Biology 302 Chapter 14

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? (a) transmembrane H+ carrier (b) F1 ATPase head (c) peripheral stalk (d) central stalk

(b) F1 ATPase head

Which of the following statements about electron transport in mitochondria is false? (a) Initial electron is provided from NADH made by glycolysis .(b) Ubiquinone and cytochrome c are used as electron carrier. (c) Oxygen is consumed at first step in electron transfer. (d) Electron carrier molecules can carry hydrogen ion (proton) when they receive electron.

(c) Oxygen is consumed at first step in electron transfer.

Which of the following components of electron-transport chain act as a proton pump in the mitochondria? (a) NADH dehydrogenase (b) cytochrome c oxidase (c) cytochrome c reductase (d) all of above

(d) all of above

In mitochondria, with the complete breakdown of glucose, about how many molecules of ATP can be produced for each molecule of glucose oxidized? A. 2 B. 12 C. 30 D. 50

30

Which of the following drives the production of ATP from ADP and Pi by ATP synthase? A. A proton gradient B. A Na+ gradient C. Phosphorylation

A proton gradient

Pyruvate is oxidized to form CO2 and acetyl CoA bythe pyruvate dehydrogenase complex. How manydifferent enzymatic activities are required andwhere is it located? A. 3; in the mitochondria matrix B. 3; in the mitochondria intermembrane space C. 3; in the cytoplasm D. 1; in the cytoplasm

A. 3; in the mitochondria matrix

What is the main chemical energy currency in cells? A. Glucose B. NADH C. ATP D. High-energy electrons

ATP

What occurs when ATP synthase pumps H+ across a membrane against the electrochemical proton gradient? A. ATP synthase transports Na+ in the opposite direction across the membrane B. ATP synthase cleaves ATP to form ADP and Pi C. ATP synthase catalyzes the formation of ATP from ADP and Pi

ATP synthase cleaves ATP to form ADP and Pi

Energy efficiency is bases on the amount of energy produced per unit available. About how much more efficient is aerobic respiration compared to anaerobic respiration? A. 3 times B. 15 times C. 50 times D. 150 times

B. 15 times

The mitochondrial ATP synthase consists of several different protein subunits. Which subunit catalyzes the synthesis of ATP as a result of a conformational change? A. transmembrane H+carrier B. F1 ATPase head C. peripheral stalk D. central stalk

B. F1 ATPase head

Which of the following statements describes the mitochondrial inner membrane? A. It is permeable to molecules with molecular mass as high as 5000 daltons. B. It contains transporters for ATP molecules C. It contains enzymes required for the oxidation of fatty acids. D. It contains proteins that are released during apoptosis.

B. It contains transporters for ATP molecules.

Which of the following organisms do not have mitochondria in their cells? A. Plants B. Animals C. Bacteria D. Eukaryotic microorganisms

Bacteria

In the final stage of the oxidation of food molecules,a gradient of protons is formed across the inner mitochondrial membrane, which is normally impermeable to protons. If cells were exposed to an agent that causes the membrane to become freely permeable to protons, which of the following effects would you expect to observe? A. The consumption of oxygen would fall. B. Carbon dioxide production would cease. C. The ratio of ATP to ADP in the cytoplasm would fall. D. NADH would build up.

C. The ratio of ATP to ADP in the cytoplasm would fall.

Which of the following steps or processes in aerobicrespiration include the production of carbondioxide? A. breakdown of glycogen B. glycolysis C. conversion of pyruvate to acetyl CoA D. oxidative phosphorylation

C. conversion of pyruvate to acetyl CoA

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. (Hint: try thinking of the analogy) A. ATP, against B. electrons, down C. protons, down D. ADP, against

C. protons, down

As one oxaloacetate molecule reacts with acetylCoAand eventually regenerated, what is produced? A. 3 CO2, 2 NADH, 1 FADH2, and 1 ATP B. 2 CO2, 4 NADH, and 1 ATP C. 2 CO2, 4 NADH, and 1 GTP D. 2 CO2, 3 NADH, 1 FADH2, and 1 GTP

D. 2 CO2, 3 NADH, 1 FADH2, and 1 GTP

Which of the following statements describes thephosphorylation event that occurs during oxidativephosphorylation? A. ATP is hydrolyzed in order to add phosphategroups to protein substrates. B. A phosphate group is added to molecularoxygen. C. Inorganic phosphate is transported into themitochondrial matrix, increasing the localphosphate concentration. D. A phosphate group is added to ADP.

D. A phosphate group is added to ADP.

Which of the following statements is true about the electron transport chain? A. Electrons start out at very high energy and lose energy at each transfer step. B. Electrons start out at very low energy and gain energy at each transfer step. C. Electrons gain and release energy as they move from one complex to another in the electron transport chain.

Electrons start out at very high energy and lose energy at each transfer step.

Why does a single molecule of NADH result in the production of more ATP molecules than a single molecule of FADH2 via oxidative phosphorylation? A. NADH donates more electrons to the chain. B. FADH2 feeds its electrons into the electron transport chain further along the chain. C. FADH2 is less likely than NADH to participate in the electron transport chain.

FADH2 feeds its electrons into the electron transport chain further along the chain

It is energetically favorable for protons to flow in which direction? A. From the intermembrane space to the mitochondrial matrix B. From the mitochondrial matrix to the intermembrane space

From the intermembrane space to the mitochondrial matrix

Which of the following is not a direct source of fuel for mitochondria? A. Glucose B. Pyruvate C. Fatty acids

Glucose

In the electron transport chain, what provides the main reservoir for protons that are pumped across the membrane? A. NADH B. H2O C. Glucose

H2O

What is the ratio of ATP and ADP concentrations in the cytosol of a cell? A. High ATP/ADP ratio B. High ADP/ATP ratio

High ATP/ADP ratio

In a eukaryotic cell, where are most of the proteins for the electron transport chain located? A. In the plasma membrane B. In the mitochondrial inner membrane C. In the mitochondrial outer membrane D. In the ER membrane

In the mitochondrial inner membrane

chemiosmotic coupling

Mechanism that uses the energy stored in a transmembrane proton gradient to drive an energy-requiring process, such as the synthesis of ATP or the transport of a molecule across a membrane.

ATP synthase

Membrane-associated enzyme complex that catalyzes the formation of ATP from ADP and inorganic phosphate during oxidative phosphorylation and photosynthesis

In mitochondria, what is the final electron acceptor in the electron transport chain? A. Carbon dioxide (CO2) B. Molecular oxygen (O2) C. Water (H2O) D. NADH and FADH2

Molecular oxygen (O2)

The electron transport chain accepts high-energy electrons from: A. ATP. B. pyruvate. C. NADH and FADH2. D. acetyl CoA.

NADH and FADH2

Which of the following is true? A. NADH has a strong affinity for electrons and a positive redox potential. B. NADH has a weak affinity for electrons and a negative redox potential. C. NADH has a strong affinity for electrons and a negative redox potential. D. NADH has a weak affinity for electrons and a negative redox potential.

NADH has a weak affinity for electrons and a negative redox potential.

Which of the following processes involves a membrane? A. Substrate level phosphorylation B. Oxidative phosphorylation

Oxidative phosphorylation

Which of the following is NOT true of mitochondria? A. They are similar in size and shape to bacteria. B. They contain their own DNA and RNA. C. They contain an outer membrane, and inner membrane, and two internal compartments. D. They are replaced by chloroplasts in plants. E. Inside a cell, they are mobile, constantly changing shape and position.

They are replaced by chloroplasts in plants.

Mitochondria can change their location, shape, and number in the cell to suit the needs of a cell. A. True B. False

True

The outer membrane of a mitochondrion is permeable to all small molecules, including small proteins. A. True B. False

True

The proton gradient can drive the active transport of metabolites into and out of the mitochondrion. A. True B. False

True

Ubiquinone has a redox potential of +30 mV, while cytochrome c has a redox potential of +230 mV. In the electron transport chain, electrons flow from: A. Ubiquinone to cytochrome c. B. Cytochrome c to ubiquinone.

Ubiquinone to cytochrome c.

Which of the following statements is NOT true of electron transfer in the electron transport chain? A. Each electron transfer is an oxidation-reduction reaction. B. When an electron carrier accepts an electron, it becomes oxidized. C. NADH has a relatively low electron affinity.

When an electron carrier accepts an electron, it becomes oxidized.

As electrons move through the electron transport chain, they are passed from: A. a carrier molecule of lower electron affinity to a carrier molecule of higher electron affinity. B. a carrier molecule of higher electron affinity to a carrier molecule of lower electron affinity. check my answer

a carrier molecule of lower electron affinity to a carrier molecule of higher electron affinity.

ATP synthase: A. can produce ATP but cannot break it down. B. can break down ATP but cannot produce it. C. can either produce or break down ATP depending on the magnitude of the electrochemical proton gradient.

can either produce or break down ATP depending on the magnitude of the electrochemical proton gradient.

Membrane-bound, colored, heme-containing protein that transfers electrons during cellular respiration.

cytochrome

Protein complex that serves as the final electron carrier in the respiratory chain; removes electrons from cytochrome c and passes them to O2 to produce H2O.

cytochrome c oxidase

NADH has a strong tendency to: A. accept electrons. B. donate electrons. C. either donate or accept electrons depending on the electrochemical proton gradient.

donate electrons

The organelles that produce ATP in eukaryotic cells: A. reproduce sexually. B. harbor eukaryotic-like biosynthetic machinery for making RNA. C. have a separate set of DNA that contains many of the same genes found in the nucleus. D. evolved from bacteria engulfed by ancestral cells billions of years ago.

evolved from bacteria engulfed by ancestral cells billions of years ago.

The electron transport chain pumps protons: A. from the intermembrane space to the matrix. B. from the matrix to the intermembrane space. C. from the matrix to the cytosol.

from the matrix to the intermembrane space.

When the difference in redox potential between two pairs of molecules is highly positive, then the transfer of the electrons is: A. highly unfavorable. B. highly favorable. C. highly inefficient. D. prohibited by the laws of thermodynamics.

highly favorable.

Metal complex found in electron carriers that operate early in the electron-transport chain; has a relatively weak affinity for electrons.

iron-sulfur center

Cellular respiration: A. is more efficient at generating energy than a gasoline-powered engine. B. is less efficient at generating energy than a gasoline engine C. operates at about the same efficiency as a gasoline-powered engine D. cannot be compared to the efficiency of a gasoline engine.

is more efficient at generating energy than a gasoline-powered engine.

Large internal compartment within a mitochondrion.

matrix

When protons move down their electrochemical gradient into the mitochondrial matrix, they: A. produce NADH. B. produce ATP. C. consume ATP. D. they move electrons through the respiratory chain.

produce ATP.

In the electron transport chain, as electrons move along a series of carriers, they release energy that is used to: A. pump protons across a membrane. B. phosphorylate ADP to form ATP. C. split water into protons and oxygen.

pump protons across a membrane.

The movement of electrons through the electron transport chain: A. consumes ATP. B. produces NADH. C. pumps protons across the inner mitochondrial membrane. D. pumps ATP across the inner mitochondrial membrane.

pumps protons across the inner mitochondrial membrane.

Small, lipid-soluble, mobile electron carrier molecule found in the respiratory and photosynthetic electron-transport chains.

quinone

Two molecules that can be interconverted by the gain or loss of an electron; for example, NADH and NAD+.

redox pair

A measure of the tendency of a given redox pair to donate or accept electrons.

redox potential

A reaction in which electrons are transferred from one chemical species to another. An oxidation-reduction reaction.

redox reaction

When O2 accepts electrons in the electron transport chain, O2 becomes _______. A. oxidized B. reduced

reduced

Set of proteins in the inner mitochondrial membrane that facilitates the transfer of high-energy electrons from NADH to water while pumping protons into the intermembrane space.

respiratory enzyme complex

The citric acid cycle is a series of oxidation reactionsthat removes carbon atoms from substrates in theform of CO2. Where do the oxygen atoms in thecarbon dioxide molecules come from? A. phosphates B. water C. molecular oxygen D. acetyl CoA

water