Chapter 11 | Catabolism Energy Release And – Test Bank Docx

Prescott's Microbiology, 11e (Willey)

Chapter 11 Catabolism: Energy Release and Conservation

1) The total of all chemical reactions occurring in a cell is called ________.

A) anabolism

B) catabolism

C) metabolism

D) None of the choices are correct.

2) Although most metabolic reactions are freely reversible, a few irreversible catabolic steps are bypassed during biosynthesis with special enzymes that catalyze the reverse reaction in order to allow for independent regulation of catabolic and anabolic pathways.

3) Metabolic pathways can be either catabolic or anabolic but not both.

4) ________ pathways are those that function both catabolically and anabolically.

5) The catabolism of glucose begins with one or more of the glycolytic pathways that yield pyruvate.

6) ________ ________ is a process that can completely catabolize an organic energy source to CO2 using the glycolytic pathways and TCA cycle with O2 as the terminal electron acceptor for an electron transport chain.

7) Very few Gram-positive bacteria utilize the Entner-Doudoroff glycolytic pathway.

8) Some aerobic bacteria lack the Entner-Doudoroff and Embden-Meyerhoff pathways and instead use the pentose phosphate pathway for glycolysis.

9) An organism may use glycolysis and the pentose phosphate pathway simultaneously.

10) The net gain of ATP per molecule of glucose metabolized anaerobically via the Embden-Meyerhof pathway in prokaryotes is ________.

A) 2

B) 36

C) 38

D) 85

11) The net gain of ATP per molecule of glucose metabolized to pyruvate using Entner-Doudoroff pathway is ________.

A) 4

B) 2

C) 1

D) 0

12) The pentose phosphate pathway produces ________.

A) CO2

B) NADPH

C) glyceraldehyde 3-phosphate

D) All of the choices are correct.

13) The synthesis of ATP from ADP and Pi, when coupled with an exergonic chemical reaction is called ________ phosphorylation.

A) chemiosmotic

B) oxidative

C) substrate-level

D) conformational change

14) The most common pathway for conversion of glucose to pyruvate is ________.

A) Entner-Doudoroff

B) Pentose phosphate

C) Embden-Meyerhoff

D) mixed acid fermentation

15) The TCA cycle generates all of the following from each acetyl-CoA molecule oxidized except ________.

A) three NADH molecules

B) two CO2 molecules

C) one FADH2 molecule

D) two ATP or GTP molecules

16) The pyruvate dehydrogenase complex oxidizes and cleaves pyruvate to form one CO2 and ________.

A) lactate

B) isocitric acid

C) acetyl-CoA

D) succinyl-CoA

17) After glycolysis, pyruvate is oxidized to one CO2 and the two-carbon molecule acetyl-CoA by a multienzyme system called the ________ ________ complex.

18) TCA cycle enzymes are found in the ________ ________ of eukaryotic cells.

19) In the TCA cycle, two carbons are removed from citric acid in the form of ________, thereby regenerating oxaloacetate to complete the cycle.

A) acetyl-CoA

B) ethanol

C) carbon dioxide

D) methanol

20) In the TCA cycle, two carbons in the form of ________ are added to oxaloacetate at the start of the cycle.

A) acetyl-CoA

B) ethanol

C) carbon dioxide

D) methanol

21) The major function(s) of the TCA cycle is(are) ________.

A) energy production

B) provision of carbon skeletons for biosynthesis of cell components

C) electron transport

D) energy production and provision of carbon skeletons for biosynthesis of cell components

22) When mitochondria pass electrons donated by NADH through the electron transport chain to molecular oxygen, a theoretical maximum of ________ molecules of ATP can be made per oxygen molecule reduced.

23) The hypothesis that proton motive force drives ATP synthesis is called the ________ hypothesis.

24) The most commonly accepted hypothesis for the production of ATP that results from electron transport system is called the ________ hypothesis.

25) Bacterial electron transport chains may be comprised of fewer components and have lower phosphate to oxygen (P/O) ratios than mitochondrial transport chains.

26) The electron transport systems in eukaryotes and prokaryotes use different electron carriers.

27) In addition to being used in the making of ATP, a proton motive force is used directly to power the rotation of bacterial flagella.

28) Differences between mitochondrial and E. coli electron transport chains include which of the following?

A) The E. coli chain contains a different array of cytochromes.

B) The fundamental principles on which they operate are different.

C) Higher P/O values are observed in E. coli.

D) The electron transport chain does not involve membranes in E. coli.

29) Which of the following is NOT true regarding ATP synthases?

A) They require proton motive force to make ATP.

B) They span the inner membrane of mitochondria.

C) The proton flow is outward during ATP synthesis.

D) The subunits of ATP synthase undergo conformational changes during ATP production.

30) The theoretical maximum net gain of ATP per molecule of glucose metabolized aerobically in eukaryotes is ________.

A) 2

B) 32

C) 38

D) 85

31) Production of ATP using the energy liberated when electrons from reduced chemical bonds are passed through the electron transport system is generally referred to as ________.

A) chemiosmotic

B) respiration

C) substrate-level

D) conformational change

32) Mitochondrial electron transport takes place ________.

A) on the outer mitochondrial membrane

B) on the inner mitochondrial membrane

C) in the fluid matrix of the mitochondria

D) on the outer mitochondrial membrane and on the inner mitochondrial membrane

33) In higher eukaryotes, most aerobically generated ATP is produced by ________.

A) glycolysis

B) the TCA cycle

C) a membrane-bound proton translocating ATP synthase during oxidative phosphorylation

D) All of the choices are correct.

34) The number of ATP molecules generated per atom of oxygen that is reduced when electrons are passed from NADH or reduced FAD (FADH) to O2 is called the ________.

A) utilization ratio

B) energy yield

C) P/O ratio

D) phosphorylation coefficient

35) In aerobic conditions, it takes ________ sugar to produce the same amount of ATP when compared to anaerobic conditions.

A) more

B) less

C) the same amount of

36) Prokaryotes may use several different terminal oxidases for the electron transport system.

37) Reduction of nitrate to nitrite by Paracoccus denitrificans is an example of anaerobic respiration.

38) When cells of a facultative anaerobe such as Paracoccus denitrificans are growing under anaerobic conditions and using nitrate as the terminal electron acceptor, ________ nitrate reduction is occurring.

39) Which of the following can be used as electron acceptors during anaerobic respiration?

A) Nitrate

B) Sulfate

C) Carbon dioxide

D) All of the choices are correct.

40) Organisms that form lactate, ethanol, and CO2 as end products of glucose metabolism are called ________ fermenters.

41) Fermentation involves the use of pyruvate and/or other organic molecules as electron acceptors.

42) In the process of fermentation an organic substrate, such as glucose, is reduced and an intermediate of the pathway, such as pyruvate, is oxidized.

43) Organisms that directly reduce almost all of their pyruvate to lactate are called ________ fermenters.

44) Oxygen is always required for the regeneration of NAD from NADH.

45) Large external polysaccharides are degraded by bacteria and archaea using ________ ________, which they secrete outside the cell.

46) Disaccharides and polysaccharides can be processed as nutrients after first being cleaved to monosaccharides by either ________ or ________.

47) Fatty acids are metabolized by the ________ pathway.

A) alpha-oxidation

B) beta-oxidation

C) gamma-oxidation

D) delta-oxidation

48) During breakdown of fatty acids, carbons are removed ________ at a time with each turn of the cycle, and two carbon units are released as ________.

A) one; carbon dioxide

B) one; methane

C) two; acetyl-CoA

D) two; ethanol

49) Proteins are catabolized by hydrolytic cleavage to amino acids by the action of enzymes called ________.

50) Amino acids are processed first by the removal of the amino group through ________.

A) deamination

B) transamination

C) phosphorolytic cleavage

D) deamination or transamination

51) Nitrification of ammonia occurs when ammonia is first converted to nitrite and then is converted to nitrate by the nitrogen-fixing bacteria.

52) ________ is a two-step process that depends on the activity of at least two genera to carry out the oxidation of ammonia to nitrate.

53) Which of the following may be used as sources of energy by chemolithotrophs?

A) Hydrogen gas

B) Reduced nitrogen compounds

C) Reduced sulfur compounds

D) All of the choices are correct.

54) How many molecules of ATP are needed to reduce one molecule of carbon dioxide to carbohydrate by oxygenic phototrophs during the dark reactions of photosynthesis?

A) 2

B) 3

C) 4

D) 10–12

55) How many molecules of NADPH are needed to reduce one molecule of carbon dioxide to carbohydrate by oxygenic phototrophs during the dark reactions of photosynthesis?

A) 2

B) 3

C) 4

D) 10–12

56) How many quanta of light are needed to reduce one molecule of carbon dioxide to carbohydrate during photosynthesis?

A) 2

B) 3

C) 4

D) 10–12

57) All prokaryotic photosynthesizers are anoxygenic.

58) Photosynthetic organisms serve as the base for most food chains in the biosphere.

59) All eukaryotic photosynthesizers are oxygenic.

60) In the process of noncyclic photophosphorylation, ________.

A) water is split to form oxygen gas

B) electrons from water flow through electron transport chains resulting in synthesis of ATP and NADPH

C) photosystems I and II are both required

D) All of the choices are correct.

61) In the process of ________, ATP is synthesized when excited electrons from chlorophyll P700 pass through a series of electron carriers then return to chlorophyll P700.

A) photosynthesis

B) cyclic photophosphorylation

C) acyclic photophosphorylation

D) noncyclic photophosphorylation

62) Photosynthetic electron transport in cyanobacteria takes place ________.

A) on the plasma membrane

B) in the chloroplast

C) in the cytoplasm

D) on the thylakoid membranes

63) Select the terms that describe an organism's carbon source.

A) Heterotroph

B) Lithotroph

C) Chemotroph

D) Autotroph

E) Organotroph

64) The terms phototroph and chemotroph refer to an organism's source of ________.

A) energy

B) electrons

C) carbon

D) nitrogen

65) A newly described bacterial species has been shown to use CO2 as its carbon source. Its energy source and its source of reducing power (electrons) are inorganic chemicals. Which term would best describe this nutritional type?

A) Chemolithoheterotroph

B) Photoorganoheterotroph

C) Photolithoheterotroph

D) Chemolithoautotroph

66) Which nutritional classification would you predict to fit most of the well-known members of the human microbiome?

A) Photolithoautotrophs

B) Chemoorganoheterotrophs

C) Chemolithoautotrophs

D) Chemolithohetertrophs

67) Processes that supply ATP, reducing power, and precursor metabolites are collectively referred to as ________ reactions.

A) redox

B) fueling

C) synthetic

D) generating

68) In most cases, fueling reactions are ________ reactions.

A) catabolic

B) anabolic

C) reducing

D) synthesizing

69) An organism can fit into only one nutritional pattern, such as photoheterotrophy, and cannot change if the environmental conditions change.

70) An organism can take advantage of energy available from both light and from organic molecules and exhibit both phototrophy and chemoorganotrophy.

71) Indicate the processes below that represent the basic types of chemoorganotrophic metabolism.

A) Photosynthesis

B) Aerobic respiration

C) Fermentation

D) Oxidation-reduction

E) Anaerobic respiration

72) Aerobic respiration, anaerobic respiration, and fermentation are the three basic types of ________.

A) chemoorganoheterotrophic metabolism

B) photolithoautotrophic metabolism

C) chemolithoautotrophic metabolism

D) chemoorganoautotrophic metabolism

73) Glycolysis and the TCA cycle are two of the most important catabolic pathways in chemoorganotrophs.

74) What distinguishing feature characterizes aerobic and anaerobic respiration but does not play a role in fermentation pathways?

A) Oxidation-reduction reactions

B) Hydrolysis reactions

C) The absence of O2

D) The presence of an electron transport chain

75) The six carbons of the glucose molecule that enter the cell respiration pathway end up in/as ________  ______ by the end of the process.

76) Indicate the products of aerobic respiration.

A) Water

B) O2

C) CO2

D) NADH

E) ATP

F) All of the choices are correct.

77) Which of the following produces the most ATP during aerobic respiration?

A) Glycolysis

B) TCA cycle

C) Fermentation

D) Electron transport chain and chemiosmosis

E) Substrate level phosphorylation

78) During glycolysis, ATP is produced when 1,3 bisphosphoglycerate transfers a phosphate to ADP forming ATP.  This is an example of ________.

A) photophosphorylation

B) oxidative phosphorylation

C) substrate-level phosphorylation

D) glycolytic phosphorylation

79) In order for a substance to transfer a phosphate to ADP in a substrate-level phosphorylation reaction, which of the following must be true?

A) The phosphate donor must have a lower phosphate transfer potential than ATP.

B) The phosphate donor must have a higher oxidation-reduction potential than ATP.

C) The phosphate donor must have a higher phosphate transfer potential than ATP.

D) The phosphate donor must have a lower oxidation-reduction potential than ATP.

80) Whereas the Embden-Meyerhof pathway produces two molecules of pyruvate (net) for each glucose, the Entner-Doudoroff pathway produces one molecule each of ________ and ________.

81) Which of the following is the major glycolytic pathway used by plants and animals?

A) Tricarboxylic acid cycle

B) Embden-Meyerhof pathway

C) Entner-Doudoroff pathway

D) Pentose phosphate pathway

82) The pentose phosphate pathway is the major glycolytic pathway used by archaea.

83) Which of the following names refer to the tricarboxlic acid cycle?  

A) Krebs cycle

B) Pentose phosphate pathway

C) Calvin cycle

D) Citric acid cycle

E) Cyclic phosphorylation

84) The terms Krebs cycle, tricarboxylic acid cycle, and citric acid cycle all refer to the same process.

85) Which of the following is produced in largest numbers by the TCA cycle?

A) ATP (GTP)

B) NADH

C) FADH

D) CO2

86) The TCA cycle is located in the ________ of bacteria, and in the ________ of eukaryotes.

A) cytoplasm; mitochondrial matrix

B) plasma membrane; inner mitochondrial membrane

C) plasma membrane; mitochondrial matrix

D) cytoplasm; inner mitochondrial membrane

87) The major difference between aerobic and anaerobic respiration is the final electron acceptor at the end of the electron transport chain.

88) When nitrate is used as a final electron acceptor by bacteria growing in anoxic soils, the nitrogen is no longer available for the construction of precursor metabolites.  This is referred to as ________.

A) nitrification

B) nitrogen fixation

C) nitrogen respiration

D) dissimilatory nitrate reduction

89) The amount of ATP produced during anaerobic respiration is ________ that produced during aerobic respiration, because the difference in the standard reduction potential between NADH and the final electron acceptor is ________.

A) less than; larger

B) less than; smaller

C) greater than; larger

D) greater than; smaller

90) Which of the following are consequences of anaerobic respiration?  (Check all that apply.)

A) Some bacteria are able to readily survive in both well-oxygenated as well as anoxic environments.

B) Some bacteria may cause denitrification.

C) Some bacteria are able to perform nitrogen fixation.

D) Bacteria are able to reduce the levels of  NO3− in sewage plant effluents.

91) How is ATP produced during fermentation?

A) Cyclic phosphorylation

B) Substrate-level phosphorylation

C) Oxidative phosphorylation

D) Use of proton motive force to drive ATP synthase

E) Chemosynthetic phosphorylation

92) How does a fermenter generate proton motive force (PMF) to drive active transport?

A) Fermenters use an electron transport chain for this purpose.

B) Fermenters cannot generate proton motive force.

C) Fermenters can reverse the direction of the ATP synthase to generate PMF.

93) How does the phosphorylation of galactose differ from the phosphorylation of glucose, mannose, and fructose prior to catabolism?

A) Phosphorylation of galactose requires NADPH to phosphorylate galactose-1-phosphate

B) Phosphorylation of galactose requires PEP (phosphoenolpyruvate) to phosphorylate galactose-1-phosphate

C) Phosphorylation of galactose requires ATP to phosphorylate galactose-1-phosphate

D) Phosphorylation of galactose requires TTP to phosphorylate galactose-1-phosphate

E) Phosphorylation of galactose requires UTP to phosphorylate galactose-1-phosphate

94) Complete catabolism of lactose requires ________.

A) ATP, NAD, and appropriate enzymes

B) ATP, UTP, NAD, and appropriate enzymes

C) NAD and appropriate enzymes

95) What enzymes hydrolyze proteins, releasing amino acids?

A) Tranaminases

B) Proteases

C) Decarboxylases

D) Deaminases

96) A ________ hydrolyzes a protein into its constituent amino acid monomers and a ________ enzyme removes amino groups from the amino acids.

97) ________ refers to the removal of an amino group from an amino acid. One mechanism for this removal is ________, in which the amino group is transferred to an acceptor molecule.

A) Deamination; hydrolysis

B) Deamination; transamination

C) Transamination; deamination

D) Hydrolysis; transamination

98) The substances that donate electrons to the electron transport chains of chemolithotrophs are ________.

A) carbohydrates

B) inorganic compounds

C) lipids

D) methane gas and alcohols

99) Most chemolithotrophs have electron transport chains that terminate with O2 as the final electron acceptor.

100) Many chemolithotrophs are able to produce more ATP from oxidation of their inorganic energy source than chemoheterotrophs produce from the aerobic oxidation of glucose.

101) Chemolithotrophs generally derive ________ ATP from oxidation of inorganic substrates because the reduction potentials of those substrates are much more ________ than the reduction potential of organic substrates.

A) more; positive

B) more; negative

C) less; positive

D) less; negative

102) ________ is an aerobic chemolithotrophic process that ultimately oxidizes ammonia to nitrate, whereas ________ is a form of anaerobic respiration involving the oxidation of an organic compound using an oxidized nitrogenous compound, such as nitrate, as the terminal electron acceptor.

A) Ammonification; nitrification

B) Denitrification; nitrification

C) Ammonification; denitrification

D) Nitrification; denitrification

103) All forms of phototropy "harvest" light energy to fix carbon, producing sugar.

104) Photoheterotrophs that use light to generate ATP, but do not fix CO2 ________. (Check all that apply.)

A) would best be described as photosynthetic

B) would use both the light reactions and the Calvin cycle

C) would use neither the light reactions nor the Calvin cycle

D) would best be described as phototropic

E) would use the light reactions but not the Calvin cycle

105) Chlorophyll a and chlorophyll b as well as the accessory pigments are arranged in an antenna array with a reaction center chlorophyll.  These antenna arrays with the reaction center chlorophyll are known as ________.

A) reaction center systems

B) photomembrane systems

C) photosystems

D) Calvin systems

106) Which of the following described roles attributed to accessory pigments such as carotenes and phycobiliproteins?  (Check all that apply.)

A) These pigments absorb light in ranges not absorbed by chlorophylls and transfer the energy to chlorophylls.

B) These pigments extend the spectrum of wavelengths that will drive photosynthesis.

C) The accessory pigments are involved in maintaining the Calvin cycle.

D) Accessory pigments protect organisms from potentially damaging intense sunlight.

107) In what ways are oxidative phosphorylation and photophosphorylation similar?

A) The source of energy is highly reduced organic compounds

B) An electron transport chain is used

C) Proton motive force is generated

D) Water is split to provide electrons

E) ATP synthase enzyme phosphorylates ADP to make ATP

108) Consider the metabolism of a chlorophyll–based phototroph. In oxidative phosphorylation during cell respiration, the source of energy is ________ whereas in photophosphorylation the source of energy is ________.

A) highly reduced organic compounds; light

B) NADH; NADPH

C) electron transport chain; chlorophyll

D) ATP; light

109) The Embden-Meyerhof, Entner-Doudoroff and pentose phosphate pathways all bring about the reduction of coenzymes (either NAD+ or NADP+). The reduced coenzymes ________.

A) provide reducing power to fuel subsequent reactions

B) are converted into ATP for energy

C) serve as precursor molecules for anabolic reactions

D) can no longer be oxidized

110) The TCA cycle ________.

A) provides reducing power in the form of NADH and FADH2, and precursor molecules for anabolic reactions

B) yields 34 molecules of ATP

C) produces pyruvate as a source of electrons to drive the electron transport chain

D) is a divergent pathway that produces ATP and CO2

111) The TCA cycle begins when ________.

A) pyruvate from the glycolytic pathway is oxidized to acetyl-CoA, which is added to oxaloacetate

B) NADH is oxidized to NAD+, which provides a source of electrons to drive the cycle

C) ATP from the glycolytic pathway is hydrolyzed, providing the energy to start the cycle

D) pyruvate from the glycolytic pathway is added to oxaloacetate

112) Oxidative decarboxylation takes place when pyruvate from the glycolytic pathway is oxidized, producing acetyl-CoA along with one CO2 and one NADH.

113) Which of the following statements is true regarding the effect of electron transport chain length on energy production?

A) As electrons are passed from carrier to carrier, each oxidation releases enough energy to actively transport protons across a membrane, thus, the more carriers, the greater the proton motive force produced.

B) The length of the electron transport chain does not play a role in the magnitude of the proton motive force produced.

C) The longer the electron transport chain, the less energy is stored in the proton motive force, since energy must be expended when passing electrons down the chain.

D) Bacterial and archaeal electron transport chains are the same as eukaryotic chains, so the same amount of energy is produced from the resulting proton motive force, regardless of the organism.

114) The oxidation of glucose to CO2 and H2O with the subsequent production of energy is best reflected in which of the following statements?

A) Glucose is oxidized in a stepwise fashion beginning with a glycolytic pathway and continuing with the TCA cycle where the remainder of the energy from the glucose is harnessed in reduced coenzymes, which transport electrons to an electron transport chain where ATP is made by oxidative phosphorylation.

B) Glucose is reduced in a stepwise fashion beginning with the Entner-Doudoroff pathway and continuing with the TCA cycle where 38 molecules of ATP are made by oxidative phosphorylation.

C) Glucose is oxidized in a stepwise fashion beginning with the Enbden-Meyerhof pathway and continuing with the TCA cycle where the remainder of the energy from the glucose is harnessed in oxidized coenzymes, which transport electrons to an electron transport chain where ATP is made by substrate-level phosphorylation.

D) Glucose is reduced in a stepwise fashion beginning with the TCA cycle and continuing with a glycolytic pathway where the remainder of the energy from the glucose is harnessed in oxidized coenzymes, which transport electrons to an electron transport chain where ATP is made by oxidative phosphorylation.

115) The catabolism of glucose through a glycolytic pathway, followed by the TCA cycle and culminating in ATP production via the formation of a proton motive force in the electron transport chain, represents the overall reduction of glucose.

116) The energy source for substrate-level phosphorylation (SLP) differs from that of oxidative phosphorylation (OP) in that ________.

A) OP is driven using energy provided by a proton motive force, whereas the energy to add a phosphate group to ADP during SLP comes from the direct transfer of a phosphate group from a molecule with a higher phosphate transfer potential than ATP

B) SLP is driven using energy provided by a proton motive force, whereas the energy to add a phosphate group to ADP during OP comes from the direct transfer of a phosphate group from a molecule with a higher phosphate transfer potential than ATP

C) OP is driven using energy provided by a proton motive force, whereas the energy to add a phosphate group to ADP during SLP comes from the direct transfer of a phosphate group from a molecule with a lower phosphate transfer potential than ATP

D) SLP  is driven using energy provided by a proton motive force, whereas the energy to remove a phosphate group from ATP during OP comes from the direct transfer of a phosphate group from a molecule with a lower phosphate transfer potential than ATP

117) Chemolithotrophs obtain their energy from ________.

A) inorganic molecules that are oxidized, providing electrons to create a proton motive force that drives oxidative phosphorylation

B) inorganic molecules that directly transfer a phosphate group to ATP during substrate-level phosphorylation

C) organic molecules that are oxidized via a glycolytic pathway and the TCA cycle

D) inorganic molecules that are reduced, providing electrons to create a proton motive force that drives oxidative phosphorylation

118) Which statement best describes the concept of electron bifurcation?

A) A flavoenzyme oxidizes an electron donor and directs two electrons to two different recipients, one being an exothermic reduction that pulls the simultaneous endothermic reduction to completion.

B) A flavoenzyme oxidizes an electron donor and directs two electrons down a series of carriers creating a proton motive force.

C) A flavoenzyme oxidizes an electron donor and directs two electrons to a single, more electronegative recipient that releases energy for the production of ATP.

D) A flavoenzyme reduces an electron donor and directs two electrons to two different recipients, one being an exothermic oxidation that pulls the simultaneous endothermic oxidation to completion.

119) Flavoenzymes oxidize an electron donor then direct the two electrons to two different recipients having different reduction potentials.

120) Endergonic reactions in cells do not happen spontaneously, that is, they require an input of energy. Coupling such reactions with exothermic ones, such as the hydrolysis of ATP drives the reaction forward. Certain organisms are able to bypass the need for ATP or a proton motive force by ________.

A) tightly coupling an endergonic and an exergonic reduction so the exergonic reduction can drive the completion of the endergonic one in a process known as electron bifurcation

B) tightly coupling an endergonic and an exergonic oxidation so the endergonic oxidation can drive the completion of the exergonic one in a process known as electron bifurcation

C) using glucose as a direct source of energy in a process similar to spontaneous combustion

D) circumventing the need for endergonic reactions

121) Electron bifurcation is a useful way for organisms to circumvent the need for ATP hydrolysis and/or a proton motive force because it tightly couples reactions that are thermodynamically unfavorable with those that occur spontaneously, providing an excess of energy to drive the former.