the sulfide oxidation pathway | 
| Answer» D. transfer electrons to an intermediate in the sulfide oxidation pathway | |
| 47. | The reaction, where small precursor molecules are assembled into larger organic molecules is referred as | 
| A. | anabolism | 
| B. | catabolism | 
| C. | metabolism | 
| D. | any of these | 
| Answer» B. catabolism | |
| 48. | DAHP synthetase catalyzes the condensation of | 
| A. | erythrose-4-phosphate | 
| B. | phosphoenol pyruvate | 
| C. | both (a) and (b) | 
| D. | phenylalanine | 
| Answer» D. phenylalanine | |
| 49. | Hexose monophosphate pathway is also known as | 
| A. | phosphogluconate pathway | 
| B. | oxaloacetate pathway | 
| C. | malate pathway | 
| D. | fumerate pathway | 
| Answer» B. oxaloacetate pathway | |
| 50. | Bacteriochlorophyll differs from chlorophyll in what way? | 
| A. | The chelated metal in bacteriochlorophyll is not Mg | 
| B. | There are chemical differences between the two chlorophyll in their side (R) groups | 
| C. | They have different absorption spectra | 
| D. | Both (b) and (c) | 
| Answer» E. | |