Question 1

Which of the following components of the electron-transport chain does NOT act as a proton pump?

Accepted Answer

A) NADH dehydrogenase 
B) cytochrome c 
C) cytochrome c reductase 
D) cytochrome c oxidase 
A) NADH dehydrogenase 
B) cytochrome c 
C) cytochrome c reductase 
D) cytochrome c oxidase

Question 2

Use the terms provided below to fill in the blanks.Not all words or phrases will be used; each word or phrase may be used more than once.
$\begin{array}{lll}
\text { benzene } & \text { longer } & \text { porphyrin } \
\text { blue } & \text { orange } & \text { red } \
\text { electrons } & \text { photons } & \text { shorter } \
\text { heme } & &
\end{array}$

Photons from sunlight that are in the __________ wavelength range are preferentially absorbed by chlorophyll molecules to raise the energy levels of electrons in the __________ ring.The __________ reflected are lower in energy, which is indicated in the ________, green wavelengths detected by the human eye.

Accepted Answer

Photons from sunlight that are in the re

Question 3

NADH contains a high-energy bond that, when cleaved, donates a pair of electrons to the electron-transport chain.What are the immediate products of this bond cleavage?

Accepted Answer

A) NAD+ + OH− 
B) NAD+ + H− 
C) NAD− + H+ 
D) NAD + H 
A) NAD+ + OH− 
B) NAD+ + H− 
C) NAD− + H+ 
D) NAD + H

Question 4

Compare and contrast the process of reducing N2 to NH3 in Methanococcus jannaschii to the reduction of O2 to H20 in the mitochondrial matrix.What inferences can you draw with respect to the early evolution of energy-generating systems.

Accepted Answer

Methanococcus jannaschii fixes nitrogen

Question 5

What is the source of protons that are pumped out of the mitochondrial matrix in Stage 1 of oxidative phosphorylation?

Accepted Answer

A) NADH 
B) H2O 
C) FADH 
D) H2S 
A) NADH 
B) H2O 
C) FADH 
D) H2S

Question 6

Explain how the diffusion of ubiquinone in three dimensions is restricted in order to ensure its proximity to the other enzyme complexes for the rapid transfer of electrons?

Accepted Answer

Ubiquinone is a membrane-anchored protei

Question 7

Which of the following is NOT part of the process known as "oxidative phosphorylation"?

Accepted Answer

A) Molecular oxygen serves as a final electron acceptor. 
B) FADH2 and NADH become oxidized as they transfer a pair of electrons to the electron-transport chain. 
C) The electron carriers in the electron-transport chain toggle between reduced and oxidized states as electrons are passed along. 
D) ATP molecules are produced in the cytosol as glucose is converted into pyruvate. 
A) Molecular oxygen serves as a final electron acceptor. 
B) FADH2 and NADH become oxidized as they transfer a pair of electrons to the electron-transport chain. 
C) The electron carriers in the electron-transport chain toggle between reduced and oxidized states as electrons are passed along. 
D) ATP molecules are produced in the cytosol as glucose is converted into pyruvate.

Question 8

Ubiquinone is one of two mobile electron carriers in the electron-transport chain.Where does the additional pair of electrons reside in the reduced ubiquinone molecule?

Accepted Answer

A) The electrons are added directly to the aromatic ring. 
B) The electrons are added to each of two ketone oxygens on the aromatic ring. 
C) The electrons are added to the hydrocarbon tail, which hides them inside the membrane bilayer. 
D) Both electrons, and one proton, are added to a single ketone oxygen bound to the aromatic ring. 
A) The electrons are added directly to the aromatic ring. 
B) The electrons are added to each of two ketone oxygens on the aromatic ring. 
C) The electrons are added to the hydrocarbon tail, which hides them inside the membrane bilayer. 
D) Both electrons, and one proton, are added to a single ketone oxygen bound to the aromatic ring.

Question 9

NADH and FADH2 carry high-energy electrons that are used to power the production of ATP in the mitochondria.These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle.Which molecule below can produce the most ATP? Explain your answer.

Accepted Answer

A) NADH from glycolysis 
B) FADH2 from the fatty acid cycle 
C) NADH from the citric acid cycle 
D) FADH2 from the citric acid cycle 
A) NADH from glycolysis 
B) FADH2 from the fatty acid cycle 
C) NADH from the citric acid cycle 
D) FADH2 from the citric acid cycle

Question 10

Which of the following statements is TRUE?

Accepted Answer

A) Ubiquinone is a small, hydrophobic protein containing a metal group that acts as an electron carrier. 
B) A 2Fe2S iron-sulfur center carries one electron, whereas a 4Fe4S iron-sulfur center carries two electrons. 
C) Iron-sulfur centers generally have a higher redox potential than do cytochromes. 
D) Mitochondrial electron carriers with the highest redox potential generally contain copper ions and/or heme groups. 
A) Ubiquinone is a small, hydrophobic protein containing a metal group that acts as an electron carrier. 
B) A 2Fe2S iron-sulfur center carries one electron, whereas a 4Fe4S iron-sulfur center carries two electrons. 
C) Iron-sulfur centers generally have a higher redox potential than do cytochromes. 
D) Mitochondrial electron carriers with the highest redox potential generally contain copper ions and/or heme groups.

Question 11

What is the final result of the electron transfers in Stage 1 of the membrane-based processes that drive ATP synthesis in mitochondria?

Accepted Answer

A) OH− is oxidized to O2 
B) pyruvate is oxidized to CO2 
C) O2 is reduced to H2O 
D) H− is converted to H2 
A) OH− is oxidized to O2 
B) pyruvate is oxidized to CO2 
C) O2 is reduced to H2O 
D) H− is converted to H2

Question 12

Match between columns
                        Premises: The number and location of mitochondria within a cell can change, depending on both the cell type and the amount of energy required.

The inner mitochondrial membrane is actually a series of discrete, flattened, membrane-enclosed compartments called cristae, similar to what is seen in the Golgi apparatus.
The inner mitochondrial membrane contains porins, which allow pyruvate to enter for use in the citric acid cycle.

The intermembrane space of the mitochondria is chemically equivalent to the cytosol with respect to pH and the small molecules present.

Accepted Answer

The Answer of False and True is...

Question 13

Which of the following statements describes the mitochondrial outer membrane?

Accepted Answer

A) It is permeable to molecules with molecular mass as high as 5000 daltons. 
B) It contains transporters for ATP molecules. 
C) It contains proteins that are released during apoptosis. 
D) It contains enzymes required for the oxidation of fatty acids. 
A) It is permeable to molecules with molecular mass as high as 5000 daltons. 
B) It contains transporters for ATP molecules. 
C) It contains proteins that are released during apoptosis. 
D) It contains enzymes required for the oxidation of fatty acids.

Question 14

The ATP synthase found in chloroplasts is structurally similar to the ATP synthase in mitochondria.Given that ATP is being synthesized in the stroma, where will the F0 portion of the ATP synthase be located?

Accepted Answer

A) thylakoid space 
B) stroma 
C) inner membrane 
D) thylakoid membrane 
A) thylakoid space 
B) stroma 
C) inner membrane 
D) thylakoid membrane

Question 15

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
$\begin{array}{lll}
\text { cytochrome } b-c_{1} \text { complex } & \text { oxidation } & \text { second } \
\text { cytochrome } c & \text { oxidation-reduction } & \text { the } \
\text { cytochrome } c \text { oxidase } & \text { phosphorylation } & \text { third } \
\text { first } & \text { plastoquinone } & \text { uniquinone } \
\text { NADH dehydrogenase } & \text { reduction } &
\end{array}$

NADH dehydrogenase reduction
NADH donates electrons to the __________ of the three respiratory enzyme complexes in the mitochondrial electron-transport-chain.__________ is a small protein that acts as a mobile electron carrier in the respiratory chain.__________ transfers electrons to oxygen.Electron transfer in the chain occurs in a series of __________ reactions.The first mobile electron carrier in the respiratory chain is __________.

Accepted Answer

NADH donates electrons to the first of t

Question 16

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
$\begin{array}{lll}
\text { 3-phosphoglycerate } & \text { NADPH } & \text { starch } \
\text { ATP } & \text { pyruvate } & \text { sucrose } \
\text { glyceraldehyde 3-phosphate } & \text { ribose 1,5-bisphosphate } & \
\text { NADH } & \text { ribulose 1,5-bisphosphate } &
\end{array}$

In the carbon-fixation process in chloroplasts, carbon dioxide is initially added to the sugar __________.The final product of carbon fixation in chloroplasts is the three-carbon compound __________.This is converted into __________ (which can be used directly by the mitochondria), into __________ (which is exported to other cells), and into __________ (which is stored in the stroma).The carbon-fixation cycle requires energy in the form of __________ and reducing power in the form of __________.

Accepted Answer

In the carbon-fixation process in chloro

Question 17

Photosynthesis is a process that takes place in chloroplasts and uses light energy to generate high-energy electrons, which are passed along an electron-transport chain.Where are the proteins of the electron-transport chain located in chloroplasts?

Accepted Answer

A) thylakoid space 
B) stroma 
C) inner membrane 
D) thylakoid membrane 
A) thylakoid space 
B) stroma 
C) inner membrane 
D) thylakoid membrane

Question 18

Consider a redox reaction between molecules A and B.Molecule A has a redox potential of −100 mV and molecule B has a redox potential of +100 mV.For the transfer of electrons from A to B, is the ΔG° positive or negative or zero? Under what conditions will the reverse reaction, transfer of electrons from B to A, occur?

Accepted Answer

The ΔG° is negative.The sign of ΔG° is t

Question 19

The relationship of free-energy change (ΔG) to the concentrations of reactants and products is important because it predicts the direction of spontaneous chemical reactions.In the hydrolysis of ATP to ADP and inorganic phosphate (Pi), the standard free-energy change (ΔG°) is −7.3 kcal/mole.The free-energy change depends on concentrations according to the following equation:
ΔG = ΔG° + 1.42 log10 ([ADP] [Pi]/[ATP])
In a resting muscle, the concentrations of ATP, ADP, and Pi are approximately 0.005 M, 0.001 M, and 0.010 M, respectively.What is the ΔG for ATP hydrolysis in resting muscle?

Accepted Answer

A) −11.1 kcal/mole 
B) −8.72 kcal/mole 
C) 6.01 kcal/mole 
D) −5.88 kcal/mole 
A) −11.1 kcal/mole 
B) −8.72 kcal/mole 
C) 6.01 kcal/mole 
D) −5.88 kcal/mole

Question 20

Explain how scientists used artificial vesicles to prove that the generation of ATP by the ATP synthase was not powered by a single high-energy intermediate but rather by a proton gradient.Be sure to describe the two experiments that were negative controls (no ATP generated), the positive control (ATP generated as expected), and a fourth experiment proving that the gradient is the required energy source.

Accepted Answer

In all the experiments, artificial lipos

Which of the following components of the electron-transport chain does NOT act as a proton pump?

NADH contains a high-energy bond that, when cleaved, donates a pair of electrons to the electron-transport chain.What are the immediate products of this bond cleavage?

Compare and contrast the process of reducing N₂ to NH₃ in Methanococcus jannaschii to the reduction of O₂ to H₂0 in the mitochondrial matrix.What inferences can you draw with respect to the early evolution of energy-generating systems.

What is the source of protons that are pumped out of the mitochondrial matrix in Stage 1 of oxidative phosphorylation?

Explain how the diffusion of ubiquinone in three dimensions is restricted in order to ensure its proximity to the other enzyme complexes for the rapid transfer of electrons?

Which of the following is NOT part of the process known as "oxidative phosphorylation"?

Ubiquinone is one of two mobile electron carriers in the electron-transport chain.Where does the additional pair of electrons reside in the reduced ubiquinone molecule?

NADH and FADH₂ carry high-energy electrons that are used to power the production of ATP in the mitochondria.These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle.Which molecule below can produce the most ATP? Explain your answer.

Which of the following statements is TRUE?

What is the final result of the electron transfers in Stage 1 of the membrane-based processes that drive ATP synthesis in mitochondria?

Which of the following statements describes the mitochondrial outer membrane?

The ATP synthase found in chloroplasts is structurally similar to the ATP synthase in mitochondria.Given that ATP is being synthesized in the stroma, where will the F₀ portion of the ATP synthase be located?

Photosynthesis is a process that takes place in chloroplasts and uses light energy to generate high-energy electrons, which are passed along an electron-transport chain.Where are the proteins of the electron-transport chain located in chloroplasts?

Cells: The Fundamental Units of Life

Chemical Components of Cells

Energy, Catalysis, and Biosynthesis

Protein Structure and Function

DNA and Chromosomes

DNA Replication and Repair

From DNA to Protein

Control of Gene Expression

How Genes and Genomes Evolve

Analyzing the Structure and Function of Genes

Membrane Structure

Transport Across Cell Membranes

How Cells Obtain Energy From Food

Intracellular Compartments and Protein Transport

Cell Signaling

Cytoskeleton

The Cell-Division Cycle

Sexual Reproduction and the Power of Genetics

Cell Communities: Tissues, Stem Cells, and Cancer

Filters

Exam 14: Energy Generation in Mitochondria and Chloroplasts

Which of the following components of the electron-transport chain does NOT act as a proton pump?

NADH contains a high-energy bond that, when cleaved, donates a pair of electrons to the electron-transport chain.What are the immediate products of this bond cleavage?

Compare and contrast the process of reducing N2 to NH3 in Methanococcus jannaschii to the reduction of O2 to H20 in the mitochondrial matrix.What inferences can you draw with respect to the early evolution of energy-generating systems.

What is the source of protons that are pumped out of the mitochondrial matrix in Stage 1 of oxidative phosphorylation?

Explain how the diffusion of ubiquinone in three dimensions is restricted in order to ensure its proximity to the other enzyme complexes for the rapid transfer of electrons?

Which of the following is NOT part of the process known as "oxidative phosphorylation"?

Ubiquinone is one of two mobile electron carriers in the electron-transport chain.Where does the additional pair of electrons reside in the reduced ubiquinone molecule?

NADH and FADH2 carry high-energy electrons that are used to power the production of ATP in the mitochondria.These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle.Which molecule below can produce the most ATP? Explain your answer.

Which of the following statements is TRUE?

What is the final result of the electron transfers in Stage 1 of the membrane-based processes that drive ATP synthesis in mitochondria?

Which of the following statements describes the mitochondrial outer membrane?

The ATP synthase found in chloroplasts is structurally similar to the ATP synthase in mitochondria.Given that ATP is being synthesized in the stroma, where will the F0 portion of the ATP synthase be located?

Photosynthesis is a process that takes place in chloroplasts and uses light energy to generate high-energy electrons, which are passed along an electron-transport chain.Where are the proteins of the electron-transport chain located in chloroplasts?

Cells: The Fundamental Units of Life

Chemical Components of Cells

Energy, Catalysis, and Biosynthesis

Protein Structure and Function

DNA and Chromosomes

DNA Replication and Repair

From DNA to Protein

Control of Gene Expression

How Genes and Genomes Evolve

Analyzing the Structure and Function of Genes

Membrane Structure

Transport Across Cell Membranes

How Cells Obtain Energy From Food

Intracellular Compartments and Protein Transport

Cell Signaling

Cytoskeleton

The Cell-Division Cycle

Sexual Reproduction and the Power of Genetics

Cell Communities: Tissues, Stem Cells, and Cancer

Filters

Compare and contrast the process of reducing N₂ to NH₃ in Methanococcus jannaschii to the reduction of O₂ to H₂0 in the mitochondrial matrix.What inferences can you draw with respect to the early evolution of energy-generating systems.

NADH and FADH₂ carry high-energy electrons that are used to power the production of ATP in the mitochondria.These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle.Which molecule below can produce the most ATP? Explain your answer.

The ATP synthase found in chloroplasts is structurally similar to the ATP synthase in mitochondria.Given that ATP is being synthesized in the stroma, where will the F₀ portion of the ATP synthase be located?