Cell Respiration:
Homework Packet
Name:_______________________
Completion:
1. A calorie is a unit of _______________________________________________________________________________
2. A Calorie is also referred to as a _____________________________________________________________________
3. Cells use the energy stored in chemical bonds of foods to produce compounds that directly power the cell’s activities,
such as ____________________________________________________________________________________________
4. The equation that summarizes cellular respiration, using chemical formulas, is________________________________
5. Cellular respiration begins with a pathway called____________________________ which takes place in the of the cell
6. At the end of glycolysis, about ______________percent of the chemical energy is locked in the bonds of the molecule
7. Cellular respiration continues in the ___________________________of the cell with the and electron transport chain
8. The pathways of cellular respiration that require oxygen are said to be_______________________________ Pathways
that do not require oxygen are said to be_________________________________________________________________
9. What is the first stage of cellular respiration? ___________________________________________________________
10. What is the second stage of cellular respiration?________________________________________________________
11. What is the third stage of cellular respiration?__________________________________________________________
12. How many ATP molecules can the cell produce from a single molecule of glucose through glycolysis?_____________
13. If there is no oxygen in cells, the products of glycolysis enter ____________________________________ pathways
that yield no additional ___________________________.
14. Fermentation is ___________________________________________________________ because no oxygen is used.
15. If oxygen is present in cells, the glycolysis products enter the ____________________________ respiration pathway
16. What simple sugar starts glycolysis?_________________________________________________________________
17. In glycolysis, glucose is broken into 2 molecules of ____________________________________________ acid in the
___________________________________________________________ of the cell.
18. In which part of the cell does fermentation occur? Is oxygen involved?_____________________________________
19. Name the 2 types of fermentation.______________________________________________ acid fermentation helps
make cheese & yogurt and also occurs in __________________________________________ cells during heavy exercise.
20. What effect does lactic acid have on muscle cells?______________________________________________________
21. Yeasts carry on what type of fermentation?____________________________________________________________
22. What alcohol is made in alcoholic fermentation?_______________________________________________________
23. The first acid produced in the Krebs cycle is _______________________________________________________ acid
24. Two energy carriers are reduced in the Krebs cycle; _______________________________________becomes NADH
and ________________________________________ becomes FADH.
25. Is ATP made in the Krebs cycle?_____________________________________________________________________
26. What gas is a waste product produced in the Krebs cycle?________________________________________________
27. The __________________________________________________________ is the second part of aerobic respiration.
28. Where does the Electron Transport System take place in eukaryotic cells? __________________________________
29. __________________________________________________ is made in the Electron Transport System when NADH
and FADH2 release ___________________________________________________ ions.
30. What are the 3 phases of the cellular respiration process? ________________________________________________
__________________________________________________________________________________________________
31. Where in the cell does the glycolysis part of cellular respiration occur?______________________________________
32. Where in the cell does the Krebs (Citric Acid) cycle part of cellular respiration occur?___________________________
33. Where in the cell does the electron transport part of cellular respiration occur?_______________________________
34. How many ATP (net) are made in the glycolysis part of cellular respiration?__________________________________
35. How many ATP are made in the Kreb’s cycle part of cellular respiration?____________________________________
36. How many ATP are made in the electron transport part of cellular respiration?_______________________________
37. In which phase of cellular respiration is carbon dioxide made?____________________________________________
38. In which phase of cellular respiration is water made? ___________________________________________________
39. What is the overall reaction for fermentation in yeast?___________________________________________________
40. What is the overall reaction for lactic acid fermentation?________________________________________________
41. Each FADH can generate how many ATP’s of energy?____________________________________________________
42. Each NADH can generate how many ATP’s of energy?____________________________________________________
43. What are the two metabolic pathways?______________________________________________________________
__________________________________________________________________________________________________
44. Cellular respiration begins with a pathway called_______________________________________________________
45. Because fermentation does not require oxygen, it is said to be_____________________________________________
46. Because the final stages of cellular respiration require oxygen, they are said to be_____________________________
47. True or False? Hydrogen serves as the final electron acceptor of the electron transport chain. __________________
48. How many net ATP molecules are formed during cellular respiration?______________________________________
Labeling:
MULTIPLE CHOICE:
49. Organic compounds that can be made from the products of the Calvin cycle include
a. only carbohydrates.
b. only amino acids.
c. only lipids.
d. carbohydrates, amino acids, and lipids.
50. Glycolysis takes place
a. in the cytosol.
b. in the mitochondria.
c. only if oxygen is present.
d. only if oxygen is absent
51. During glycolysis, glucose is
a. produced from two molecules of pyruvic acid.
b. converted into two molecules of ATP.
c. partially broken down and some of its stored energy is released.
d. partially broken down and its stored energy is increased.
52. Both lactic-acid fermentation and alcoholic fermentation produce
a. a two-carbon molecule from a six-carbon molecule.
b. CO2 from a three-carbon molecule.
c. ATP from ADP and phosphate.
d. NAD1 from NADH and H1.
53. The efficiency of glycolysis is approximately
a. 0.35%.
b. 3.5%.
c. 35%.
d. 350%.
54. The anaerobic pathways provide enough energy to meet all of the energy needs of
a. all organisms.
b. all unicellular and most multicellular organisms.
c. many unicellular and some multicellular organisms.
d. no organisms.
55. The Krebs cycle
a. breaks down a two-carbon molecule into two molecules of CO2.
b. produces a six-carbon molecule from six molecules of CO2.
c. produces NAD1 from NADH and H1.
d. generates most of the ATP produced in aerobic respiration.
56. Fermentation in animal cells produces
a. glucose and carbon dioxide.
b. alcohol and ATP.
c. lactic acid and ATP.
d. lactic acid and carbon dioxide.
57. The electron transport chain of aerobic respiration
a. generates O2 from H2O.
b. produces NADH by chemiosmosis.
c. pumps electrons into the mitochondrial matrix.
d. pumps protons into the space between the inner and outer mitochondrial membranes.
58. The maximum efficiency of aerobic respiration is approximately
a. 0.66%.
b. 6.6%.
c. 66%.
d. 660%.
59. Before the energy in food can be used by a cell, it must first be transferred to molecules of
a. proteins. c. DNA.
b. carbohydrates. d. ATP.
c. produces NAD1 from NADH and H1.
d. generates most of the ATP produced in aerobic respiration.
60. Oxygen is used to break down food molecules and release energy in a process called
a. photosynthesis.
c. cellular respiration.
b. cytokinesis.
d. fermentation.
61. Respiration means
a. “within the cell.”
c. “made by light.”
62. A product of cellular respiration is
a. oxygen.
c. carbon dioxide.
b. water.
b. “outside the cell.”
d. “breathing.
d. Both (b) and (c).
63. Most of the energy released when food is broken down during cellular respiration is in the form of
a. heat.
c. sound.
b. light.
d. chemical.
64. Cellular respiration takes place in a eukaryotic cell’s
a. nucleus.
c. endoplasmic reticulum.
b. mitochondria.
d. Golgi complex.
65. The burning sensation you feel in your muscles after running a long distance is due to the effects of
a. active transport.
c. cellular respiration.
b. photosynthesis.
d. fermentation.
66. During fermentation, yeast cells make
a. carbon dioxide and alcohol.
c. lactic acid and ATP.
b. glucose and carbon dioxide.
d. lactic acid and carbon dioxide.
67. Organisms that are able to use basic energy sources, such as sunlight, to make energy-containing organic molecules
from inorganic raw materials are called
a. autotrophs.
b. heterotrophs.
c. aerobic.
d. anaerobic.
68. Cellular respiration processes that do not use molecular oxygen are called
a. heterotrophic.
b. anaerobic.
c. aerobic.
d. anabolic.
69. The chemical activities that remove electrons from glucose result in the glucose being
a. reduced.
b. oxidized.
c. phosphorylated.
d. hydrolysed.
70. Anaerobic pathways that oxidize glucose to generate ATP energy by using an organic molecule as the ultimate
hydrogen acceptor are called
a. fermentation.
b. reduction.
c. Krebs.
d. electron pumps.
71. The positively charged hydrogen ions that are released from the glucose during cellular respiration eventually
combine with _____ ion to form _____.
a. another hydrogen, a gas
b. a carbon, carbon dioxide
c. an oxygen, water
d. a pyruvic acid, lactic acid
72. The Krebs cycle and ETS are biochemical pathways performed in which eukaryotic organelle?
a. nucleus
b. ribosome
c. chloroplast
d. mitochondria
73. When living cells break down the bonds holding molecules together, energy is
a. stored as ADP.
c. released as heat.
b. stored as ATP.
d. changed into glucose
74. In a complete accounting of all the ATPs produced in aerobic cellular respiration, there are a total of _____ ATPs:
_____ from the ETS, _____ from glycolysis, and _____ from the Krebs cycle.
a. 36, 32, 2, 2
b. 38, 34, 2, 2
c. 36, 30, 2, 4
d. 38, 30, 4, 4
75. When skeletal muscle cells function anaerobically, they accumulate the compound _____, which causes muscle
soreness.
a. pyruvic acid
b. malic acid
c. carbon dioxide
d. lactic acid
76. Each molecule of fat can release _____ of ATP, compared with a molecule of glucose.
a. smaller amounts
b. the same amount
c. larger amounts
d. only twice the amount
77. Cellular respiration is the
a. production of organic compounds from inorganic compounds
b. break down of carbohydrates into their monomers of polysaccharides
c. continual cycle between dehydration synthesis and hydrolysis
d. conversion of organic compounds into a form of chemical energy the body can use
e. production on glucose molecules through the stimulation of light energy
78. The equation above summarizes the process known as
a. photosynthesis.
c. fermentation.
b. protein breakdown.
d. cellular respiration.
79. Energy is released from ATP when the bond is broken between
a. two phosphate groups
c. ribose and a phosphate group
b. adenine and ribose
d. adenine and a phosphate group
80. The molecule referred to as “molecule A” in the equation above is
a. NADPH.
c. NADH
b. ATP.
. ADP
81. In cellular respiration, the most energy is transferred during
a. glycolysis.
c. the Krebs cycle.
b. lactic acid fermentation.
d. the electron transport chain
82. Electrons are carried to the electron transport chain by
a. ATP and NADH.
c. ATP and NAD+.
b. FADH2 and NADH.
83. Glycolysis begins with glucose and produces
a. starch`
c. acetyl CoA
b. lactic acid
d. NAD+ and ATP.
d. pyruvic acid
84. What happens to electrons as they are transported along the electron transport chain and the H ion breaks off?
a. They lose energy.
c. They are moved out of the cell
b. They gain energy.
d. They combine with O2 and protons to form water.
85. Cellular respiration takes place in two stages:
a. glycolysis and fermentation.
b. Stage 1 and Stage 2 of photosynthesis.
c. glycolysis, then aerobic respiration.
d. anaerobic respiration, then glycolysis.
86. Which of the following is not formed during the Krebs cycle?
a. CO2
b. NADH
c. FADH2
d. Lactic Acid
87. Which of the following is not part of cellular respiration?
a. electron transport
c. glycolysis
b. the Krebs cycle
88. Glycolysis takes place
a. in the cytoplasm c. only if oxygen is present
d. the Calvin cycle
b. in the mitochondria d. only if oxygen is absent
89. Which of the following statements correctly describe(s) catabolic pathways?
a. They do not depend on enzymes.
b. They consume energy to build molecules.
c. They release energy as they degrade molecules.
d. They lead to the synthesis of catabolic compounds.
e. both A and B
90. Yeast produce alcohol and CO2 in the process of
a. lactic acid fermentation
c. alcoholic fermentation
b. aerobic respiration
91. In cellular respiration, the most energy is created in which step?
a. glycolysis c. Krebs cycle
b. electron transport chain d. fermentation
d. glycolysis
92. Both lactic acid and alcoholic fermentation produce
a. a 2-carbon molecule from a 6-carbon molecule
b. CO2 from a three-carbon molecule
c. ATP from ADP and phosphate
d. NAD+ from NADH and H+
93. The process shown in the equation above begins in the cytoplasm of a cell and ends in the
a. cytoplasm.
c. mitochondria.
b. endoplasmic reticulum
d. chloroplast.
94. Some friends are trying to make wine in their basement. They’ve added yeast to sweet grape juice mixture and
have allowed the yeast to grow. After several days they find that the sugar levels in the grape juice have dropped,
but there’s no alcohol in the mixture. The most likely explanation is that:
a. The mixture needs more sugar; yeasts need a lot of energy before they can begin to produce alcohol
b. The mixture needs more oxygen; yeast need oxygen to break down sugar and get enough energy to produce alcohol
c. The mixture needs less oxygen; yeast only produce alcohol in the absence of oxygen
d. The mixture needs less sugar; high sugar concentrations stimulate cellular respiration, and alcohol is not a by-product
of cellular respiration
95. Alcoholic fermentation is basically
a. an extension of glycolysis in the absence of oxygen
b. replacing glycolysis with the photosystem II stage
c. aerobic respiration in areas of high carbon dioxide concentration
d. cellular respiration without the Krebs cycle
e. the production of glucose in the absence of oxygen
96. Various molecules act as electron acceptors during cellular respiration. Which of the following is NOT an electron
acceptor at sometime during the processes?
a. O2
b. CO2
c. NAD+
d. FAD
Short Answer Questions:
97. Why can glycolysis supply energy to cells when oxygen is not available?
98. What happens after glycolysis?
99. How does lactic acid fermentation work?
100. What is alcoholic fermentation?
101. What happens to the small amount of alcohol produced in alcoholic fermentation during the baking of bread?
102. What happens to pyruvic acid during the Krebs cycle?
103. How does the location of the electron transport chain differ in eukaryotes and prokaryotes?
104. Where does the electron transport chain get the high-energy electrons that are passed down the chain?
105. What causes the H+ ions in the intermembrane space to move through the channels in the membrane and out into
the matrix?
106. Why is more ATP generated from glucose in the presence of oxygen?
107. What happens to the energy of glucose that is not used to make ATP molecules?
108. What are the final waste products of cellular respiration?
109. How does ATP drive endergonic reactions? How does ATP function in “coupled reactions”?
110. What is chemiosmosis and how is it generated?
111. Explain why respiration is considered exergonic.
112. Where in the cell does the glycolysis part of cellular respiration occur? Why?
113. Where in the cell does the Krebs (Citric Acid) cycle part of cellular respiration occur? Why?
114. Where in the cell does the electron transport part of cellular respiration occur? Why?
115. In glycolysis, what carbon compound is broken down? What carbon compound is the end product?
116. In glycolysis, what is the ratio of glucose molecules to the net number of ATP molecules at the end of the process?
117. Where does the breakdown of pyruvic acid occur?
118. What is the end product of the breakdown of pyruvic acid?
119. How is the breakdown of pyruvic acid related to the citric acid cycle?
120. As citric acid breaks down, what substance is released?
121. ln what industry is alcoholic fermentation important?
122. What does the buildup of lactic acid cause?
123. The energy carrier NAD+ is reduced to what substance?
124. Which part of aerobic respiration makes most of the ATP (cell’s energy)?
125. Where does aerobic respiration take place in prokaryotes?
126. Where do these reactions take place in eukaryotes?
127. What is the mitochondrial matrix & what product of glycolysis diffuses into this matrix?
128. What is found inside the mitochondrial matrix to help catalyze the reactions of the Krebs cycle?
129. What is acetyl CoA & to what does it combine?
Critical Thinking:
130. Carbon monoxide (CO), the poision cyanide, and the pesticide Rotenone all act to block electron transport. What
effect would they have on ATP production?
131. The former diet drug dinitrophenol (DNP) makes the membrane of the mitochondrian leaky to hydrogen ions.
What effect would this have on ATP production?
132. Why is glycolysis thought to be one of the earliest of all biochemical processes to have evolved?
133. How is the structure of a mitochondrion well adapted for the activities it carries out?
134. Why is alcohol made in sealed containers? What would you expect to happen if the process was open to air?