Question 1

The relative concentrations of ATP and ADP control the cellular rates of:

Accepted Answer

A) glycolysis. 
B) oxidative phosphorylation. 
C) pyruvate oxidation. 
D) the citric acid cycle. 
E) All of the above 
A) glycolysis. 
B) oxidative phosphorylation. 
C) pyruvate oxidation. 
D) the citric acid cycle. 
E) All of the above

Question 2

A new compound isolated from mitochondria is claimed to represent a previously unrecognized carrier in the electron transfer chain.It is given the name coenzyme Z.Which line of evidence do you feel is the least conclusive in assigning this compound a position in the electron transfer chain?

Accepted Answer

A) Alternate oxidation and reduction of the mitochondrion-bound coenzyme Z can be readily demonstrated. 
B) Removal of coenzyme Z from the mitochondria results in a decreased rate of oxygen consumption. 
C) The rate of oxidation and reduction of mitochondrion-bound coenzyme is of the same order of magnitude as the overall rate of electron transfer in mitochondria as measured by oxygen consumption. 
D) The reduction potential of Z is between that of two compounds known to participate in the electron transport chain 
E) When added to a mitochondrial suspension,coenzyme Z is taken up very rapidly and specifically by the mitochondria. 
A) Alternate oxidation and reduction of the mitochondrion-bound coenzyme Z can be readily demonstrated. 
B) Removal of coenzyme Z from the mitochondria results in a decreased rate of oxygen consumption. 
C) The rate of oxidation and reduction of mitochondrion-bound coenzyme is of the same order of magnitude as the overall rate of electron transfer in mitochondria as measured by oxygen consumption. 
D) The reduction potential of Z is between that of two compounds known to participate in the electron transport chain 
E) When added to a mitochondrial suspension,coenzyme Z is taken up very rapidly and specifically by the mitochondria.

Question 3

Which one of the following statements about human mitochondria is true?

Accepted Answer

A) About 900 mitochondrial proteins are encoded by nuclear genes. 
B) Mitochondrial genes are inherited from both maternal and paternal sources. 
C) rRNA and tRNA are imported from the cytoplasm and used in mitochondrial 
D) The mitochondrial genome codes for all proteins found in mitochondria. 
E) The mitochondrial genome is not subject to mutations. 
A) About 900 mitochondrial proteins are encoded by nuclear genes. 
B) Mitochondrial genes are inherited from both maternal and paternal sources. 
C) rRNA and tRNA are imported from the cytoplasm and used in mitochondrial 
D) The mitochondrial genome codes for all proteins found in mitochondria. 
E) The mitochondrial genome is not subject to mutations.

Question 4

DCMU is an herbicide that acts by blocking photosynthetic electron flow from photosystem II (PSII)to the cytochrome b6f complex.Predict the effect of DCMU on O2 production and on ATP synthesis in the chloroplasts of plants sensitive to DCMU.

Accepted Answer

DCMU blocks electron flow from

Question 5

Cyclic electron flow in chloroplasts produces:

Accepted Answer

A) ATP and O2,but not NADPH. 
B) ATP,but not NADPH or O2. 
C) NADPH and ATP,but not O2. 
D) NADPH,but not ATP or O2. 
E) O2,but not ATP or NADPH. 
A) ATP and O2,but not NADPH. 
B) ATP,but not NADPH or O2. 
C) NADPH and ATP,but not O2. 
D) NADPH,but not ATP or O2. 
E) O2,but not ATP or NADPH.

Question 6

Some photosynthetic bacteria contain the protein bacteriorhodopsin,which absorbs light and pumps protons out of the cell directly.Briefly describe how such a cell could use bacteriorhodopsin and an H+ATPase to make ATP using light.

Accepted Answer

On exposure to light,bacterior

Question 7

Discuss how "accessory pigments" are able to extend the range of light absorption of the chlorophylls.Name some accessory pigments.

Accepted Answer

Accessory pigments are able to

Question 8

When the $\Delta$G'° of the ATP synthesis reaction is measured on the surface of the ATP synthase enzyme,it was found to be close to zero.Describe briefly why this is so.

Accepted Answer

The enzyme binds ATP more tigh

Question 9

During oxidative phosphorylation,the proton motive force that is generated by electron transport is used to:

Accepted Answer

A) create a pore in the inner mitochondrial membrane. 
B) generate the substrates (ADP and Pi)for the ATP synthase. 
C) induce a conformational change in the ATP synthase. 
D) oxidize NADH to NAD+. 
E) reduce O2 to H2O. 
A) create a pore in the inner mitochondrial membrane. 
B) generate the substrates (ADP and Pi)for the ATP synthase. 
C) induce a conformational change in the ATP synthase. 
D) oxidize NADH to NAD+. 
E) reduce O2 to H2O.

Question 10

Photosynthetic phosphorylation and oxidative phosphorylation appear to be generally similar processes,both consisting of ATP synthesis coupled to the transfer of electrons along an electron carrier chain.Which of the following is not true of both processes?

Accepted Answer

A) Both contain cytochromes and flavins in their electron carrier chains. 
B) Both processes are associated with membranous elements of the cell. 
C) Both use oxygen as a terminal electron acceptor. 
D) Each represents the major route of ATP synthesis in those cells in which it is found. 
E) Protons are pumped from the inside to the outside of both mitochondria and chloroplast membranes 
A) Both contain cytochromes and flavins in their electron carrier chains. 
B) Both processes are associated with membranous elements of the cell. 
C) Both use oxygen as a terminal electron acceptor. 
D) Each represents the major route of ATP synthesis in those cells in which it is found. 
E) Protons are pumped from the inside to the outside of both mitochondria and chloroplast membranes

Question 11

Explain briefly the current model for how the proton motive force that is generated by electron transport is used to drive the ATP synthesis reaction.

Accepted Answer

The enzyme binds ATP more tightly than A

Question 12

Which of the following is not a feature of complex IV?

Accepted Answer

A) Cytochrome c is a one-electron donor. 
B) Oxygen is a substrate. 
C) Copper is an essential metal for the reaction. 
D) For every electron passed to complex IV,two protons are consumed from the matrix (N)side. 
E) In order to generate two water molecules,complex IV must go through the catalytic cycle two times. 
A) Cytochrome c is a one-electron donor. 
B) Oxygen is a substrate. 
C) Copper is an essential metal for the reaction. 
D) For every electron passed to complex IV,two protons are consumed from the matrix (N)side. 
E) In order to generate two water molecules,complex IV must go through the catalytic cycle two times.

Question 13

Which of the following statements about the chemiosmotic theory is correct?

Accepted Answer

A) Electron transfer in mitochondria is accompanied by an asymmetric release of protons on one side of the inner mitochondrial membrane. 
B) It predicts that oxidative phosphorylation can occur,even in the absence of an intact inner mitochondrial membrance. 
C) The effect of uncoupling reagents is a consequence of their ability to carry electrons through membranes. 
D) The membrane ATP synthase has no significant role in the chemiosmotic theory. 
E) All of the above 
A) Electron transfer in mitochondria is accompanied by an asymmetric release of protons on one side of the inner mitochondrial membrane. 
B) It predicts that oxidative phosphorylation can occur,even in the absence of an intact inner mitochondrial membrance. 
C) The effect of uncoupling reagents is a consequence of their ability to carry electrons through membranes. 
D) The membrane ATP synthase has no significant role in the chemiosmotic theory. 
E) All of the above

Question 14

What is an action spectrum,and what do peaks in an action spectrum signify? Show a typical action spectrum plot for photosynthesis.

Accepted Answer

An action spectrum is a plot of the effe

Question 15

Diagram the path of electron flow from NADH to the final electron acceptor during electron transport in mitochondria.For each electron carrier,indicate whether only electrons,or both electrons and protons,are accepted/donated by that carrier.Also,indicate where electrons from succinate oxidation enter the chain of carriers.

Accepted Answer

NADH (both)@#LAT-DLM& FP (both)@#LAT-DLM& Q (both)@#LAT-DLM&cyt b (e<s

Question 16

The light reactions in photosynthetic higher plants:

Accepted Answer

A) do not require chlorophyll. 
B) produce ATP and consume NADH. 
C) require the action of a single reaction center. 
D) result in the splitting of H2O,yielding O2. 
E) serve to produce light so that plants can see underground. 
A) do not require chlorophyll. 
B) produce ATP and consume NADH. 
C) require the action of a single reaction center. 
D) result in the splitting of H2O,yielding O2. 
E) serve to produce light so that plants can see underground.

Question 17

Describe what happens at photosystem I from the point where an antenna chlorophyll molecule absorbs a photon of light to the passage of an electron to NADP+.

Accepted Answer

The antenna chlorophyll molecule passes

Question 18

Mammals produce heat by using the endogenous uncoupling agent:

Accepted Answer

A) the small molecule 2-4-Dinitrophenol synthesized by the cell. 
B) the protein thermogenin. 
C) the protein thioredoxin. 
D) the protein cytochrome c. 
E) a modified form of the FoF1 ATPase. 
A) the small molecule 2-4-Dinitrophenol synthesized by the cell. 
B) the protein thermogenin. 
C) the protein thioredoxin. 
D) the protein cytochrome c. 
E) a modified form of the FoF1 ATPase.

Exam 19: Oxidative Phosphorylation and Photophosphorylation

The relative concentrations of ATP and ADP control the cellular rates of:

A new compound isolated from mitochondria is claimed to represent a previously unrecognized carrier in the electron transfer chain.It is given the name coenzyme Z.Which line of evidence do you feel is the least conclusive in assigning this compound a position in the electron transfer chain?

Which one of the following statements about human mitochondria is true?

DCMU is an herbicide that acts by blocking photosynthetic electron flow from photosystem II (PSII)to the cytochrome b6f complex.Predict the effect of DCMU on O2 production and on ATP synthesis in the chloroplasts of plants sensitive to DCMU.

Cyclic electron flow in chloroplasts produces:

Some photosynthetic bacteria contain the protein bacteriorhodopsin,which absorbs light and pumps protons out of the cell directly.Briefly describe how such a cell could use bacteriorhodopsin and an H+ATPase to make ATP using light.

Discuss how "accessory pigments" are able to extend the range of light absorption of the chlorophylls.Name some accessory pigments.

When the Δ\DeltaΔ G'° of the ATP synthesis reaction is measured on the surface of the ATP synthase enzyme,it was found to be close to zero.Describe briefly why this is so.

During oxidative phosphorylation,the proton motive force that is generated by electron transport is used to:

Photosynthetic phosphorylation and oxidative phosphorylation appear to be generally similar processes,both consisting of ATP synthesis coupled to the transfer of electrons along an electron carrier chain.Which of the following is not true of both processes?

Explain briefly the current model for how the proton motive force that is generated by electron transport is used to drive the ATP synthesis reaction.

Which of the following is not a feature of complex IV?

Which of the following statements about the chemiosmotic theory is correct?

What is an action spectrum,and what do peaks in an action spectrum signify? Show a typical action spectrum plot for photosynthesis.

The light reactions in photosynthetic higher plants:

Describe what happens at photosystem I from the point where an antenna chlorophyll molecule absorbs a photon of light to the passage of an electron to NADP+.

Mammals produce heat by using the endogenous uncoupling agent:

The Foundations of Biochemistry

Water

Amino Acids, peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

Recombinant Dna Technology

Lipids

Biological Membranes and Transport

Biosignaling

Principles of Bioenergetics

Glycolysis, gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, nucleotides, and Related Molecules

Integration and Hormonal Regulation of Mammalian Metabolism

Genes and Chromosomes

Dna Metabolism

Rna Metabolism

Protein Metabolism

Regulation of Gene Expression

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DCMU is an herbicide that acts by blocking photosynthetic electron flow from photosystem II (PSII)to the cytochrome b₆f complex.Predict the effect of DCMU on O₂ production and on ATP synthesis in the chloroplasts of plants sensitive to DCMU.

Some photosynthetic bacteria contain the protein bacteriorhodopsin,which absorbs light and pumps protons out of the cell directly.Briefly describe how such a cell could use bacteriorhodopsin and an H⁺ATPase to make ATP using light.

When the $\Delta$ G'° of the ATP synthesis reaction is measured on the surface of the ATP synthase enzyme,it was found to be close to zero.Describe briefly why this is so.

Describe what happens at photosystem I from the point where an antenna chlorophyll molecule absorbs a photon of light to the passage of an electron to NADP⁺.