Question 1

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

Accepted Answer

Cytochrome c does not act as a proton pump, but rather shuttles electrons between other components of the electron transport chain.

Question 2

Which of the following statements describes the mitochondrial matrix?

Accepted Answer

The mitochondrial matrix contains enzymes required for the oxidation of fatty acids. Choice A is incorrect because the mitochondrial matrix is not permeable to molecules with molecular mass as high as 5000 daltons. Choice B is incorrect because the transporters for ATP molecules are located in the mitochondrial inner membrane. Choice C is incorrect because proteins released during apoptosis are located in the intermembrane space of the mitochondria, not the mitochondrial matrix.

Question 3

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

Accepted Answer

Oxidative phosphorylation occurs in the mitochondria and involves the electron-transport chain and ATP synthase to generate ATP. Glucose conversion into pyruvate occurs during glycolysis in the cytosol, which is not part of oxidative phosphorylation.

Question 4

Electron transport is coupled to ATP synthesis in mitochondria, in chloroplasts, and in the thermophilic bacterium Methanococcus.Which of the following is likely to affect the coupling of electron transport to ATP synthesis in ALL of these systems?

Accepted Answer

An ADP analog that inhibits ATP synthase would affect the coupling of electron transport to ATP synthesis in all three systems, as ATP synthase is the enzyme responsible for synthesizing ATP during oxidative phosphorylation. In contrast, the potent inhibitor of cytochrome c oxidase would only affect electron transport in mitochondria and chloroplasts, while the removal of oxygen would only affect electron transport in mitochondria. The absence of light would only affect electron transport in chloroplasts.

Question 5

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

When NADH donates electrons, it is oxidized to NAD⁺ and releases a hydride ion (H⁻), which consists of a proton and two electrons.

Question 6

During Stage 2 of oxidative phosphorylation, ATP synthesis is powered by movement of __________ ions through the __________.

Accepted Answer

During Stage 2 of oxidative phosphorylation, ATP synthesis is powered by movement of hydrogen ions (H+) through the ATP synthase complex. This movement creates a proton gradient that drives the synthesis of ATP. Choice A and B are not correct because they do not accurately describe the process of oxidative phosphorylation. Choice D is partially correct as electrons play a role in the electron-transport chain, but it is not the direct power source for ATP synthesis in Stage 2.

Question 7

Osmosis describes the movement of water across a biological membrane and down its concentration gradient.In chemiosmosis, useful energy is harnessed by the cell from the movement of __________ across the inner mitochondrial membrane into the matrix __________ a concentration gradient.

Accepted Answer

Chemiosmosis involves the movement of protons (H+) across the inner mitochondrial membrane into the matrix down a concentration gradient, which is then used to generate ATP through the action of ATP synthase. None of the other options accurately describe this process.

Question 8

Which of the following statements about mitochondrial division is TRUE?

Accepted Answer

Mitochondrial division is mechanistically similar to prokaryotic cell division because mitochondria are believed to have originated from engulfed prokaryotic cells that evolved into symbiotic organelles. The process of mitochondrial division involves the formation of a constriction ring, similar to the one formed during prokaryotic cell division, that eventually leads to the separation of the two daughter mitochondria. A and B are incorrect statements because mitochondria can divide at different rates in different cell types and do not necessarily divide synchronously with the cell cycle. D is an incorrect statement because mitochondria can produce energy while undergoing division.

Question 9

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

The final result of the electron transfers in Stage 1 of the membrane-based processes that drive ATP synthesis in mitochondria is that the electron carrier O₂ is reduced to H₂O. This reduction reaction is coupled with the pumping of protons across the inner mitochondrial membrane from the matrix to the intermembrane space, creating an electrochemical gradient that will be used to drive ATP synthesis.

Question 10

Which of the following statements describes the mitochondrial intermembrane space?

Accepted Answer

The mitochondrial intermembrane space contains proteins that are released during apoptosis, such as cytochrome c. It is not permeable to molecules with molecular mass as high as 5000 daltons, does not contain transporters for ATP molecules, and does not contain enzymes required for the oxidation of fatty acids.

Question 11

Which of the following statements is TRUE?

Accepted Answer

The pH in the mitochondrial matrix is higher (more basic) than in the intermembrane space because protons are pumped from the matrix into the intermembrane space, creating a proton gradient used for ATP synthesis. This gradient makes the matrix less acidic (higher pH) compared to the intermembrane space.

Question 12

Which of the following statements describes the phosphorylation event that occurs during the process known as "oxidative phosphorylation"?

Accepted Answer

During oxidative phosphorylation, a phosphate group is added to ADP to form ATP. This process occurs in the inner mitochondrial membrane and is driven by the electron transport chain, which generates a proton gradient that powers the ATP synthase enzyme to add the phosphate group to ADP to form ATP.

Question 13

Which of the following statements describes the mitochondrial outer membrane?

Accepted Answer

The mitochondrial outer membrane is permeable to small molecules and ions, including those with molecular masses up to about 5000 daltons, due to the presence of porin proteins.

Question 14

The mitochondrial ATP synthase consists of several different protein subunits.Which subunit binds to ADP + P_i and catalyzes the synthesis of ATP as a result of a conformational change?

Accepted Answer

The F₁ subunit in the ATPase head is responsible for binding to ADP + P_i and catalyzing the synthesis of ATP through a conformational change. The other subunits listed (transmembrane H⁺ carrier, peripheral stalk, and central stalk) play important roles in the function of the ATP synthase, but they do not directly bind to ADP and catalyze the synthesis of ATP.

Question 15

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

Accepted Answer

The answer of What is the source of protons that...

Question 16

Which component of the electron-transport chain is required to combine the pair of electrons with molecular oxygen?

Accepted Answer

Cytochrome c oxidase is the component of the electron-transport chain that combines the pair of electrons with molecular oxygen to form water.

Question 17

Bongkrekic acid is an antibiotic that inhibits the ATP/ADP transport protein in the inner mitochondrial membrane.Which of the following will allow electron transport to occur in mitochondria treated with bongkrekic acid?

Accepted Answer

Making the inner membrane permeable to protons will allow for electron transport to occur in mitochondria treated with bongkrekic acid since it will create a proton gradient, which is necessary for ATP synthesis. The other choices are not relevant to overcoming the inhibition of the ATP/ADP transport protein.

Question 18

The overall relationship that links bond-forming reactions to membrane transport processes in the mitochondria is called

Accepted Answer

Chemiosmotic coupling refers to the process by which the energy released from bond-forming reactions (specifically, the transfer of electrons along the electron transport chain) is coupled to the generation of a proton gradient across the inner mitochondrial membrane. This proton gradient is then used to drive ATP synthesis by the enzyme ATP synthase. Therefore, chemiosmotic coupling is the overall relationship that links bond-forming reactions to membrane transport processes in the mitochondria.

Question 19

Which of the following statements describes the mitochondrial inner membrane?

Accepted Answer

The mitochondrial inner membrane contains transporters for ATP molecules, such as the ATP/ADP translocase, which facilitates the exchange of ATP and ADP across the membrane.

Question 20

Modern eukaryotes depend on mitochondria to generate most of the cell's ATP.How many molecules of ATP can a single molecule of glucose generate?

Accepted Answer

A single molecule of glucose can generate approximately 30 molecules of ATP through cellular respiration, which includes glycolysis, the citric acid cycle, and oxidative phosphorylation in the mitochondria.

Quiz 14: Energy Generation in Mitochondria and Chloroplasts

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

Which of the following statements describes the mitochondrial matrix?

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

Electron transport is coupled to ATP synthesis in mitochondria, in chloroplasts, and in the thermophilic bacterium Methanococcus.Which of the following is likely to affect the coupling of electron transport to ATP synthesis in ALL of these systems?

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?

During Stage 2 of oxidative phosphorylation, ATP synthesis is powered by movement of ions through the .

Osmosis describes the movement of water across a biological membrane and down its concentration gradient.In chemiosmosis, useful energy is harnessed by the cell from the movement of across the inner mitochondrial membrane into the matrix a concentration gradient.

Which of the following statements about mitochondrial division 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 intermembrane space?

Which of the following statements is TRUE?

Which of the following statements describes the phosphorylation event that occurs during the process known as "oxidative phosphorylation"?

Which of the following statements describes the mitochondrial outer membrane?

The mitochondrial ATP synthase consists of several different protein subunits.Which subunit binds to ADP + P_i and catalyzes the synthesis of ATP as a result of a conformational change?

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

Which component of the electron-transport chain is required to combine the pair of electrons with molecular oxygen?

Bongkrekic acid is an antibiotic that inhibits the ATP/ADP transport protein in the inner mitochondrial membrane.Which of the following will allow electron transport to occur in mitochondria treated with bongkrekic acid?

The overall relationship that links bond-forming reactions to membrane transport processes in the mitochondria is called

Which of the following statements describes the mitochondrial inner membrane?

Modern eukaryotes depend on mitochondria to generate most of the cell's ATP.How many molecules of ATP can a single molecule of glucose generate?

Quiz 14: Energy Generation in Mitochondria and Chloroplasts

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

Which of the following statements describes the mitochondrial matrix?

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

Electron transport is coupled to ATP synthesis in mitochondria, in chloroplasts, and in the thermophilic bacterium Methanococcus.Which of the following is likely to affect the coupling of electron transport to ATP synthesis in ALL of these systems?

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?

During Stage 2 of oxidative phosphorylation, ATP synthesis is powered by movement of __________ ions through the __________.

Osmosis describes the movement of water across a biological membrane and down its concentration gradient.In chemiosmosis, useful energy is harnessed by the cell from the movement of __________ across the inner mitochondrial membrane into the matrix __________ a concentration gradient.

Which of the following statements about mitochondrial division 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 intermembrane space?

Which of the following statements is TRUE?

Which of the following statements describes the phosphorylation event that occurs during the process known as "oxidative phosphorylation"?

Which of the following statements describes the mitochondrial outer membrane?

The mitochondrial ATP synthase consists of several different protein subunits.Which subunit binds to ADP + Pi and catalyzes the synthesis of ATP as a result of a conformational change?

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

Which component of the electron-transport chain is required to combine the pair of electrons with molecular oxygen?

Bongkrekic acid is an antibiotic that inhibits the ATP/ADP transport protein in the inner mitochondrial membrane.Which of the following will allow electron transport to occur in mitochondria treated with bongkrekic acid?

The overall relationship that links bond-forming reactions to membrane transport processes in the mitochondria is called

Which of the following statements describes the mitochondrial inner membrane?

Modern eukaryotes depend on mitochondria to generate most of the cell's ATP.How many molecules of ATP can a single molecule of glucose generate?

During Stage 2 of oxidative phosphorylation, ATP synthesis is powered by movement of ions through the .

Osmosis describes the movement of water across a biological membrane and down its concentration gradient.In chemiosmosis, useful energy is harnessed by the cell from the movement of across the inner mitochondrial membrane into the matrix a concentration gradient.

The mitochondrial ATP synthase consists of several different protein subunits.Which subunit binds to ADP + P_i and catalyzes the synthesis of ATP as a result of a conformational change?