Deck 10: Chemotrophic Energy Metabolism: Aerobic Respiration

Question 1

In prokaryotes that carry out aerobic respiration,the ________ serves the same purpose as the inner mitochondrial membrane and the ________ serves the same purpose as the mitochondrial matrix.

A)ribosomes; plasma membrane
B)cytoplasm; plasma membrane
C)cytoplasm; cell wall
D)cytoplasm; nucleoid
E)plasma membrane; cytoplasm

Answer 1

E

Question 2

When fats are used as an energy source,the glycerol portion enters ________ when it has been converted to ________.

A)the citric acid cycle; pyruvate
B)glycolysis; fructose-6-phosphate
C)the citric acid cycle; acetyl CoA
D)the electron transport system; coenzyme Q
E)glycolysis; dihydroxyacetone phosphate

Answer 2

E

Question 3

Which of the following is not one of the major transport systems of the inner mitochondrial membrane?

A)porin channel
B)dicarboxylate carrier
C)tricarboxylate carrier
D)pyruvate carrier
E)ATP-ADP carrier

Answer 3

A

Question 4

Each of the following is a step in the degradation of fatty acids except

A)hydration.
B)activation.
C)thiolysis.
D)acylation.
E)oxidation.

Question 5

The sequential process of fatty acid catabolism to acetyl CoA is called

A)the citric acid cycle.
B)the oxidative phosphorylation pathway.
C)the β-oxidation pathway.
D)the glyoxylate cycle.
E)the Cori cycle.

Question 6

In eukaryotes,pyruvate is converted to acetyl CoA

A)in the cellular cytosol.
B)during passage through the mitochondrial outer membrane.
C)in the intermembrane space.
D)during passage through the inner mitochondrial membrane.
E)in the mitochondrial matrix.

Question 7

β-oxidation

A)is the second step in the oxidation of glucose.
B)is a process used to oxidize fatty acids.
C)occurs in the cytoplasm.
D)is a process used to digest some polysaccharides.
E)lengthens fatty acids by addition of two carbons.

Question 8

Each of the following citric acid cycle enzymes is subject to allosteric regulation except

A)isocitrate dehydrogenase.
B)α-ketoglutarate dehydrogenase.
C)malate dehydrogenase.
D)fumarate hydratase.
E)pyruvate dehydrogenase.

Question 9

Each of the following statements about the citric acid cycle is true except

A)Oxidation by transfer of electrons to coenzymes occurs at two steps.
B)Decarboxylation to release CO₂ occurs at two steps.
C)Substrate-level phosphorylation generates ATP/GTP at one step.
D)Acetate enters the citric acid cycle and joins a four-carbon acceptor molecule to form citrate.
E)The cycle involves the ordered activity of eight enzymes.

Question 10

Why are mitochondria so prevalent in skeletal muscle?

A)Mitochondria provide the muscle elasticity to contract.
B)Mitochondria are primarily involved in repairing damage accumulated during exercise.
C)Mitochondria provide energy for muscle contraction.
D)Mitochondria produce energy anaerobically.
E)More mitochondria are required in tissues where blood flow is restricted.

Question 11

High NADH concentration regulates pyruvate oxidative decarboxylation and the citric acid cycle by allosterically inhibiting interacting with each of the following enzymes except

A)pyruvate dehydrogenase.
B)isocitrate dehydrogenase.
C)α-ketoglutarate dehydrogenase.
D)malate dehydrogenase.
E)succinate dehydrogenase.

Question 12

Each of the following is a product of the citric acid cycle except

A)CO_2.
B)ATP.
C)NADH.
D)acetyl CoA.
E)FADH_2.

Question 13

Pyruvate is converted to acetyl CoA through the action of

A)pyruvate decarboxylase.
B)pyruvate dehydrogenase complex.
C)aconitase.
D)citrate synthase.
E)pyruvate CoA transferase.

Question 14

Which of the following citric acid cycle enzymes catalyzes substrate-level phosphorylation?

A)isocitrate dehydrogenase
B)α-ketoglutarate dehydrogenase
C)succinyl CoA synthetase
D)succinate dehydrogenase
E)malate dehydrogenase

Question 15

In plants and other eukaryotes that do not depend upon fatty acids as an energy source,β-oxidation occurs in the

A)cytoplasm.
B)mitochondrion.
C)glyoxysome
D)Golgi complex.
E)endosome.

Question 16

Each of the following citric acid cycle enzymes catalyzes electron transfer to NADH/FADH₂ except

A)isocitrate dehydrogenase.
B)α-ketoglutarate dehydrogenase.
C)succinyl CoA synthetase.
D)succinate dehydrogenase.
E)malate dehydrogenase.

Question 17

Which of the following molecules is incorrectly matched with the number of carbon atoms it possesses?

A)citrate; 6
B)α-ketoglutarate; 5
C)acetyl CoA; 2
D)malate; 5
E)isocitrate; 6

Question 18

Which of the following processes is associated with the outer mitochondrial membrane?

A)phospholipid synthesis
B)pyruvate oxidation
C)β-oxidation of fats
D)proton translocation for ATP synthesis
E)electron transport

Question 19

Because the citric acid cycle links degradation and synthesis,the pathway is classified as

A)anabolic.
B)amphibolic.
C)catabolic.
D)bipolar.
E)amphipathic.

Question 20

As pyruvate is prepared for the citric acid cycle,it undergoes a process of

A)reductive carboxylation.
B)oxidative decarboxylation.
C)oxidative carboxylation.
D)reductive decarboxylation.
E)substrate level phosphorylation.

Question 21

Supercomplexes of electron transport complexes are known as

A)Q complexes.
B)chemiosmotic coupling complexes.
C)Fe-S centers.
D)respirasomes.
E)NADH dehydrogenase complexes.

Question 22

Mitochondrial crista junctions

A)are large pores in the inner membrane.
B)are associated with the movement of material from the cytosol into the intermembrane space.
C)contain the mitochondrial DNA.
D)connect thylakoid membranes.
E)limit movement of material between the intracristal and intermembrane spaces.

Question 23

Each of the following could be the terminal electron acceptor in anaerobic respiration except

A)O₂.
B)sulfur.
C)protons.
D)iron.
E)All could serve as the terminal electron acceptor in anaerobic respiration.

Question 24

Aerobic respiration generates up to ________ ATP molecules per glucose molecule.

A)2
B)16
C)24
D)38
E)42

Question 25

Pyruvate dehydrogenase is regulated by all of the following except

A)NADH.
B)ATP.
C)AMP.
D)acetyl CoA.
E)CO_2.

Question 26

Ketosis is characterized by

A)depleted ketone body levels.
B)depleted free CoA levels.
C)fat oxidation to pyruvate.
D)blood pH increase.
E)All of the above are characteristic of ketosis.

Question 27

Each of the following complexes pumps protons out of the matrix to generate the proton gradient except

A)complex I.
B)complex II.
C)complex III.
D)complex IV.
E)coenzyme Q.

Question 28

The overall efficiency of aerobic respiration in eukaryotes is approximately

A)10%.
B)25%.
C)55%.
D)75%.
E)100%.

Question 29

In electron transport,each of the following respiratory complexes is involved in the flow of electrons from FADH₂ to O₂ except

A)complex I.
B)complex II.
C)complex III.
D)complex IV.
E)All are involved in the flow of electrons from FADH₂.

Question 30

Each of the following molecules is an electron carrier in the electron transport system except

A)flavoproteins.
B)iron-containing cytochromes.
C)iron-sulfur proteins.
D)coenzyme Q.
E)All of the above are electron carriers.

Question 31

Thermogenin in the inner membrane of brown fat cell mitochondria does all of the following except

A)decrease the proton gradient.
B)uncouple ATP synthesis from electron transport.
C)generate heat.
D)decrease ATP synthesis.
E)increase ATP synthesis.

Question 32

The form of fatty acid that is transported into the mitochondrion is

A)sulfated fatty acid.
B)fatty acyl CoA.
C)decarboxylated fatty acid residues.
D)triacylglycerols.
E)ketone bodies.

Question 33

Which of the following carrier molecules has a heme prosthetic group?

A)flavoproteins
B)iron-sulfur proteins
C)cytochromes
D)copper-containing cytochromes
E)coenzyme Q

Question 34

When electrons flow through the electron transport system from NADH to oxygen,what is the sequence of molecules through which they move?

A)complex I,cytochrome c,complex III,coenzyme Q,complex IV,O₂
B)complex I,coenzyme Q,complex III,complex IV,O₂
C)complex I,coenzyme Q,complex IV,cytochrome c,O₂
D)complex I,coenzyme Q,complex III,cytochrome c,complex IV,O₂
E)complex II,coenzyme Q,complex III,complex IV,O₂

Question 35

The Q cycle can

A)transport protons out of the matrix without additional electron transfer between complexes I and III.
B)associate with complex IV.
C)transfer electrons to O₂.
D)generate superoxide.
E)All of the above can be performed by the Q cycle.

Question 36

In electron transport,each of the following respiratory complexes is involved in the flow of electrons from NADH to O₂ except

A)complex I.
B)complex II.
C)complex III.
D)complex IV.
E)All are involved in the flow of electrons from NADH.

Question 37

Which of the following electron carriers transfers both protons and electrons?

A)cytochrome a
B)cytochrome b
C)coenzyme Q
D)iron-sulfur proteins
E)iron-copper proteins

Question 38

The chemiosmotic model of ATP synthesis is based on each of the following lines of experimental evidence except

A)Artificial proton gradients established by addition of acid can drive ATP synthesis in the absence of electron transport.
B)Oxidative phosphorylation does not require a membrane-enclosed compartment.
C)Electron transport causes protons to be pumped out of the mitochondrial matrix.
D)The proton gradient established by electron transport has enough energy to drive ATP synthesis.
E)Uncoupling agents abolish both the proton gradient and ATP synthesis.

Question 39

Each of the following numbered respiratory complexes is correctly paired with its name except

A)complex I: NADH-coenzyme Q oxidoreductase complex.
B)complex II: succinate-coenzyme Q oxidoreductase complex.
C)complex III: coenzyme Q-cytochrome c oxidoreductase complex.
D)complex IV: cytochrome c reductase complex.
E)None of the above are correctly paired.

Question 40

The citric acid cycle and glyoxylate cycle are similar in many respects.Which of the following statements accurately describes these cycles?

A)Both cycles are catabolic.
B)The glyoxylate cycle has only a single decarboxylating reaction.
C)In the glyoxylate cycle,two acetyl CoA molecules are used to generate succinate.
D)The glyoxylate cycle is used by some organisms to synthesize proteins.
E)The citric acid and glyoxylate cycles both occur in the mitochondrion.

Question 41

The maximum yield of ATP per molecule of glucose in eukaryotic cells is 36 or 38 ATP,depending on cell type and conditions.In prokaryotic cells,the maximum yield is 38 ATP.
a.The maximum yield of ATP in eukaryotic heart muscle cells is 38,but in skeletal muscle cells the yield is only 36.What is the basis for this difference?
b.Why is the maximal ATP yield for prokaryotic cells 38 and not 36?
c.Why is the calculated ATP yield referred to as "Maximal Theoretical Yield" in eukaryotic and in prokaryotic cells?

Question 42

The citric acid cycle is also known as the ________ cycle after the individual whose laboratory elucidated the sequence in the 1930s.

Question 43

Mitochondrial DNA replication occurs in the ________ of the mitochondrion.

Question 44

Protruding from the inner membrane of the mitochondria into the matrix are knoblike spheres called ________ complexes,which are attached by a short protein stalk to a(n)________ complex.Together these complexes are referred to as the ________ complex.

Question 45

Directional pumping of protons during electron transport establishes a(n)________ across the inner mitochondrial membrane.

Question 46

________ is the oxidation-driven flow of electrons through or within a membrane from reduced coenzymes to an electron acceptor,which is usually accompanied by the generation of ATP.

Question 47

Respiration includes glycolysis,the ________,electron transport,and ________.

Question 48

NAD contains the B vitamin niacin as part of its structure,whereas FAD contains another B vitamin,________,as part of its structure.

Question 49

The F_oF₁ synthesis of ATP depends on delivery of electrons carried by NADH and FADH₂ to electron transport systems in the inner mitochondrial membrane in eukaryotic cells or in the plasma membrane of prokaryotic cells.What is the maximum number of ATPs generated for the following?
a.one molecule of FADH₂ produced during the citric acid cycle
b.one molecule of NADH produced during the citric acid cycle
c.one molecule of NADH produced by glycolysis in a muscle cell that uses the mitochondrial glycerol phosphate shuttle
d.one molecule of NADH produced by glycolysis in a liver cell using the mitochondrial malate-aspartate shuttle
e.one molecule of FADH₂ produced during the citric acid cycle in a prokaryotic cell
f.one molecule of NADH produced by glycolysis in a prokaryotic cell

Question 50

Pyruvate crosses the ________ and the ________ membranes prior to its oxidation during respiration.

Question 51

Using Table 10-2 values,(a)what do you predict from the standard reduction potentials about the direction electrons will tend to flow between NADH and O₂,and (b)using the equation calculate the standard free energy change (?G^{°)associated with the transfer of electrons between NADH and O}₂^.
Reaction: O₂ + 2 NADH + 2H^{+ = 2 H}₂O ^{+ 2 NAD+}
Equation: ?G° = ?nF?E0' [n is the number of electrons transferred; F is the Faraday constant (23,062 cal/mol-V)

Question 52

The reduction of NAD⁺ to NADH occurs both in the ________ and in the ________ of the ________.

Question 53

Both thermogenin and 2,4-dinitrophenol (DNP)uncouple oxidation from ATP synthesis.Thermogenin is expressed in the mitochondria of brown fat cells in newborn animals and adult mammals that hibernate.DNP was marketed in the 1930s as a diet pill,but in addition to causing weight loss it sometimes caused death.
a.Compare the mechanisms by which these uncouplers affect ATP synthesis.
b.What function does thermogenin serve for brown fat cells?
c.Why is the rationale for DNP as a diet drug?
d.Considering locations of the effects in an animal and the possibility for allosteric regulation,suggest why thermogenin is advantageous and DNP dangerous for humans?

Question 54

ATP synthesis that involves phosphorylation events linked to O₂-dependent electron transport is called ________.

Question 55

________ is a lower-energy citric acid coenzyme than NAD⁺.

Question 56

The ATP synthase F_o complex is inhibited by the antibiotic ________,as indicated by the "o."

Question 57

The outer membrane of the mitochondrion is not a significant permeability barrier because it contains transmembrane proteins called ________.

Question 58

Multiprotein complexes known as ________ minimize diffusion distances and facilitate electron flow between electron transport complexes.