Deck 10: Chemotrophic Energy Metabolism: Aerobic Respiration

Question 1

Of the following enzymes associated with the TCA cycle,which of the following enzymes is not under allosteric regulation?

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

Answer 1

D

Question 2

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

A)reductive carboxylation.
B)oxidative decarboxylation.
C)oxidative carboxylation.
D)reductive decarboxylation.
E)CoQ reproduction.

Answer 2

B

Question 3

Why are mitochondria so prevalent in skeletal muscle?

A)They give the muscle enough elasticity to contract.
B)They are needed to repair damaged tissue that accumulates during exercise.
C)They are needed to provide energy for muscle contraction.
D)Bones and muscles require a great deal of energy to prevent them from separating.
E)The flow of blood is greatest in skeletal muscle.

Answer 3

C

Question 4

During which of the following steps of the TCA cycle does substrate-level phosphorylation take place?

A)TCA-2
B)TCA-3
C)TCA-4
D)TCA-5
E)TCA-6

Question 5

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

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

Question 6

NADH concentrations serve to regulate oxidative decarboxylation and the TCA cycle.Which of the following enzymes is not regulated by NADH?

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

Question 7

Which molecule 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 8

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

A)phospholipid synthesis
B)metabolite transport
C)β-oxidation of fats
D)transcription
E)ATP synthesis

Question 9

Pyruvate is converted to acetyl CoA by a unique enzyme known as

A)pyruvate decarboxylase.
B)pyruvate dehydrogenase complex.
C)transitionase system.
D)multiplex enzyme system.
E)pyruvate CoA transferase.

Question 10

Which of the following structures serves the same purpose as the inner membrane and matrix of the mitochondrion with regard to their roles in aerobic respiration?

A)ribosomes
B)cell membrane
C)cytoplasm
D)nuceloid
E)both choices B and C

Question 11

In eukaryotes,pyruvate is converted to acetyl CoA

A)in the cellular cytosol.
B)when passing through the mitochondrial outer membrane.
C)in the intermembrane space.
D)when passing the mitochondrial cristae.
E)in the mitochondrial matrix.

Question 12

If a eukaryotic organism does not depend on fatty acids as an energy source,one would expect to find β-oxidation activity associated with which of the following organelles?

A)cytoplasm
B)mitochondrion
C)peroxisome
D)ribosome
E)cell membrane

Question 13

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)both choices B and C

Question 14

According to your text,in which of the following steps of the TCA cycle is NADH/FADH₂ not produced?

A)TCA-2
B)TCA-3
C)TCA-4
D)TCA-6
E)TCA-8

Question 15

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

A)sodium-potassium pump
B)dicarboxylate carriers
C)tricarboxylate carriers
D)pyruvate carrier cotransport
E)ATP-ADP carrier exchange

Question 16

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

A)TCA cycle; pyruvate
B)glycolysis; fructose-6-phosphate
C)TCA cycle; acetyl CoA
D)electron transport system; CoQ
E)glycolysis; dihydroxyacetone phosphate

Question 17

Which of the following is not a product of the TCA cycle?

A)CO₂
B)ATP
C)NADH
D)acetyl CoA
E)FADH₂

Question 18

Because the TCA cycle is associated with degradation and synthesis,the pathway is said to be

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

Question 19

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

A)hydration
B)reoxidation
C)thiolysis
D)acylation
E)oxidation

Question 20

Which of the following statements is not true of the TCA cycle?

A)Oxidation occurs at three steps in the TCA cycle.
B)Decarboxylation occurs at two steps in the TCA cycle.
C)ATP/GTP is generated at one point by substrate-level phosphorylation.
D)Acetate enters the TCA cycle and joins a four-carbon acceptor molecule to form citrate.
E)FAD is an electron acceptor in the cycle.

Question 21

Which of the following molecules is not a carrier of electrons in the electron transport system (ETS)?

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

Question 22

Which of the following would not be used as a final electron acceptor in anaerobic respiration?

A)oxygen
B)sulfur
C)protons
D)iron
E)nitrogen

Question 23

The chemiosmotic model of ATP synthesis is based on several lines of experimental evidence.Which of the following statements is not correct experimental evidence to support the chemiosmotic model?

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 24

Of the carrier molecules in the electron transport chain,which has heme as part of its prosthetic group?

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

Question 25

In electron transport,which respiratory complex is not involved in the flow of electrons from NADH?

A)complex I
B)complex II
C)complex III
D)complex IV
E)all of the above

Question 26

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)phospholipids.

Question 27

Which of the numbered respiratory complexes is not correctly paired with its name?

A)complex I: NADH dehydrogenase 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

Question 28

The overall efficiency of aerobic respiration in eukaryotes is about

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

Question 29

Pyruvate dehydrogenase is regulated by all of the following except

A)NADH.
B)ATP.
C)AMP.
D)acetyl CoA.
E)CO₂.

Question 30

Crista junctions

A)are large pores.
B)are associated with the movement of materials from the cytosol into the mitochondrion.
C)contain the mitochondrial DNA.
D)are associated with the thylakoid membrane system.
E)limit the movement of products between the intracristae and intermembrane spaces.

Question 31

In electron transport,which respiratory complex is not involved in the flow of electrons from FADH₂?

A)complex I
B)complex II
C)complex III
D)complex IV
E)all of the above

Question 32

Of the following sequences,which shows the correct molecules through which electrons flow when delivered to the electron transport system by NADH?

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

Question 33

The condition known as ketosis is characterized by

A)depleted ketobody levels
B)depleted CoA levels
C)fat oxidation to CO₂.
D)increases in blood pH
E)both choices A and D

Question 34

The Q cycle

A)allows for the movement of protons without additional electrons.
B)is associated with complex I.
C)mediates the transfer of electrons to oxygen.
D)accounts for the generation of superoxide.
E)all of the above

Question 35

In brown fat,________ present in the inner mitochondrial membrane uncouples ATP synthesis from electron transport in infants and other newborn mammals.

A)thermogenin
B)fluorocitrate
C)coenzyme A
D)submitochondrial particles
E)respirasomes

Question 36

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

A)Both cycles are catabolic in function.
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 TCA and glyoxylate cycles both occur in the mitochondrion.

Question 37

In prokaryotes,aerobic respiration generates ________ ATP molecules.

A)2
B)15
C)38
D)42
E)0

Question 38

Multiple protein complexes associated with the cellular respiration are known as

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

Question 39

Proton gradients are generated by all of the following complexes except

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

Question 40

Of the following electron carriers of the electron transport system,which transfers protons in addition to electrons?

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

Question 41

In the case of the Fo complex,the "o" refers to the antibiotic ________,to which the structure is sensitive.

Question 42

While electron transport is occurring,the development of a(n)________ is established by the directional pumping of protons across the inner membrane of the mitochondrion.

Question 43

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

Question 44

________ (FAD)is a molecule similar to NAD⁺ in function,but it is a lower-energy coenzyme.

Question 45

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

Question 46

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

Question 47

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

Question 48

Explain how fatty acids are activated in the cytoplasm and ultimately transported into the mitochondrion to be oxidized.Why would the use of carnitine be an advantage for this process?

Question 49

The site of DNA replication is localized to the ________ within the mitochondrion.

Question 50

Multiprotein respiratory complexes,known as ________,function to minimize diffusion distances and facilitate electron flow between the rspiratory complexes.

Question 51

The maximum yield of ATP per molecule of glucose in eukaryotic cells is 36 or 38 ATP.In prokaryotic cells,the maximum yield is 38 ATP.
a. From what you know about prokaryotes and eukaryotes,suggest why there is a difference in maximum ATP production.
b. The yield of ATP varies in eukaryotes from 36 to 38 ATP.Why is there a variation?
c. Why is ATP yield clarified with "maximum"?

Question 52

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 53

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

Question 54

The ________ (TCA)cycle is also known as the ________ cycle after the individual whose laboratory elucidated the sequence in the 1930s.

Question 55

The synthesis of ATP as a result of the electron transport system is dependent on the delivery of electrons and hydrogen ions by NADH and FADH₂ to the inner membrane of the mitochondria in eukaryotic cells or the cell membrane of prokaryotic cells.For each of the situations below,give the maximum number of ATP generated.
a.one molecule of FADH₂ produced during the TCA cycle
b.one molecule of NADH produced during the TCA cycle
c.one molecule of NADH produced by glycolysis in a muscle cell that has a very low cytoplasmic level of NADH
d.one molecule of NADH produced by glycolysis in a liver cell using the malate-aspartate shuttle
e.one molecule of FADH2 produced during the TCA cycle in a prokaryotic cell
f.one molecule of NADH produced by glycolysis in a prokaryotic cell

Question 56

Pyruvate passes freely across some intracellular membranes.The membranes of the ________ must be crossed by pyruvate prior to its oxidation during respiration.

Question 57

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

Question 58

Thermogenin and 2,4-dinitrophenol (DNP)are both uncoupling agents. Thermogenin is found in newborn animals and some adult mammals.DNP was marketed in the 1930s as a diet pill.However,DNP treatment not only resulted in weight loss but also death of the patient.Based on this information,how do uncouplers disrupt electron transport/chemiosmosis? Why do thermogenin and DNP result in such different outcomes when both work via a similar mechanism?

Question 59

Calculate the standard free energy change (ΔG°)associated with the transfer of electrons from NADH and O2 using the following equation:
O2 + 2 NADH + 2H+ = 2 H20 + 2 NAD+
The half equations are : O2 + 4H + 4e- → 2H2O, E0' = 0.82V; NAD + H + 2e- → NADH, E0' = -0.32V