Question 1

Which of the following statements about the light reactions in photosynthetic plants is false?

Accepted Answer

A)  A membrane-bound ATPase couples ATP synthesis to electron transfer.
B)  No CO2 is fixed in the light reactions.
C)  The ultimate electron acceptor is O2.
D)  The ultimate source of electrons for the process is H2O.
E)  There are two distinct photosystems,linked together by an electron transfer chain.F) B) and E)
G) B) and C)

Question 2

Oxidative phosphorylation and photophosphorylation share all of the following except:

Accepted Answer

A)  chlorophyll.
B)  involvement of cytochromes.
C)  participation of quinones.
D)  proton pumping across a membrane to create electrochemical potential.
E)  use of iron-sulfur proteins.F) A) and E)
G) B) and C)

Question 3

The rate of oxidative phosphorylation in mitochondria is controlled primarily by:

Accepted Answer

A)  feedback inhibition by CO2.
B)  the availability of NADH from the TCA cycle.
C)  the concentration of citrate (or) the glycerol-3-phosphate shuttle.
D)  the mass-action ratio of the ATD-ADP system.
E)  the presence of thermogenin.F) A) and D)
G) D) and E)

Question 4

In the reoxidation of QH2 by purified ubiquinone-cytochrome c reductase (Complex III) from heart muscle,the overall stoichiometry of the reaction requires 2 mol of cytochrome c per mole of QH2 because:

Accepted Answer

A)  cytochrome c is a one-electron acceptor,whereas QH2 is a two-electron donor.
B)  cytochrome c is a two-electron acceptor,whereas QH2 is a one-electron donor.
C)  cytochrome c is water soluble and operates between the inner and outer mitochondrial membranes
D)  heart muscle has a high rate of oxidative metabolism,and therefore requires twice as much cytochrome c as QH2 for electron transfer to proceed normally.
E)  two molecules of cytochrome c must first combine physically before they are catalytically active.F) C) and D)
G) A) and C)

Question 5

During photophosphorylation in plants,electrons flow through a series of carriers in the chloroplast.What is the ultimate donor of electrons,and what is the ultimate acceptor? What provides the energy to move those electrons?

Accepted Answer

The ultimate donor is H₂O,and t...

Question 6

Which one of the following is true about reaction centers?

Accepted Answer

A)  Cyanobacteria and plants have two reaction centers arranged in tandem.
B)  Cyanobacteria contain a single reaction center of the Fe-S type.
C)  Green sulfur bacteria have two reaction centers arranged in tandem.
D)  Plant photosystems have a single reaction center of the pheophytin-quinone type.
E)  Purple bacteria contain a single reaction center of the Fe-S type.F) A) and E)
G) A) and D)

Question 7

Which of the following electron carriers is not able to transfer one electron at a time?

Accepted Answer

A)  NADH
B)  FMN
C)  FAD
D)  Ubiquinone
E)  HemeF) All of the above
G) B) and E)

Question 8

Discuss three lines of evidence that support the theory that mitochondria evolved from endosymbiontic bacteria.

Accepted Answer

1)Modern prokaryotes have respiratory ch...

Question 9

Which of the following is correct concerning the mitochondrial ATP synthase?

Accepted Answer

A)  It can synthesize ATP after it is extracted from broken mitochondria.
B)  It catalyzes the formation of ATP even though the reaction has a large positive  Δ\DeltaΔ  G'°.
C)  It consists of Fo and F1 subunits,which are transmembrane (integral) polypeptides.
D)  It is actually an ATPase and only catalyzes the hydrolysis of ATP.
E)  When it catalyzes the ATP synthesis reaction,the  Δ\DeltaΔ  G'° is actually close to zero. F) C) and D)
G) B) and E)

Question 10

Although molecular oxygen (O2)does not participate directly in any of the reactions of the citric acid cycle,the cycle operates only when O2 is present.Explain this observation.

Accepted Answer

The citric acid cycle produces NADH,whic...

Question 11

During electron transfer through the mitochondrial respiratory chain,the overall reaction is:
NADH + 1/2 O2 + H+ $\rightarrow$ NAD+ + H2O.The difference in reduction potentials for the two half-reactions ($\Delta$E'°)is +1.14 V.Show how you would calculate the standard free-energy change,$\Delta$G'°,for the reaction as written above.(The Faraday constant,,is 96.48 kJ/V·mol. )

Accepted Answer

G'° = -n

E'° = (-2)(9...

Question 12

Which of the following is not found in modern cyanobacteria?

Accepted Answer

A)  PSI
B)  PSII
C)  NADH dehydrogenase complex I
D)  Oxygen-reducing complex IV
E)  MitochondriaF) B) and D)
G) C) and E)

Question 13

Describe and explain the two different ratios that affect the rate of respiration in mitochondria.What is accomplished by these control mechanisms?

Accepted Answer

The acceptor control ratio describes how...

Question 14

Which of the following is not controlled by hypoxia-inducible factor (HIF-1) ?

Accepted Answer

A)  Glucose transport
B)  Glycolysis
C)  Citric acid cycle
D)  Compex I of the respiratory chain
E)  Complex IV of the respiratory chainF) C) and D)
G) B) and C)

Question 15

Place the following electron-carriers into the proper order as found in plant chloroplasts.
 1) Cytochrome b6f complex
2) P680
3) P700
4) Plastocyanin
5) NADPH

Accepted Answer

A)  2,1,3,4,5
B)  2,4,3,1,5
C)  3,1,4,2,5
D)  2,1,4,3,5
E)  3,4,2,1,5F) B) and E)
G) B) and D)

Question 16

For each of the following explain whether they are transported into or out of the mitochondrion and comment briefly on the mechanism for each:
(1)NADH
(2)Inorganic phosphate
(3)ADP

Accepted Answer

NADH produced by glycolysis is indirectl...

Question 17

The standard reduction potential for ubiquinone (Q or coenzyme Q)is 0.045 V,and the standard reduction potential (E'°)for FAD is -0.219 V.Using these values,show that the oxidation of FADH2 by ubiquinone theoretically liberates enough energy to drive the synthesis of ATP.The Faraday constant,,is 96.48 kJ/V·mol.$\Delta$G'° for ATP synthesis is +30.5 kJ/mol.

Accepted Answer

<img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30">E'° = E'°(oxidant)- E'°(reductant)= 0.04...

Question 18

Upon the addition of 2,4-dinitrophenol (DNP) to a suspension of mitochondria carrying out oxidative phosphorylation linked to the oxidation of malate,all of the following occur except:

Accepted Answer

A)  oxygen consumption decreases.
B)  oxygen consumption increases.
C)  the P/O ratio drops from a value of approximately 2.5 to 0.
D)  the proton gradient dissipates.
E)  the rate of transport of electrons from NADH to O2 becomes maximal.F) A) and E)
G) A) and B)

Question 19

The skunk cabbage (Symphocarpus foetidus)can maintain a temperature of 10-25 °C higher than the temperature of the surrounding air.Suggest a mechanism for this.

Accepted Answer

One possible heat-generating mechanism i...

Question 20

Mutations in mitochondrial genes play a role in each of the following diseases except:

Accepted Answer

A)  adult onset diabetes.
B)  cystic fibrosis.
C)  hypertrophic cardiomyopathy.
D)  Leber's hereditary optic neuropathy.
E)  myoclonic epilepsy.F) None of the above
G) All of the above

Exam 19: Oxidative Phosphorylation and Photophosphorylation

Which of the following statements about the light reactions in photosynthetic plants is false?

Correct Answer
verified

Oxidative phosphorylation and photophosphorylation share all of the following except:

Correct Answer
verified

Correct Answer
verified
G'° = -nE'° = (-2)(9...
View Answer

Which of the following electron carriers is not able to transfer one electron at a time?

Correct Answer
verified

The skunk cabbage (Symphocarpus foetidus)can maintain a temperature of 10-25 °C higher than the temperature of the surrounding air.Suggest a mechanism for this.

Correct Answer
verified
One possible heat-generating mechanism i...
View Answer

Although molecular oxygen (O₂)does not participate directly in any of the reactions of the citric acid cycle,the cycle operates only when O₂ is present.Explain this observation.

Correct Answer
verified
The citric acid cycle produces NADH,whic...
View Answer

Mutations in mitochondrial genes play a role in each of the following diseases except:

Correct Answer
verified

The rate of oxidative phosphorylation in mitochondria is controlled primarily by:

Correct Answer
verified

Which of the following is correct concerning the mitochondrial ATP synthase?

Correct Answer
verified

For each of the following explain whether they are transported into or out of the mitochondrion and comment briefly on the mechanism for each: (1)NADH (2)Inorganic phosphate (3)ADP

Correct Answer
verified
NADH produced by glycolysis is indirectl...
View Answer

Discuss three lines of evidence that support the theory that mitochondria evolved from endosymbiontic bacteria.

Correct Answer
verified
1)Modern prokaryotes have respiratory ch...
View Answer

Correct Answer
verified
E'° = E'°(oxidant)- E'°(reductant)= 0.04...
View Answer

Which of the following is not found in modern cyanobacteria?

Correct Answer
verified

Which one of the following is true about reaction centers?

Correct Answer
verified

Describe and explain the two different ratios that affect the rate of respiration in mitochondria.What is accomplished by these control mechanisms?

Correct Answer
verified
The acceptor control ratio describes how...
View Answer

Upon the addition of 2,4-dinitrophenol (DNP) to a suspension of mitochondria carrying out oxidative phosphorylation linked to the oxidation of malate,all of the following occur except:

Correct Answer
verified

Which of the following is not controlled by hypoxia-inducible factor (HIF-1) ?

Correct Answer
verified

In the reoxidation of QH₂ by purified ubiquinone-cytochrome c reductase (Complex III) from heart muscle,the overall stoichiometry of the reaction requires 2 mol of cytochrome c per mole of QH₂ because:

Correct Answer
verified

During photophosphorylation in plants,electrons flow through a series of carriers in the chloroplast.What is the ultimate donor of electrons,and what is the ultimate acceptor? What provides the energy to move those electrons?

Correct Answer
verified
The ultimate donor is H₂O,and t...
View Answer

Place the following electron-carriers into the proper order as found in plant chloroplasts. 1) Cytochrome b₆f complex 2) P680 3) P700 4) Plastocyanin 5) NADPH

Correct Answer
verified

Exam 19: Oxidative Phosphorylation and Photophosphorylation

Which of the following statements about the light reactions in photosynthetic plants is false?

Correct AnswerverifiedShow Answer

Oxidative phosphorylation and photophosphorylation share all of the following except:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedG'° = -nE'° = (-2)(9...View AnswerShow Answer

Which of the following electron carriers is not able to transfer one electron at a time?

Correct AnswerverifiedShow Answer

The skunk cabbage (Symphocarpus foetidus)can maintain a temperature of 10-25 °C higher than the temperature of the surrounding air.Suggest a mechanism for this.

Correct AnswerverifiedOne possible heat-generating mechanism i...View AnswerShow Answer

Although molecular oxygen (O2)does not participate directly in any of the reactions of the citric acid cycle,the cycle operates only when O2 is present.Explain this observation.

Correct AnswerverifiedThe citric acid cycle produces NADH,whic...View AnswerShow Answer

Mutations in mitochondrial genes play a role in each of the following diseases except:

Correct AnswerverifiedShow Answer

The rate of oxidative phosphorylation in mitochondria is controlled primarily by:

Correct AnswerverifiedShow Answer

Which of the following is correct concerning the mitochondrial ATP synthase?

Correct AnswerverifiedShow Answer

For each of the following explain whether they are transported into or out of the mitochondrion and comment briefly on the mechanism for each: (1)NADH (2)Inorganic phosphate (3)ADP

Correct AnswerverifiedNADH produced by glycolysis is indirectl...View AnswerShow Answer

Discuss three lines of evidence that support the theory that mitochondria evolved from endosymbiontic bacteria.

Correct Answerverified1)Modern prokaryotes have respiratory ch...View AnswerShow Answer

Correct AnswerverifiedE'° = E'°(oxidant)- E'°(reductant)= 0.04...View AnswerShow Answer

Which of the following is not found in modern cyanobacteria?

Correct AnswerverifiedShow Answer

Which one of the following is true about reaction centers?

Correct AnswerverifiedShow Answer

Describe and explain the two different ratios that affect the rate of respiration in mitochondria.What is accomplished by these control mechanisms?

Correct AnswerverifiedThe acceptor control ratio describes how...View AnswerShow Answer

Upon the addition of 2,4-dinitrophenol (DNP) to a suspension of mitochondria carrying out oxidative phosphorylation linked to the oxidation of malate,all of the following occur except:

Correct AnswerverifiedShow Answer

Which of the following is not controlled by hypoxia-inducible factor (HIF-1) ?

Correct AnswerverifiedShow Answer

In the reoxidation of QH2 by purified ubiquinone-cytochrome c reductase (Complex III) from heart muscle,the overall stoichiometry of the reaction requires 2 mol of cytochrome c per mole of QH2 because:

Correct AnswerverifiedShow Answer

During photophosphorylation in plants,electrons flow through a series of carriers in the chloroplast.What is the ultimate donor of electrons,and what is the ultimate acceptor? What provides the energy to move those electrons?

Correct AnswerverifiedThe ultimate donor is H2O,and t...View AnswerShow Answer

Place the following electron-carriers into the proper order as found in plant chloroplasts. 1) Cytochrome b6f complex 2) P680 3) P700 4) Plastocyanin 5) NADPH

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
G'° = -nE'° = (-2)(9...
View Answer

Correct Answer
verified

Correct Answer
verified
One possible heat-generating mechanism i...
View Answer

Although molecular oxygen (O₂)does not participate directly in any of the reactions of the citric acid cycle,the cycle operates only when O₂ is present.Explain this observation.

Correct Answer
verified
The citric acid cycle produces NADH,whic...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
NADH produced by glycolysis is indirectl...
View Answer

Correct Answer
verified
1)Modern prokaryotes have respiratory ch...
View Answer

Correct Answer
verified
E'° = E'°(oxidant)- E'°(reductant)= 0.04...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The acceptor control ratio describes how...
View Answer

Correct Answer
verified

Correct Answer
verified

In the reoxidation of QH₂ by purified ubiquinone-cytochrome c reductase (Complex III) from heart muscle,the overall stoichiometry of the reaction requires 2 mol of cytochrome c per mole of QH₂ because:

Correct Answer
verified

Correct Answer
verified
The ultimate donor is H₂O,and t...
View Answer

Place the following electron-carriers into the proper order as found in plant chloroplasts. 1) Cytochrome b₆f complex 2) P680 3) P700 4) Plastocyanin 5) NADPH

Correct Answer
verified