56 TOP MICROBIAL METABOLISM Questions and Answers

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1. 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: A

2. 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: C

3. In the passive diffusion, solute molecules cross the membrane as a result of

A. concentration difference
B. pressure difference
C. ionic difference
D. all of these

Answer: A

4. In an oxygenic photosynthesis, the green and the purple bacteria do not use which of the following one as an electron source?

A. H2O
B. H2
C. H2S
D. S (elemental sulphur)

Answer: A

5. 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: D

6. 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: B

8. In aerobic respiration, the terminal electron acceptor is

A. oxygen B. nitrogen
C. hydrogen D. nitrate

Answer: A

9. Which of the following statement is correct?

A. Phosphate repression can not be eliminated by optimization of nutrient medium, deregulated medium must be used as production strains
B. Phosphate repression can be eliminated by optimization of nutrient medium, deregulated medium must be used as production strains
C. Phosphate repression can be eliminated by optimization of nutrient medium, regulated medium must be used as production strains
D. Phosphate repression can not be eliminated by optimization of nutrient medium, regulated medium must be used as production strains

Answer: A

10. The acquisition energy by glucose fermentation requires

A. substrate-level phosphorylation
B. electron transport of electrons from NADH
C. long-chain fatty acid oxidation
D. the enzyme formic-hydrogen lyase

Answer: A

11. 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: B

13. The reactions of the cell that are carried out for capturing energy are called

A. catabolism
B. metabolism
C. anabolism
D. activation energy

Answer: A

14. In establishing proton gradient for chemiosmotic ATP generation by aerobic respiration the terminal electron acceptor is

A. nitrate
B. oxygen
C. sulfate
D. CO2

Answer: B

15. If ΔG 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: A

16. 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: A

17. Which of the following nucleoside diphosphates is used most often in carbohydrate anabolism?

A. Uridine diphosphate
B. Adenosine diphosphate
C. Guanine diphosphate
D. Thymine diphosphate

Answer: A

18. DAHP synthetase catalyzes the condensation of

A. erythrose-4-phosphate
B. phosphoenol pyruvate
C. both (a) and (b)
D. phenylalanine

Answer: C

19. Phosphate is considered to restrict the induction of

A. primary metabolites
B. secondary metabolites
C. both (a) and (b)
D. none of these

Answer: B

20. Free energy change (ΔG) of a reaction is referred as the amount of energy

A. liberated during reaction
B. taken up during reaction
C. liberated or taken up during reaction
D. none of these

Answer: C

21. Which of the following does not produce oxygen as a product of photosynthesis?

A. Oak trees
B. Purple sulfur bacteria
C. Cyanobacteria
D. Phytoplankton

Answer: B

22. When acetate is the sole source of carbon for some microorganisms, the cycle which is used, is called

A. pentose phosphate pathway
B. glycolyic pathway
C. glyoxylate pathway
D. oxaloacetate pathway

Answer: C

23. Hexose monophosphate pathway is also known as

A. phosphogluconate pathway
B. oxaloacetate pathway
C. malate pathway
D. fumerate pathway

Answer: A

24. If radioactive bicarbonate was supplied to bacterial cells, which were actively synthesizing fatty acids, it is expected to find the bulk of the radioactivity in

A. cellular bicarbonate
B. the fatty acids
C. the cytoplasmic membrane
D. nucleic acids

Answer: A

25. Standard free energy change (ΔG) can be expressed as

A. ΔG° = -RTlnkeq
B. ΔG° = RTlnkeq
C. ΔG° = R/Tlnkeq
D. ΔG° = -RT/lnkeq

Answer: A

26. 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: A

27. Incorporation of atmospheric N2to NH4+ occurs via the process of

A. assimilatory nitrate reduction
B. transamination
C. deamination
D. nitrogen fixation

Answer: D

28. 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: C

29. TCA cycle functions in

A. catabolic reactions
B. anabolic reactions
C. amphibolic reactions
D. none of these

Answer: C

30. Entner-Doudoroff pathway is found in

A. aerobic prokaryotes
B. anaerobic prokaryotes
C. both (a) and (b)
D. aerobic eukaryotes

Answer: C

MICROBIAL METABOLISM Questions and Answers pdf ::

31. Anoxygenic photosynthetic bacteria oxidize

A. water B. oxgyen
C. sulfide D. ammonia

Answer: C

32. Which of the following(s) is/are the products of the light reactions of photosynthesis?

A. ATP only
B. NADPH only
C. ATP and O2 only
D. ATP, NADPH, and O2

Answer: D

33. 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: A

34. For each glucose molecule broken down, there are______________number of reduced coenzymes to be oxidized.

A. 12
B. 8
C. 6
D. 4

Answer: A

35. 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: A

36. Digestive reactions where large molecules are broken down into smaller ones are referred as

A. anabolism B. catabolism
C. metabolism D. biosynthesis

Answer: B

37. Phosphate regulation has been observed in the production of

A. alkaloids
B. antibiotics
C. gibberelins
D. all of these

Answer: D

38. 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: B

39. During the reduction phase of the Calvin cycle, phosphoglyceric acid is reduced to______utilizing________as the reduction source.

A. phosphoglyceraldehyde; NADPH+H+
B. phosphoglyceraldehyde; NADH+H+
C. ribulose 1,5 – bisphosphate; NADH+H+
D. pyruvic acid; NADPH+H+

Answer: A

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: C

41. 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: C

42. 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: A

43. The specific enzyme/(s) of the glyoxylate cycle is/are

A. isocitrate lyase
B. malate synthase
C. both (a) and (b)
D. anaplerotic

Answer: C

44. If ΔG of a chemical reaction has a negative value, the reaction

A. releases energy
B. requires energy
C. both (a) and (b)
D. none of these

Answer: A

45. The catabolic reaction, pentose-phosphate exists in

A. prokaryotic cells
B. eukaryotic cells
C. prokaryotic and eukaryotic cells both
D. none of these

Answer: C

46. Entner – Doudoroff pathway is not found in

A. aerobic prokaryotes
B. anaerobic prokaryotes
C. Both (a) and (b)
D. eukaryotes

Answer: D

47. 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: D

48. 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: D

49. 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: A

50. 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: D

51. Which of the following is responsible for phosphate solubilization?

A. Streptococcus
B. Streptomyces
C. Bacillus
D. Clostridium

Answer: C

53. 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: A

54. Nitrogen fixation is a process that requires

A. energy
B. an anaerobic environment
C. both (a) and (b)
D. an aerobic environment

Answer: C

55. 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: D

56. Radioisotopes are frequently used in the study of cells. Assume a culture of E. coli 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: B