Chapter 7

The terminal electron acceptor of a mitochondrial electron transport chain is: NADPH. water. oxygen. NADP+. NAD+.

oxygen.

Which process produces the highest number of reduced electron carriers and thus the greatest potential for generating ATP? pyruvate oxidation the citric acid cycle Each stage contributes equally. glycolysis

the citric acid cycle

In eukaryotic cells, glycolysis occurs in: the endoplasmic reticulum. the nucleus. the cytoplasm. vacuoles. the matrix of the mitochondria.

the cytoplasm.

The energy required to drive the synthesis of the majority of the ATP generated during aerobic respiration comes most directly from: the flow of protons through an ATP synthase complex. sunlight. the conversion of glucose into two molecules of pyruvate. the movement of electrons through an electron transport chain. removal of a phosphate group from another molecule.

the flow of protons through an ATP synthase complex.

Which molecule(s) serve as electron donors for the mitochondrial electron transport chain? (Select all that apply.) NADH FADH2 ATP NADPH O2

NADH FADH2

The immediate source of electrons for the electron transport chain is: NADH and FADH2. H2O. pyruvate. O2. NAD+.

NADH and FADH2.

Which statement about the citric acid cycle in the context of cellular respiration is true? The citric acid cycle provides the oxygen that is needed for cellular respiration. There is no role for the citric acid cycle in cellular respiration. ATP is produced from the citric acid cycle and this is what drives cellular respiration. The citric acid cycle produces electron donors NADH and FADH2 which serve as an electron source for the electron transport chain.

The citric acid cycle produces electron donors NADH and FADH2 which serve as an electron source for the electron transport chain.

Energy released by transferring electrons along the electron transport chain is stored as potential energy in the form of: redox couples. ATP. ATP synthase. coenzyme Q. a proton gradient.

a proton gradient.

In cellular respiration, oxygen: gains electrons and is reduced. loses electrons and is oxidized. gains electrons and is oxidized. loses electrons and is reduced. None of the other answer options is correct.

gains electrons and is reduced.

The first stage in the production of ATP via the oxidation of glucose molecules is referred to as: the citric acid cycle. glycolysis. the Calvin cycle. the electron transport chain. photosynthesis.

glycolysis.

The breakdown of fatty acids takes place by a process called: beta‐oxidation. oxidative phosphorylation. pyruvate oxidation. glycolysis. electron transport.

beta‐oxidation.

An electron from NADH entering the electron transport chain would travel among components of the chain in what sequence? complex I, coenzyme Q, complex III, cytochrome c, complex IV, oxygen complex I, coenzyme Q, complex III, cytochrome c, ATP synthase, oxygen complex I, coenzyme Q, complex II, cytochrome c, complex III, coenzyme Q, complex IV, cytochrome c, oxygen complex II, cytochrome c, complex IV, cytochrome c, oxygen complex II, coenzyme Q, complex IV, cytochrome c, ATP synthase, oxygen

complex I, coenzyme Q, complex III, cytochrome c, complex IV, oxygen

Select the arrow(s) that represent the direction(s) in which: protons are pumped when coupled to electron transfer protons flow through ATP synthase to power ATP synthesis 1 - A; 2 - A 1 - B; 2 - A 1 - A; 2 - B 1 - B; 2 - B

1 - A; 2 - B

Which form of energy is produced at 1 and 2 in the figure? 1: chemical energy; 2: chemical energy 1: chemical energy; 2: potential energy 1: potential energy; 2: chemical energy 1: potential energy; 2: kinetic energy 1: kinetic energy; 2: chemical energy 1: kinetic energy; 2: potential energy

1: potential energy; 2: chemical energy

In which order does one molecule of glucose undergoing cellular respiration go through processes 1-4? 1. glycolysis 2. oxidative phosphorylation 3. pyruvate oxidation 4. citric acid cycle 1>3>2>4 1>3>4>2 1>2>3>4 1>4>3>2 1>4>2>3

1>3>4>2

Nicotinamide Adenine Dinucleotide is an electron carrier in many important cellular reactions. It exists in an oxidized form (NAD+) and a reduced form (NADH). What is the missing component in the reaction: NAD+ + ____ + H+ → NADH? 4e- O2 2e- heat H2O

2e-

In which compartment does pyruvate oxidation takes place? B C A

A

Which best describes energy captured in ATP during aerobic cellular respiration? It depends on the organism. Some produce most of their ATP by substrate‐level phosphorylation, and some produce most of their ATP by oxidative phosphorylation. A small amount of energy is captured in ATP by substrate‐level phosphorylation; most is captured in ATP by oxidative phosphorylation. An equal amount is captured in ATP by oxidative phosphorylation and substrate‐level phosphorylation. None of the other answer options is correct. A small amount of energy is captured in ATP by oxidative phosphorylation; most is captured in ATP by substrate‐level phosphorylation.

A small amount of energy is captured in ATP by substrate‐level phosphorylation; most is captured in ATP by oxidative phosphorylation.

During a long bout of sustained exercise, in which order will your body's energy stores/sources be used? fatty acids, glycogen stored in the liver, glycogen stored in the muscle, ATP stored in the muscle glycogen stored in muscle, ATP stored in the muscle, glycogen stored in the liver, fatty acids ATP stored in muscle, glycogen stored in muscle, glycogen stored in the liver, fatty acids ATP stored in muscle, fatty acids, glycogen stored in the muscle, glycogen stored in the liver ATP stored in muscle, glycogen stored in the liver, glycogen stored in the muscle, fatty acids

ATP stored in muscle, glycogen stored in muscle, glycogen stored in the liver, fatty acids

Why is pyruvate imported from the cytoplasm into the mitochondrial matrix? Although pyruvate is made in the cytoplasm, the product of its oxidation, acetyl‑CoA, is a substrate for the citric acid cycle, which is located in the mitochondrial matrix. Mitochondria use pyruvate as an electron donor for the electron transport chain. Pyruvate is the starting substrate for the citric acid cycle, which takes place in the mitochondrial matrix. Pyruvate is a toxic byproduct of glycolysis, and the cell removes this compound by importing it into mitochondria, where it can be degraded into non‑toxic acetyl‑CoA.

Although pyruvate is made in the cytoplasm, the product of its oxidation, acetyl‑CoA, is a substrate for the citric acid cycle, which is located in the mitochondrial matrix.

Where are protein complexes I through IV of the electron transport chain located? A C D B

C

Which of these reactions summarizes the overall reactions of cellular respiration? C6H12O6 + 6 O2 + energy → 6 CO2 + 12 H2O 6 CO2 + 6 H2O + energy → C6H12O6 + 6 O2 H2O → 2 H+ + 1/2 O2 + 2e- 6 CO2 + 6 O2 → C6H12O6 + 6 H2O C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy

The reaction of iron with oxygen to form iron oxide is an example of an oxidation-reduction reaction: 4Fe + 3O2 → 2Fe2O3. In this reaction ______ loses electrons and is ______. Fe2O3; reduced O2; oxidized O2; reduced Fe; reduced Fe; oxidized

Fe; oxidized

What happens when glucose is phosphorylated during phase 1 of glycolysis? It provides electrons to reduce NADH in phase 3. Phosphorylated glucose enters the mitochondrion. Glucose is destabilized so that it can be broken apart in phase 2. It provides electrons to reduce FADH in phase 3. ATP is produced.

Glucose is destabilized so that it can be broken apart in phase 2.

Which statement is one explanation for why glycolysis is believed to have arisen very early in the evolution of life? It does not require oxygen. It produces no CO2. It splits glucose into two 3-carbon compounds. It requires a source of NAD+. It produces only a small amount of ATP.

It does not require oxygen.

Which statement best describes how ATP synthase converts the potential energy of the proton gradient to the chemical energy of ATP? Kinetic energy from the flow of protons through the F0 subunit oxidizes the F1 subunit, which allows ADP to be reduced to ATP. Kinetic energy from the flow of protons is converted to the kinetic energy of rotation of the F0 subunit; the rotation of the F0 subunit leads to rotation of the F1 subunit, which can then catalyze ATP synthesis. Kinetic energy from the flow of protons through the F0 subunit reduces the F1 subunit, which allows ADP to be oxidized to ATP. Kinetic energy from the flow of protons is stored in a new electrochemical gradient within the F0 subunit. The potential energy of the electrochemical gradient, in turn, is converted to kinetic energy in the F1 subunit and used to catalyze ATP synthesis.

Kinetic energy from the flow of protons is converted to the kinetic energy of rotation of the F0 subunit; the rotation of the F0 subunit leads to rotation of the F1 subunit, which can then catalyze ATP synthesis.

Which molecule is the final electron acceptor for the mitochondrial electron transport chain? O2 NADH NADPH ATP FADH2

O2

The reaction of iron with oxygen to form iron oxide is an example of an oxidation‐reduction reaction: 4Fe + 3O2 → 2Fe2O3. In this reaction ______ gains electrons and is _________. Fe; reduced O2; reduced Fe2O3, reduced O2; oxidized Fe; oxidized

O2; reduced

Select the correct label for compound A. pyruvate acetyl‑CoA ATP glucose

acetyl‑CoA

Glycolysis is: aerobic in some organisms but anaerobic in others. None of the other answer options is correct. anaerobic. aerobic. aerobic in some tissues but anaerobic in others.

anaerobic.

During glycolysis, pyruvate oxidation, and the citric acid cycle, the chemical energy in glucose is transferred to: proton pumps and ATP. electron carriers and ATP. only coenzyme Q. cytochrome b and coenzyme Q. ATP and cytochrome b.

electron carriers and ATP

The majority of the energy captured in the citric acid cycle is in the form of: electrons donated to NAD+ and FAD. GTP produced by oxidative phosphorylation. ATP produced by substrate‐level phosphorylation. GTP produced by substrate‐level phosphorylation. ATP produced by oxidative phosphorylation.

electrons donated to NAD+ and FAD.

The first phase of glycolysis requires the input of two ATP molecules. It is therefore: exergonic. oxidative. endergonic. reducing.

endergonic.

Protons in a mitochondrion flow through an ATP synthase from the: cytoplasm to the intermembrane space. intermembrane space to the matrix. matrix to the intermembrane space. intermembrane space to the cytoplasm.

intermembrane space to the matrix

Due to the pumping action of the electron transport chain, protons have a high concentration in the _____ and a low concentration in the _____. mitochondrial matrix; extracellular fluid intermembrane space; mitochondrial matrix mitochondrial matrix; cytoplasm mitochondrial matrix; intermembrane space

intermembrane space; mitochondrial matrix

On completion of either ethanol or lactic acid fermentation the yield is only two ATP molecules per glucose molecule. The remaining chemical energy from the glucose is found primarily in: NADH. CO2. lactic acid and ethanol. pyruvate. FADH2.

lactic acid and ethanol.

The reaction of iron with oxygen to form iron oxide is an example of an oxidation‐reduction reaction: 4Fe + 3O2 → 2Fe2O3. In this reaction each iron atom will: gain an oxygen. lose 1½ electrons. gain 1½ electrons. lose 3 electrons. gain 3 electrons.

lose 3 electrons.

The chemical bonds of carbohydrates and lipids have high potential energy because: they are strong oxidizing agents. they are strong reducing agents. they are easy to phosphorylate. many of these bonds are C-O bonds, in which electrons are not shared equally between atoms. many of these bonds are C-C and C-H bonds, in which electrons are shared equally between atoms.

many of these bonds are C-C and C-H bonds, in which electrons are shared equally between atoms.

The citric acid cycle takes place in the: mitochondrial matrix. inner mitochondrial membrane. outer mitochondrial membrane. intermembrane space of mitochondria. cytoplasm.

mitochondrial matrix.

The oxidation of pyruvate occurs in the: lumen of the thylakoid. stroma. cytoplasm. mitochondrial intermembrane space. mitochondrial matrix.

mitochondrial matrix.

In what organelle is pyruvate oxidation carried out in a cell? chloroplast Golgi apparatus endoplasmic reticulum nucleus mitochondrion

mitochondrion

Identify organelle A and the processes that take place there. mitochondrion: glycolysis chloroplast: citric acid cycle, oxidative phosphorylation chloroplast: glycolysis mitochondrion: photosynthesis, Calvin cycle chloroplast: photosynthesis, Calvin cycle mitochondrion: citric acid cycle, oxidative phosphorylation

mitochondrion: citric acid cycle, oxidative phosphorylation

During the citric acid cycle, the production of CO2 is the result of the _____ of intermediate compounds of the citric acid cycle coupled to the production of _____. oxidation; ATP oxidation; GTP oxidation; NADH reduction; ATP reduction; NADH

oxidation; NADH

The mitochondrial electron transport chain is part of: pyruvate oxidation. fermentation. oxidative phosphorylation. glycolysis. the citric acid cycle.

oxidative phosphorylation.

Which molecule is the end product of glycolysis? pyruvate water glucose ATP

pyruvate

Which stages of cellular respiration produce CO2 as a waste product? glycolysis, pyruvate oxidation, and the citric acid cycle pyruvate oxidation and the citric acid cycle All four stages produce CO2. glycolysis and pyruvate oxidation citric acid cycle and oxidative phosphorylation

pyruvate oxidation and the citric acid cycle

In pyruvate oxidation, the electron donor is _____ and the electron acceptor is _____. acetyl-CoA; NADH pyruvate; NAD+ NAD+; NADH NADH; acetyl-CoA NAD+; pyruvate

pyruvate; NAD+

Consider the reactions. A: 4Fe + 3O2 ---> 2Fe2O3 B: 4Fe ---> 2Fe2 (3+) + 12e (-) C: 3O2 + 12e (-) ---> 2O3 (2-) The reactions shown present the overall oxidation‐reduction reaction in which elemental iron and molecular oxygen react to form iron oxide (A), and also the half-reactions showing the oxidation part and the reduction part (B & C). Compare this reaction and its half-reactions to the reaction of Nicotinamide Adenine Dinucleotide as an electron carrier in many important cellular reactions: NAD+ + 2e⁻ + H+ → NADH. Which reaction or half-reaction is most similar to this NAD+/NADH reaction? reaction C reaction A reaction B it combines both reaction B and reaction C

reaction C

During lactic acid fermentation, pyruvate is: hydrogenated. carboxylated. phosphorylated. reduced. oxidized.

reduced.

In the absence of oxygen, fermentation: regenerates NAD+ from the oxidation of pyruvate. regenerates NADH from the reduction of pyruvate regenerates NAD+ from the reduction of pyruvate. generates ATP from the reduction of pyruvate. generates ATP from the oxidation of pyruvate.

regenerates NAD+ from the reduction of pyruvate.

Glucose is stored in plants as _____ and in animals as _____ . glycogen; starch starch; glycogen cellulose; glycogen starch; cellulose cellulose; starch

starch; glycogen

What is a product (as opposed to a substrate) of at least one of the processes of cellular respiration? glucose water oxygen

water