Name: 
 

Chapter 9 - Cellular Respiration


Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction
a.
gains electrons and gains energy.
b.
loses electrons and loses energy.
c.
gains electrons and loses energy.
d.
loses electrons and gains energy.
e.
neither gains nor loses electrons, but gains or loses energy.
 

 2. 
Why does the oxidation of organic compounds by molecular oxygen to produce mc002-1.jpg and water release free energy?
a.
The covalent bonds in organic molecules are higher energy bonds than those in water and carbon dioxide.
b.
Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O).
c.
The oxidation of organic compounds can be used to make ATP.
d.
The electrons have a higher potential energy when associated with water and mc002-2.jpg than they do in organic compounds.
e.
The covalent bond in mc002-3.jpg is unstable and easily broken by electrons from organic molecules.
 

 3. 
Which of the following statements describes the results of this reaction?
mc003-1.jpg
a.
mc003-2.jpg is oxidized and mc003-3.jpg is reduced.
b.
mc003-4.jpg is oxidized and mc003-5.jpg is reduced.
c.
mc003-6.jpg is reduced and mc003-7.jpg is oxidized.
d.
mc003-8.jpg is reduced and mc003-9.jpg is oxidized.
e.
mc003-10.jpg is reduced and mc003-11.jpg is oxidized.
 

 4. 
Where does glycolysis takes place?
a.
mitochondrial matrix
b.
mitochondrial outer membrane
c.
mitochondrial inner membrane
d.
mitochondrial intermembrane space
e.
cytosol
 

 5. 
The ATP made during glycolysis is generated by
a.
substrate-level phosphorylation.
b.
electron transport.
c.
photophosphorylation.
d.
chemiosmosis.
e.
oxidation of NADH to NADmc005-1.jpg.
 

 6. 
The oxygen consumed during cellular respiration is involved directly in which process or event?
a.
glycolysis
b.
accepting electrons at the end of the electron transport chain
c.
the citric acid cycle
d.
the oxidation of pyruvate to acetyl CoA
e.
the phosphorylation of ADP to form ATP
 

 7. 
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
a.
electron transport
b.
glycolysis
c.
the citric acid cycle
d.
oxidative phosphorylation
e.
chemiosmosis
 

 8. 
An electron loses potential energy when it
a.
shifts to a less electronegative atom.
b.
shifts to a more electronegative atom.
c.
increases its kinetic energy.
d.
increases its activity as an oxidizing agent.
e.
attaches itself to NADmc008-1.jpg.
 

 9. 
Why are carbohydrates and fats considered high energy foods?
a.
They have a lot of oxygen atoms.
b.
They have no nitrogen in their makeup.
c.
They can have very long carbon skeletons.
d.
They have a lot of electrons associated with hydrogen.
e.
They are easily reduced.
 

 10. 
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed during glycolysis?
a.
0%
b.
2%
c.
10%
d.
38%
e.
100%
 

 11. 
During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is
a.
transferred to ADP, forming ATP.
b.
transferred directly to ATP.
c.
retained in the pyruvate.
d.
stored in the NADH produced.
e.
used to phosphorylate fructose to form fructose-6-phosphate.
 

 12. 
In addition to ATP, what are the end products of glycolysis?
a.
mc012-1.jpg and mc012-2.jpg
b.
mc012-3.jpg and pyruvate
c.
NADH and pyruvate
d.
mc012-4.jpg and NADH
e.
mc012-5.jpg, mc012-6.jpg, and citrate
 

 13. 
Starting with one molecule of glucose, the "net" products of glycolysis are
a.
2 NADmc013-1.jpg, 2 Hmc013-2.jpg, 2 pyruvate, 2 ATP, and 2 mc013-3.jpg.
b.
2 NADH, 2 Hmc013-4.jpg, 2 pyruvate, 2 ATP, and 2 mc013-5.jpg.
c.
2 mc013-6.jpg, 2 pyruvate, 4 ATP, and 2 mc013-7.jpg.
d.
6 mc013-8.jpg, 6 mc013-9.jpg, 2 ATP, and 2 pyruvate.
e.
6 mc013-10.jpg, 6 mc013-11.jpg, 36 ATP, and 2 citrate.
 

 14. 
In glycolysis, for each molecule of glucose oxidized to pyruvate
a.
2 molecules of ATP are used and 2 molecules of ATP are produced.
b.
2 molecules of ATP are used and 4 molecules of ATP are produced.
c.
4 molecules of ATP are used and 2 molecules of ATP are produced.
d.
2 molecules of ATP are used and 6 molecules of ATP are produced.
e.
6 molecules of ATP are used and 6 molecules of ATP are produced.
 

 15. 
Why is glycolysis described as having an investment phase and a payoff phase?
a.
It both splits molecules and assembles molecules.
b.
It attaches and detaches phosphate groups.
c.
It uses glucose and generates pyruvate.
d.
It shifts molecules from cytosol to mitochondrion.
e.
It uses stored ATP and then forms a net increase in ATP.
 
 
Use the following information to answer the next questions.

In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate 1) loses a carbon, which is given off as a molecule of nar002-1.jpg, 2) is oxidized to form a two-carbon compound called acetate, and 3) is bonded to coenzyme A.
 

 16. 
These three steps result in the formation of
a.
acetyl CoA, mc016-1.jpg, and ATP.
b.
acetyl CoA, mc016-2.jpg, and mc016-3.jpg.
c.
acetyl CoA, FAD, mc016-4.jpg, and mc016-5.jpg.
d.
acetyl CoA, NADH, Hmc016-6.jpg, and mc016-7.jpg.
e.
acetyl CoA, NADmc016-8.jpg, ATP, and mc016-9.jpg.
 

 17. 
Why is coenzyme A, a sulfur containing molecule derived from a B vitamin, added?
a.
because sulfur is needed for the molecule to enter the mitochondrion
b.
in order to utilize this portion of a B vitamin which would otherwise be a waste product from another pathway
c.
to provide a relatively unstable molecule whose acetyl portion can readily bind to oxaloacetate
d.
because it drives the reaction that regenerates NADmc017-1.jpg
e.
in order to remove one molecule of mc017-2.jpg
 

 18. 
How does pyruvate enter the mitochondrion?
a.
active transport
b.
diffusion
c.
facilitated diffusion
d.
through a channel
e.
through a pore
 

 19. 
Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (mc019-1.jpg) from one molecule of pyruvate?
a.
lactate
b.
glyceraldehydes-3-phosphate
c.
oxaloacetate
d.
acetyl CoA
e.
citrate
 

 20. 
During cellular respiration, acetyl CoA accumulates in which location?
a.
cytosol
b.
mitochondrial outer membrane
c.
mitochondrial inner membrane
d.
mitochondrial intermembrane space
e.
mitochondrial matrix
 

 21. 
A young animal has never had much energy. He is brought to a veterinarian for help and is sent to the animal hospital for some tests. There they discover his mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of his condition?
a.
His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.
b.
His cells cannot move NADH from glycolysis into the mitochondria.
c.
His cells contain something that inhibits oxygen use in his mitochondria.
d.
His cells lack the enzyme in glycolysis that forms pyruvate.
e.
His cells have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA.
 

 22. 
Cellular respiration harvests the most chemical energy from which of the following?
a.
substrate-level phosphorylation
b.
chemiosmotic phosphorylation
c.
converting oxygen to ATP
d.
transferring electrons from organic molecules to pyruvate
e.
generating carbon dioxide and oxygen in the electron transport chain
 

 23. 
During aerobic respiration, electrons travel downhill in which sequence?
a.
food ® citric acid cycle ® ATP ® NAD+
b.
food ® NADH ® electron transport chain ® oxygen
c.
glucose ® pyruvate ® ATP ® oxygen
d.
glucose ® ATP ® electron transport chain ® NADH
e.
food ® glycolysis ® citric acid cycle ® NADH ® ATP
 

 24. 
Where are the proteins of the electron transport chain located?
a.
cytosol
b.
mitochondrial outer membrane
c.
mitochondrial inner membrane
d.
mitochondrial intermembrane space
e.
mitochondrial matrix
 

 25. 
The primary role of oxygen in cellular respiration is to
a.
yield energy in the form of ATP as it is passed down the respiratory chain.
b.
act as an acceptor for electrons and hydrogen, forming water.
c.
combine with carbon, forming mc025-1.jpg.
d.
combine with lactate, forming pyruvate.
e.
catalyze the reactions of glycolysis.
 

 26. 
During oxidative phosphorylation, mc026-1.jpg is formed. Where does the oxygen for the synthesis of the water come from?
a.
carbon dioxide (mc026-2.jpg)
b.
glucose (mc026-3.jpg)
c.
molecular oxygen (mc026-4.jpg)
d.
pyruvate (mc026-5.jpg-)
e.
lactate (mc026-6.jpg-)
 

 27. 
In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + mc027-1.jpg to ATP?
a.
energy released as electrons flow through the electron transport system
b.
energy released from substrate-level phosphorylation
c.
energy released from ATP synthase pumping hydrogen ions from the mitochondrial matrix
d.
energy released from movement of protons through ATP synthase
e.
No external source of energy is required because the reaction is exergonic.
 

 28. 
Energy released by the electron transport chain is used to pump H+ ions into which location?
a.
cytosol
b.
mitochondrial outer membrane
c.
mitochondrial inner membrane
d.
mitochondrial intermembrane space
e.
mitochondrial matrix
 

 29. 
When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the
a.
formation of ATP.
b.
reduction of NADmc029-1.jpg.
c.
restoration of the Namc029-2.jpg/Kmc029-3.jpg balance across the membrane.
d.
creation of a proton gradient.
e.
lowering of pH in the mitochondrial matrix.
 

 30. 
Where is ATP synthase located in the mitochondrion?
a.
cytosol
b.
electron transport chain
c.
outer membrane
d.
inner membrane
e.
mitochondrial matrix
 

 31. 
Which of the following produces the most ATP when glucose (mc031-1.jpg) is completely oxidized to carbon dioxide (mc031-2.jpg) and water?
a.
glycolysis
b.
fermentation
c.
oxidation of pyruvate to acetyl CoA
d.
citric acid cycle
e.
oxidative phosphorylation (chemiosmosis)
 

 32. 
Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (mc032-1.jpg) in cellular respiration?
a.
2
b.
4
c.
15
d.
38
e.
76
 

 33. 
In liver cells, the inner mitochondrial membranes are about 5 X the area of the outer mitochondrial membranes, and about 17 X that of the cell's plasma membrane. What purpose must this serve?
a.
It allows for increased rate of glycolysis.
b.
It allows for increased rate of the citric acid cycle.
c.
It increases the surface for oxidative phosphoryation.
d.
It increases the surface for substrate-level phosphorylation.
e.
It allows the liver cell to have fewer mitochondria.
 

 34. 
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is
a.
the oxidation of glucose and other organic compounds.
b.
the flow of electrons down the electron transport chain.
c.
the affinity of oxygen for electrons.
d.
the Hmc034-1.jpg concentration gradient across the inner mitochondrial membrane.
e.
the transfer of phosphate to ADP.
 

 35. 
Most mc035-1.jpg from catabolism is released during
a.
glycolysis.
b.
the citric acid cycle.
c.
lactate fermentation.
d.
electron transport.
e.
oxidative phosphorylation.
 

Short Answer
 
 
Refer to Figure 9.1 to answer the following questions.

Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

nar001-1.jpg

Figure 9.1
 

 36. 
Which step shows a split of one molecule into two smaller molecules?
 

 37. 
In which step is an inorganic phosphate added to the reactant?
 

 38. 
In which reaction does an intermediate pathway become oxidized?
 

 39. 
Which step involves an endergonic reaction?
 

 40. 
Which step consists of a phosphorylation reaction in which ATP is the phosphate source?
 



 
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