Deck 6: Cellular Respiration

Question 1

In the process of aerobic metabolism, carbon-containing molecules are broken down. What is the energy from the electrons used for?

A)to generate a hydrogen ion gradient
B)to heat the organism in a cold environment
C)to alter enzyme structure
D)to directly supply the energy needs of an organism

Answer 1

A

Question 2

Which statement best describes the function of NADH and FADH₂?

A)Both produce ATP by substrate-level phosphorylation.
B)Both transport acetyl-CoA to mitochondria.
C)Both provide electrons to the electron transfer system.
D)Both release energy for glycolysis to proceed.

Answer 2

C

Question 3

The electrons that are present in NADH and FADH₂ are very high energy and theoretically sufficient to produce ATP alone. Why then have biological systems evolved a way that uses the various steps of cellular respiration to produce ATP?

A)because steps in respiration allow for a controlled release of energy in small increments
B)because all living organisms must use oxygen and therefore must carry out cellular respiration
C)because it would be less efficient to produce ATP directly from NADH and FADH₂
D)because the amount of ADP is insufficient to phosphorylate and make ATP

Answer 3

A

Question 4

Which of the following best explains why food is not energy?

A)Energy is exhaustive, and food is not.
B)Food is exhaustive, and energy is not.
C)Food can make us fat, and energy cannot.
D)Energy can make us fat, and food cannot.

Question 5

Which of the following processes actually produces a significant quantity of ATP?

A)pyruvate oxidation
B)glycolysis
C)oxidative phosphorylation
D)the citric acid cycle

Question 6

In which way are NADH and FADH₂ related?

A)They both carry high-energy phosphates.
B)They both carry high-energy electrons.
C)They are both used in glycolysis.
D)They both directly produce ATP.

Question 7

What is the final product of glycolysis?

A)fructose
B)glyceraldehyde-3-phosphate
C)pyruvate
D)glucose

Question 8

Which of the following best explains the energetic status of cellular respiration?

A)It is an exergonic process, with negative free energy.
B)It is an endergonic process, with negative free energy.
C)It is an exergonic process, with positive free energy.
D)It is an endergonic process, with negative free energy.

Question 9

Which cellular respiration process is absolutely dependent upon a supply of NADH?

A)glycolysis
B)the electron transfer system
C)pyruvate oxidation
D)the citric acid cycle

Question 10

When individuals have mitochondrial disorders, the skeletal and heart muscles and the brain are the parts of the body that are most affected. Why are these the parts that are most affected?

A)because they have the highest energy needs
B)because they are generally very fragile
C)because they are the most important organs
D)because they have fewer mitochondria in the cell

Question 11

For a molecule to be reduced, it can gain electrons from the environment. In what other way can a molecule be reduced?

A)by losing hydrogens
B)by losing oxygen
C)by gaining oxygen
D)by gaining hydrogens

Question 12

Which of the following is the best line of evidence for glycolysis being an ancient pathway?

A)Glycolysis occurs in mitochondria.
B)Glycolysis is universal.
C)Glycolysis is highly regulated.
D)Glycolysis is complicated.

Question 13

What is the final product of glycolysis?

A)1 molecule of pyruvate
B)2 molecules of pyruvate
C)1 molecule of glyceraldehyde-3-phosphate
D)2 molecules of glyceraldehyde-3-phosphate

Question 14

Which molecules are responsible for delivering the high-energy electrons from the citric acid cycle to the electron transfer system?

A)Cyt C and Q
B)NADH and Cyt C
C)FADH₂ and Q
D)NADH and FADH₂

Question 15

If glycolysis is considered universal, which of the following illustrates that?

A)Glycolysis occurs in Archaea, Bacteria, and Eukarya.
B)Glycolysis occurs in Archaea and Eukarya.
C)Glycolysis occurs in Bacteria and Eukarya.
D)Glycolysis occurs in Archaea and Bacteria.

Question 16

Which of the following chemical reactions are common in cellular respiration?

A)reduction/oxidation
B)bimolecular/trimolecular
C)exothermic/endothermic
D)acid/base

Question 17

Glycolysis can take place in the absence of which of the following small molecules?

A)FAD
B)ATP
C)NAD⁺
D)ADP

Question 18

Glycolysis can take place in the absence of which of the following small molecules?

A)ATP
B)Oxygen
C)NAD⁺
D)ADP

Question 19

Which of the following is the ultimate source of chemical energy for all living organisms?

A)glucose
B)photosynthesis
C)GTP
D)cellular respiration

Question 20

It has been thought that many diseases now associated with aging are related to malfunctioning mitochondria. Why are the mitochondria so important to all cells?

A)They generate heat to keep the body warm.
B)They produce energy in the form of ATP.
C)They are extremely large.
D)They are ancestral and were acquired by symbiosis.

Question 21

Ultimately, the carbon molecules in pyruvate become integrated into which of the following molecules?

A)CoA
B)ATP
C)CO₂
D)acetate

Question 22

What molecule is a product of glycolysis, pyruvate oxidation, and the citric acid cycle?

A)ATP
B)FADH₂
C)NADH
D)H₂O

Question 23

Which chemical characteristic makes phosphoenolpyruvate (PEP) unusual?

A)PEP regulates the activity of phosphofructokinase.
B)PEP can carry out redox reactions.
C)PEP provides high-energy electrons to make ATP.
D)PEP supplies a high-energy phosphate to phosphorylate ADP.

Question 24

Which piece of the ATP synthase contains the channel for H⁺ to flow through?

A)the stalk
B)the basal unit
C)the headpiece
D)the lollipop

Question 25

Which phrase best describes the proton-motive force?

A)the amount of energy required to protonate a glucose molecule
B)the force needed to move protons into the inner mitochondrial space
C)the free energy associated with the removal of hydrogen from NADH
D)the combination of a proton and voltage gradient across the membrane

Question 26

During which stage of cellular respiration is CO₂ released?

A)during the citric acid cycle
B)during glycolysis
C)during electron transport system
D)during both pyruvate oxidation and the citric acid cycle

Question 27

Which of the following directly supply the electrons for the electron transfer system?

A)FADH₂ and NADH
B)pyruvate and acetate
C)ATP and ADP
D)various enzymes

Question 28

What is the purpose of the last stage of the citric acid cycle?

A)to replenish the supplies of NAD⁺ and FAD
B)to break down glucose into a three-carbon molecule
C)to regenerate oxaloacetate to attach to another acetyl molecule
D)to produce ATP by substrate-level phosphorylation

Question 29

Which of the following molecules is responsible for carrying the acetyl group from pyruvate into the citric acid cycle?

A)FADH₂
B)ATP
C)CoA
D)NADH

Question 30

Which phrase best describes what occurs during chemiosmosis?

A)the synthesis of ATP by ATP synthase using a proton gradient
B)the buildup of acetate in the cytoplasm in the absence of oxygen
C)the breakdown of oxygen as it enters the mitochondria
D)the production of NADH and FADH₂ in cellular respiration

Question 31

Which of the following are directly responsible for pumping protons out of the matrix in the mitochondria?

A)cytochrome c, ubiquinone, and protein complex II
B)cytochrome c, and protein complexes I and III
C)protein complexes I, III, and IV
D)ubiquinone, and protein complexes I and IV

Question 32

What are the functions of cytochrome c and ubiquinone?

A)They shuttle electrons between the protein complexes.
B)They synthesize water from molecular oxygen.
C)They translocate protons from the matrix to the inner mitochondrial space.
D)They produce ATP by substrate-level phosphorylation.

Question 33

Which of the following directly powers the ATP synthase?

A)carbohydrate metabolism
B)NADH/FADH₂
C)the proton gradient
D)electron transfer

Question 34

Which phrase best describes the chemical conditions inside the mitochondrial matrix?

A)low pH and high pyruvate concentration
B)high pH and high pyruvate concentration
C)high pH and low pyruvate concentration
D)low pH and low pyruvate concentration

Question 35

Suppose that the pH of the matrix was significantly lower than the inner mitochondrial space. How would the ATP synthase function differently?

A)It would misfold.
B)It would no longer function properly.
C)It would require an ion to stabilize it.
D)It would hydrolyze ATP to form ADP.

Question 36

For every glucose molecule that goes through cellular respiration, how many times is a carbon molecule fully oxidized to CO₂ in the citric acid cycle?

A)4 times
B)3 times
C)2 times
D)1 time

Question 37

Which phrase describes the mechanism that facilitates the passage of electrons between protein complexes in the mitochondrial inner membrane?

A)The oxidized electron carrier protein passes on the electron to FADH and becomes reduced.
B)The reduced electron carrier protein passes on the electron to the next protein and becomes oxidized.
C)The reduced electron carrier protein passes on the electron to FADH and becomes oxidized.
D)The oxidized electron carrier protein passes on the electron to the next protein and becomes reduced.

Question 38

Suppose all the protons that powered the ATP synthase were NOT dealt with in some fashion: the proton gradient would be destroyed and ATP could no longer be produced by oxidative phosphorylation. Which statement describes what happens to these protons as they re-enter the matrix?

A)They help in the production of CO₂.
B)They are attached to NAD⁺ and FAD.
C)They synthesize ATP by substrate-level phosphorylation.
D)They combine with oxygen to form water.

Question 39

Where is ATP synthase located in eukaryotic cells?

A)in the matrix of the mitochondria
B)in the outer membrane of the cell
C)in the nuclear envelope
D)in the inner mitochondrial membrane

Question 40

What is the fate of CoA after it delivers an acetyl group into the citric acid cycle?

A)It is used in protein synthesis.
B)It remains in an inactive form until the cell dies.
C)It is degraded and used for energy.
D)It is recharged with another acetate.

Question 41

Both plants and animals possess mitochondria, which are used for cellular respiration to make ATP.

Question 42

How many catalytic sites does the ATP synthase have?

A)1
B)2
C)3
D)4

Question 43

Glycolysis takes place in the mitochondria.

Question 44

Which part of the ATP synthase is responsible for catalyzing ATP formation?

A)the basal unit
B)the stalk
C)the headpiece
D)the lollipop

Question 45

Molecular oxygen is breathed in and expired as carbon dioxide.

Question 46

Refer to the above illustration of a mitochondrion. Match the labelled parts of the mitochondrion with the steps of cellular respiration. A labelled part may be used once, more than once, or not at all.
a.outer mitochondrial membrane
b.intermembrane compartment
c.cytosol
d.inner mitochondrial membrane
e.matrix
oxidative phosphorylation

Question 47

Suppose it is true that potato plants use uncoupling proteins (UCPs) in a way that is similar to how mammals use them. What would a researcher expect to observe in these plants?

A)increased amounts of ATP production
B)decreased mitochondrial catabolism
C)increased internal tissue temperature
D)decreased sugar metabolism

Question 48

How efficient is cellular respiration in extracting the energy stored in the bonds of glucose?

A)close to 60% efficient
B)close to 40% efficient
C)close to 20% efficient
D)close to 10% efficient

Question 49

If, during a chemical reaction, a molecule loses hydrogens, it could be described as being oxidized.

Question 50

Two mobile electron carriers that are important for the electron transfer system are cytochrome c and ubiquinone.

Question 51

During the process of pyruvate oxidation, pyruvate is broken down and the remaining two carbons are attached to coenzyme A.

Question 52

Why do cells go through fermentation?

A)to replenish NAD⁺
B)to replenish O₂
C)to replenish FAD
D)to replenish NADH

Question 53

The main purpose of fermentation is to regenerate NADH and FADH₂.

Question 54

During pyruvate oxidation, one molecule of ATP is produced.

Question 55

Oxygen acts as a final electron acceptor in respiration. Which molecule is it ultimately converted into?

A)water
B)CO₂
C)ATP
D)glucose

Question 56

During glycolysis, ATP is produced by oxidative phosphorylation.

Question 57

Refer to the above illustration of a mitochondrion. Match the labelled parts of the mitochondrion with the steps of cellular respiration. A labelled part may be used once, more than once, or not at all.
a.outer mitochondrial membrane
b.intermembrane compartment
c.cytosol
d.inner mitochondrial membrane
e.matrix
pyruvate oxidation

Question 58

What is the proton-motive force used for?

A)diffusing substances across membranes and driving movement of flagella in bacteria
B)pumping substances across membranes and driving movement of flagella in eukaryotes
C)pumping substances across membranes and driving movement of flagella in bacteria
D)diffusing substances across membranes and driving movement of flagella in eukaryotes

Question 59

Consider the contribution of NADH and FADH₂. How many of the 38 total ATP molecules produced in cellular respiration come from the citric acid cycle?

A)20
B)22
C)28
D)32

Question 60

Which of the following analogies best illustrates the answer to the following: If sugars contain energy, why do we have to break apart sugars to release energy in order to make the high energy chemical called ATP?

A)electrons of matter
B)photons of light
C)letters in the word
D)books in the library

Question 61

Refer to the above illustration of a mitochondrion. Match the labelled parts of the mitochondrion with the steps of cellular respiration. A labelled part may be used once, more than once, or not at all.
a.outer mitochondrial membrane
b.intermembrane compartment
c.cytosol
d.inner mitochondrial membrane
e.matrix
citric acid cycle

Question 62

Refer to the above illustration of a mitochondrion. Match the labelled parts of the mitochondrion with the steps of cellular respiration. A labelled part may be used once, more than once, or not at all.
a.outer mitochondrial membrane
b.intermembrane compartment
c.cytosol
d.inner mitochondrial membrane
e.matrix
electron transfer system

Question 63

Refer to the above illustration of a mitochondrion. Match the labelled parts of the mitochondrion with the steps of cellular respiration. A labelled part may be used once, more than once, or not at all.
a.outer mitochondrial membrane
b.intermembrane compartment
c.cytosol
d.inner mitochondrial membrane
e.matrix
ATP synthesis

Question 64

Refer to the above illustration of a mitochondrion. Match the labelled parts of the mitochondrion with the steps of cellular respiration. A labelled part may be used once, more than once, or not at all.
a.outer mitochondrial membrane
b.intermembrane compartment
c.cytosol
d.inner mitochondrial membrane
e.matrix
glycolysis