Name: 
 

Photosynthesis & Cellular Respiration


Modified True/False
Indicate whether the statement is true or false.  If false, change the identified word or phrase to make the statement true.
 

 1. 
All organisms need energy to carry out life processes. _________________________
 

 2. 
Homeostasis is the process by which plants use sunlight to make organic compounds from carbon dioxide and water. _________________________
 

 3. 
Autotrophs make inorganic compounds that serve as food for them and for almost all of the other organisms on Earth. _________________________
 

 4. 
Photosynthesis is a process that takes place in autotrophs. _________________________
 

 5. 
Photosynthesis involves using energy to build organic molecules and breaking down organic molecules in which energy is stored. _________________________
 

 6. 
Photosynthesis converts stable carbon dioxide molecules into oxygen, a less stable carbon compound. _________________________
 

 7. 
Through the process of cellular respiration, cells make carbon in glucose into stable carbon dioxide and produce energy. _________________________
 

 8. 
ATP is a portable form of energy “currency” inside cells. _________________________
 

 9. 
In cells, chemical energy is gradually released in a series of chemical compounds that are assisted by enzymes. _________________________
 

 10. 
The major light-absorbing pigment in plant photosynthesis is carotenoid. _________________________
 

 11. 
The thylakoid membrane is folded in a way that produces flat, disc-like sacs called stroma. _________________________
 

 12. 
Plant cells use light energy to make ATP and NADPH. _________________________
 

 13. 
Plants get electrons to replace the excited electrons that leave chlorophyll molecules by splitting water molecules. _________________________
 

 14. 
The final stage of photosynthesis during which sugar molecules are produced is light dependent. _________________________
 

 15. 
The reactions that “fix” carbon dioxide are sometimes called dark reactions. _________________________
 

 16. 
Most of the three-carbon sugars formed during the Calvin cycle are used to regenerate the five-carbon compound that began the cycle. _________________________
 

 17. 
Carbon dioxide concentration is one of the environmental factors that affect photosynthesis. _________________________
 

 18. 
Increasing light intensity increases the rate of photosynthesis only until all the oxygen molecules in chloroplasts are being used. _________________________
 

 19. 
Glycolysis breaks down glucose into two pyruvates. _________________________
 

 20. 
Glycolysis occurs during the second stage of cellular respiration. _________________________
 

 21. 
Glycolysis is an aerobic process. _________________________
 

 22. 
During aerobic respiration, the breakdown of a molecule of glucose yields a net of up to two molecules of ATP. _________________________
 

 23. 
The first stage of aerobic respiration is a series of biochemical reactions called the Calvin cycle. _________________________
 

 24. 
Fermentation takes place in absence of carbon dioxide. _________________________
 

 25. 
Lactic acid fermentation is an anaerobic process. _________________________
 

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

 26. 
Most of the energy used by life on Earth comes from the
a.
sun.
c.
moon.
b.
 rotation of Earth.
d.
 weather.
 

 27. 
Organisms that are not autotrophs
a.
get energy from inorganic molecules.
b.
 can survive without energy.
c.
 must consume other organisms to get energy.
d.
 get energy from sunlight.
 

 28. 
Light energy is converted to chemical energy through the process of
a.
cellular respiration.
c.
photosynthesis.
b.
 fermentation.
d.
 glycolysis.
 

 29. 
Which of the following organisms do not carry out photosynthesis?
a.
plants
c.
certain prokaryotes
b.
 algae
d.
 animals
 

 30. 
The carbon cycle makes carbon compounds continuously available in an ecosystem and delivers
a.
light energy to autotrophs.
b.
 water to all organisms.
c.
 carbon dioxide to animals within the ecosystem.
d.
 chemical energy to organisms within the ecosystem.
 

 31. 
Which of the following statements about glucose is correct?
a.
Glucose is a less stable carbon compound than carbon dioxide is.
b.
 Glucose is a more stable carbon compound than carbon dioxide is.
c.
 Glucose is produced during cellular respiration.
d.
Glucose is not a carbon compound.
 

 32. 
ATP is composed of a nitrogenous base, a sugar, and
a.
one phosphate group.
c.
three phosphate groups.
b.
 two phosphate groups.
d.
 four phosphate groups.
 

 33. 
How many carbon dioxide molecules are produced during the cellular respiration of two glucose molecules?
a.
two
c.
six
b.
 four
d.
 twelve
 

 34. 
chloroplasts : photosynthesis ::
a.
mitochondria : cellular respiration
c.
 metabolism : carbon
b.
solar energy : cellular respiration
d.
 oxygen : carbon dioxide
 

 35. 
photosynthesis : oxygen ::
a.
oxygen : carbon dioxide
c.
 cellular respiration : oxygen
b.
cellular respiration : carbon dioxide
d.
 cellular respiration : enzymes
 

 36. 
When cells break down food molecules, energy is
a.
released quickly.
b.
 released entirely as body heat into the environment.
c.
stored temporarily in ATP molecules.
d.
 stored permanently in ATP molecules.
 

 37. 
ATP is called a cell’s energy “currency” because
a.
ATP catalyzes all metabolic reactions.
b.
 ATP allows one organelle to be exchanged for another between cells.
c.
 glucose is made of ATP.
d.
 ATP can be “made” in one place and “spent” or used in another.
 

 38. 
When a phosphate group is removed from an ATP molecule,
a.
a substantial amount of energy is released.
b.
 an enzyme is formed.
c.
energy is stored.
d.
 a substantial amount of energy is used.
 

 39. 
An enzyme that catalyzes the synthesis of ATP is
a.
ATP synthase.
c.
glucose synthase.
b.
 ADP synthase.
d.
 phosphate synthase.
 

 40. 
The series of molecules that cause protons to build up on one side of a membrane is a(n)
a.
ATP synthase.
c.
ADP.
b.
 NADH.
d.
 electron transport chain.
 

 41. 
The space inside the inner membrane of a chloroplast is called the
a.
thylakoid.
c.
pigment.
b.
 reaction center.
d.
 stroma.
 

 42. 
When electrons of a chlorophyll molecule are raised to a higher energy level, they
a.
cause the plant to appear green.
b.
 form a glucose bond.
c.
 are transferred to an electron carrier.
d.
 are converted to carotenoids.
 

 43. 
Chlorophyll is green because
a.
it absorbs green wavelengths of light.
b.
 it absorbs blue and yellow wavelengths, which make green.
c.
it reflects green wavelengths of light.
d.
 of an optical illusion caused by transmitted light.
 

 44. 
eye pigments : sight ::
a.
chlorophyll : photosynthesis
c.
 carotenoids : cellular respiration
b.
photosynthesis : plants
d.
protons : electrons
 

 45. 
The major atmospheric by-product of photosynthesis is
a.
nitrogen.
c.
water.
b.
 carbon dioxide.
d.
 oxygen.
 

 46. 
Because of photosynthesis,
a.
the atmosphere is rich in oxygen gas.
b.
 animals can get energy directly from the sun.
c.
plants produce carbon dioxide.
d.
 water is constantly being produced.
 

 47. 
Which of the following enables plants to convert light energy to chemical energy?
a.
the sodium-potassium pump
c.
 sugar channels
b.
 coupled channels
d.
 hydrogen ion pumps
 

 48. 
The source of oxygen produced during photosynthesis is
a.
carbon dioxide.
c.
the air.
b.
 water.
d.
 glucose.
 

 49. 
While one type of electron transport chain of photosynthesis is used to form molecules of ATP, a second electron transport chain is used
a.
to form molecules of NADPH.
b.
 to move molecules to another ion pump.
c.
to produce water.
d.
 as a fuel for forming another chlorophyll molecule.
 

 50. 
Hydrogen ion pumps found in the thylakoid membranes are directly responsible for
a.
moving hydrogen ions out of the thylakoid.
b.
 providing the energy to produce ATP molecules.
c.
 producing NADP+.
d.
 generating glucose molecules.
 

 51. 
NADPH is important in photosynthesis because it
a.
becomes oxidized to form NADP.
b.
 is needed to form chlorophyll and carotenoids.
c.
provides additional oxygen atoms from the breakdown of water.
d.
 provides high-energy electrons needed to store energy in organic molecules.
 

 52. 
At a hydrogen ion pump of the thylakoid membrane,
a.
electrons are accepted by glucose.
b.
 electrons are pushed out of the thylakoid.
c.
energy from electrons is used to make ATP.
d.
 the thylakoid bursts, releasing energy.
 

 53. 
light energy : excite electrons ::
a.
metabolism : autotroph
b.
 carbon : electron
c.
 ATP and NADPH : carbon dioxide fixation
d.
 energy : food
 

 54. 
Products of the light reactions of photosynthesis that are required by the dark reactions are
a.
oxygen and ATP.
c.
ATP and NADPH.
b.
 water and oxygen.
d.
 oxygen and NADPH.
 

 55. 
Which of the following is not true about the dark reactions of photosynthesis?
a.
require ATP and NADPH
c.
generate sugars
b.
 are light-independent
d.
 use water as an electron source
 

 56. 
The energy used in the Calvin cycle for the production of sugar molecules comes from
a.
ATP only.
c.
ATP and NADPH.
b.
 the Krebs cycle.
d.
 carbon dioxide.
 

 57. 
Carbon dioxide is converted into organic compounds in the
a.
the Calvin cycle.
c.
the electron transport chain.
b.
 the Krebs cycle.
d.
mitochondria.
 

 58. 
During the final stage of photosynthesis, sugars are produced from
a.
oxygen.
c.
water.
b.
 sunlight.
d.
 carbon dioxide.
 

 59. 
As light intensity increases, the rate of photosynthesis
a.
increases indefinitely.
b.
 decreases indefinitely.
c.
 increases until the light saturation point is reached.
d.
 decreases until the light saturation point is reached.
 

 60. 
Low temperatures may cause photosynthesis to occur
a.
more quickly.
c.
at a constant rate.
b.
 more slowly.
d.
 only in sunlight.
 

 61. 
Which of the following environmental factors does not affect the rate of photosynthesis?
a.
oxygen concentration
c.
light intensity
b.
 carbon dioxide concentration
d.
temperature
 
 
nar001-1.jpg
 

 62. 
Refer to the illustration above. Graph A demonstrates that the rate of photosynthesis
a.
decreases in response to increasing light intensity.
b.
 increases indefinitely in response to increasing light intensity.
c.
 increases in response to increasing light intensity, but only to a certain point.
d.
 is unaffected by changes in light intensity.
 

 63. 
Refer to the illustration above. Taken together, these graphs demonstrate that
a.
photosynthesis is independent of environmental influences.
b.
 increases in light intensity cause increases in temperature.
c.
 as the rate of photosynthesis increases, the temperature of a plant eventually decreases.
d.
 the rate of photosynthesis is affected by changes in the environment.
 

 64. 
When glycolysis occurs,
a.
a molecule of glucose is split.
c.
 photosynthesis begins.
b.
a molecule of glucose is formed.
d.
 pyruvates are combined.
 

 65. 
The process of cellular respiration
a.
is performed only by organisms that are incapable of photosynthesis.
b.
breaks down food molecules to release stored energy.
c.
 occurs before plants are able to continue photosynthesis.
d.
 occurs only in animals.
 

 66. 
What is the net gain of ATP molecules in glycolysis?
a.
1
c.
6
b.
 2
d.
 34
 

 67. 
Cellular respiration takes place in two stages:
a.
glycolysis, then photosynthesis.
b.
 electron transport chain, then fermentation.
c.
glycolysis, then aerobic respiration.
d.
 fermentation, then glycolysis
 

 68. 
Which of the following is not part of cellular respiration?
a.
electron transport
c.
Krebs cycle
b.
 glycolysis
d.
 Calvin cycle
 

 69. 
In aerobic respiration, a two-carbon molecule combines with a four-carbon molecule as part of
a.
glycolysis.
c.
the Krebs cycle.
b.
 carbon dioxide fixation.
d.
 the electron transport chain.
 

 70. 
The final electron acceptor in aerobic respiration is
a.
water.
c.
NADPH.
b.
 ATP.
d.
 oxygen.
 

 71. 
Water is an end product in
a.
lactic acid fermentation.
b.
 alcoholic fermentation.
c.
 the Krebs cycle.
d.
the electron transport chain in aerobic respiration.
 

 72. 
In the second stage of aerobic respiration, what happens to the electrons that have been depleted of their energy during ATP production?
a.
They combine with oxygen and hydrogen ions to form water.
b.
 They combine with oxygen to form carbon dioxide.
c.
 They build up inside the mitochondria and diffuse back to a thylakoid.
d.
 They are excited by light energy.
 

 73. 
Which of the following is not formed during the Krebs cycle?
a.
CO2
c.
NADH
b.
 FADH2
d.
 NADPH
 

 74. 
Which of the following is the best explanation for the presence of both chloroplasts and mitochondria in plant cells?
a.
In the light, plants make their own glucose, but in the dark, photosynthesis stops and mitochondria make glucose.
b.
 If plants cannot produce enough ATP in the process of photosynthesis to meet their energy needs, they can produce it in aerobic respiration.
c.
Sugars are produced in chloroplasts. These sugars can be stored and used by the mitochondria to produce ATP.
d.
 The leaves and sometimes the stems of plants contain chloroplasts, which produce ATP to meet the energy needs of these plant parts. The roots of plants contain mitochondria, which produce ATP to meet the energy needs of these plant parts.
 

 75. 
The name of the process that takes place when organic compounds are broken down in the absence of oxygen is
a.
respiration.
c.
fermentation.
b.
 oxidation.
d.
 photosynthesis.
 

 76. 
Fermentation enables glycolysis to continue under
a.
anaerobic conditions.
c.
photosynthetic conditions.
b.
 aerobic conditions.
d.
 low-light conditions.
 

 77. 
If oxygen is absent during the second stage of cellular respiration,
a.
fermentation will occur.
b.
 the Krebs cycle begins.
c.
 the electron transport chain works more efficiently.
d.
 glycolysis stops.
 

 78. 
Cells produce ATP most efficiently in the presence of
a.
water.
c.
oxygen.
b.
 carbon dioxide.
d.
 glucose.
 

 79. 
The total amount of ATP that a cell gains for each glucose molecule depends on the presence of
a.
water.
c.
oxygen.
b.
 carbon dioxide.
d.
 glucose.
 

 80. 
Which of the following processes produces the most ATP?
a.
aerobic respiration
c.
lactic acid fermentation
b.
glycolysis
d.
alcoholic fermentation
 

Completion
Complete each statement.
 

 81. 
The ultimate source of energy for all life on Earth is the ____________________.
 
 

 82. 
Energy from the sun enters living systems through ____________________ such as plants and certain prokaryotes.
 
 

 83. 
Autotrophs are organisms that use energy from ____________________ to make organic compounds.
 
 

 84. 
Animals get energy from food through the process of ____________________.
 
 

 85. 
Of the different inputs and products of photosynthesis, the most stable form of ____________________ is carbon dioxide.
 
 

 86. 
Of the inputs and outputs of cellular respiration, the less stable carbon compound is ____________________.
 
 

 87. 
Organisms extract energy stored in glucose through the process of cellular ____________________.
 
 

 88. 
____________________ is the organic molecule that is the main energy source for cell processes and is made with the energy released from the breakdown of glucose.
 
 

 89. 
____________________ is the energy “currency” of a cell.
 
 

 90. 
When a phosphate group is removed from an ATP molecule, a(n) ____________________ molecule is formed.
 
 

 91. 
When a phosphate group is removed from an ATP molecule, energy is ____________________.
 
 

 92. 
ATP synthase acts as both an enzyme and a carrier protein for ____________________ ions.
 
 

 93. 
Plant pigments that absorb primarily red and blue light are ____________________ pigments, while plant pigments that absorb blue and green light are ____________________ pigments.
 
 

 94. 
During the first stage of photosynthesis, ____________________ is absorbed by chlorophyll.
 
 

 95. 
The abundance of oxygen in Earth’s atmosphere is a result of the process of ____________________.
 
 

 96. 
The electron transport chain produces molecules that temporarily store ____________________ in the cell.
 
 

 97. 
During photosynthesis, the electron transport chains provide energy to make two molecules, ____________________ and ____________________.
 
 

 98. 
The energy lost by electrons while in the electron transport chain is used to pump ____________________ ions into the thylakoid.
 
 

 99. 
The use of carbon dioxide to make organic compounds is called carbon dioxide ____________________.
 
 

 100. 
The final stage of photosynthesis, in which sugars are produced, is called ____________________ fixation.
 
 

 101. 
Because of the enzyme-assisted chemical reactions involved in photosynthesis, photosynthesis occurs best within a certain ____________________ range.
 
 

 102. 
Three factors affecting the rate of photosynthesis are light intensity, ____________________ concentration, and temperature.
 
 

 103. 
In cellular respiration, glucose is split into two smaller molecules during a process called ____________________.
 
 

 104. 
____________________ is the anaerobic breakdown of glucose to pyruvates.
 
 

 105. 
During the first stage of cellular respiration, one six-carbon glucose molecule is converted to two three-carbon ____________________.
 
 

 106. 
Electrons that provide the energy for the production of most of a cell’s ATP are carried to the electron transport chain by ____________________ and ____________________ molecules.
 
 

 107. 
Fermentation allows for the recycling of NAD+ and production of ATP under ____________________ conditions.
 
 

 108. 
In the absence of oxygen, instead of aerobic respiration following glycolysis, glycolysis is followed by ____________________.
 
 

 109. 
During fermentation, either ethyl alcohol and carbon dioxide or ____________________ is formed.
 
 

Short Answer
 

 110. 
In what parts of organic compounds is energy stored and available for use?
 

 111. 
What energy source do most autotrophs use to make their own organic molecules?
 

 112. 
What do autotrophs need from the environment in order to carry out photosynthesis?
 

 113. 
What are organisms that are able to perform photosynthesis, such as plants, called?
 

 114. 
What form is carbon in an ecosystem after photosynthesis? After cellular respiration?
 

 115. 
What two inputs are needed for cellular respiration?
 

 116. 
What organic molecule is the main energy source for cell processes?
 

 117. 
Name the process by which cells produce energy from carbohydrates.
 

 118. 
When cells break down food molecules, what happens to the energy that was stored in the chemical bonds of the molecules?
 

 119. 
What makes the chain of three phosphate groups in ATP unstable?
 

 120. 
What enzyme catalyzes a reaction in which a phosphate group is added to a molecule of ADP? What molecule is made by this reaction?
 

 121. 
When light hits a plant, what colors of light are absorbed by chlorophyll?
 

 122. 
Name three pigments in plants.
 

 123. 
How do chlorophyll molecules replace the electrons that leave the chlorophyll?
 

 124. 
What is the source of the oxygen that plants add to the atmosphere?
 

 125. 
Compare the source of replacement electrons for the two electron transport chains in photosynthesis.
 

 126. 
How is the carrier protein that allows the diffusion of hydrogen ions into the thylakoid unusual?
 

 127. 
What is the most common method of carbon dioxide fixation?
 

 128. 
What are three environmental factors that affect the rate of photosynthesis?
 

 129. 
What is the saturation point of light in a chloroplast?
 

 130. 
How might unfavorable temperatures affect the rate of photosynthesis?
 

 131. 
Where does glycolysis take place in a cell?
 

 132. 
What are three different products of glycolysis?
 

 133. 
What is the difference between aerobic and anaerobic processes?
 

 134. 
Where does the second stage of aerobic respiration take place?
 

 135. 
During the Krebs cycle, what happens each time the six-carbon compound releases a carbon dioxide molecule?
 

 136. 
Under anaerobic conditions, what are electrons transferred to in order to recycle NAD+?
 

 137. 
What are two types of fermentation?
 

 138. 
What type of respiration must follow glycolysis to maximize ATP production?
 



 
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