AP biology unit 3 test answer key Cellular Energetics Exam Complete Study Guide With Solution
AP biology unit 3 test answer key Cellular Energetics.pdf
Page 1 of 20 /2026 AP biology unit 3 test answer key Cellular Energetics.pdf
,AP biology unit 3 test answer key Cellular Energetics Exam Complete Study Guide With Solution
AP biology unit 3 test answer key Cellular Energetics.pdf
BIOLOGY
SECTION I
Time- 45 minutes
Directions: Each of the questions or incomplete statements below is followed by four suggested answers or
completions. Select the one that is best in each case and then enter the letter in the corresponding space on the
answer sheet.
1.
An organism is introduced to an aquarium ecosystem. The changes in carbon dioxide and oxygen gases in the
aquarium are shown in the graph after the introduction of the new organism. Which statement supports the data
shown in the graph?
a) The organism died, and decomposition is occurring in the aquarium.
b) The organism is performing cellular respiration only.
c) The organism is producing the majority of its ATP from fermentation.
d) The organism is capable of performing photosynthesis.
2. An autotrophic cell undergoing the light-dependent reactions of photosynthesis was observed to release 18-O 2, a
heavy isotope of 16-O2.
Which conclusion is most logical based on this observation?
a) The autotrophic organism had been supplied with water containing a heavy isotope of
oxygen.
b) The autotrophic organism had been supplied with carbon dioxide containing a heavy
isotope of oxygen.
c) The autotrophic organism had been supplied with glucose containing a heavy isotope of
oxygen.
d) The autotrophic organism had been supplied with nitrogen dioxide containing a heavy
isotope of oxygen.
3. Which of the following explains how enzymes affect chemical reactions?
a) Enzymes allow the reactions to occur at higher temperatures with greater kinetic energy.
b) Enzymes increase the Vmax, or maximal rate of the reaction.
c) Enzymes donate energy to the reactions, allowing nonspontaneous reaction to proceed
forward.
d) Enzymes lower activation energy which speeds up the conversion of reactants to products.
Page 2 of 20 /2026 AP biology unit 3 test answer key Cellular Energetics.pdf
, AP biology unit 3 test answer key Cellular Energetics Exam Complete Study Guide With Solution
AP biology unit 3 test answer key Cellular Energetics.pdf
4. Molecule Y is an inhibitor to the catalytic enzyme modeled below, causing a conformational change occurs in the
enzyme. Which of the following accurately describes the role of Inhibitor Y?
a) Inhibitor Y competes with substrates for binding in the active site and functions as a
competitive inhibitor.
b) Inhibitor Y binds allosterically and functions as a competitive inhibitor.
c) Inhibitor Y competes with substrates for binding in the active site and functions as a
noncompetitive inhibitor.
d) Inhibitor Y binds allosterically and functions as a noncompetitive inhibitor.
5. The Second Law of Thermodynamics states that entropy, or disorder, is constantly increasing in the universe for
spontaneous processes. Which statement explains how organisms appear as very ordered states of organization?
a) The Second Law of Thermodynamics is not applicable to biological life.
b) Energy is created by organisms but not destroyed.
c) Catabolic reactions are always equal and opposite of anabolic reactions.
d) Organisms increase entropy through the dissipation of heat and waste as products of their
metabolism.
Page 3 of 20 /2026 AP biology unit 3 test answer key Cellular Energetics.pdf
AP biology unit 3 test answer key Cellular Energetics.pdf
Page 1 of 20 /2026 AP biology unit 3 test answer key Cellular Energetics.pdf
,AP biology unit 3 test answer key Cellular Energetics Exam Complete Study Guide With Solution
AP biology unit 3 test answer key Cellular Energetics.pdf
BIOLOGY
SECTION I
Time- 45 minutes
Directions: Each of the questions or incomplete statements below is followed by four suggested answers or
completions. Select the one that is best in each case and then enter the letter in the corresponding space on the
answer sheet.
1.
An organism is introduced to an aquarium ecosystem. The changes in carbon dioxide and oxygen gases in the
aquarium are shown in the graph after the introduction of the new organism. Which statement supports the data
shown in the graph?
a) The organism died, and decomposition is occurring in the aquarium.
b) The organism is performing cellular respiration only.
c) The organism is producing the majority of its ATP from fermentation.
d) The organism is capable of performing photosynthesis.
2. An autotrophic cell undergoing the light-dependent reactions of photosynthesis was observed to release 18-O 2, a
heavy isotope of 16-O2.
Which conclusion is most logical based on this observation?
a) The autotrophic organism had been supplied with water containing a heavy isotope of
oxygen.
b) The autotrophic organism had been supplied with carbon dioxide containing a heavy
isotope of oxygen.
c) The autotrophic organism had been supplied with glucose containing a heavy isotope of
oxygen.
d) The autotrophic organism had been supplied with nitrogen dioxide containing a heavy
isotope of oxygen.
3. Which of the following explains how enzymes affect chemical reactions?
a) Enzymes allow the reactions to occur at higher temperatures with greater kinetic energy.
b) Enzymes increase the Vmax, or maximal rate of the reaction.
c) Enzymes donate energy to the reactions, allowing nonspontaneous reaction to proceed
forward.
d) Enzymes lower activation energy which speeds up the conversion of reactants to products.
Page 2 of 20 /2026 AP biology unit 3 test answer key Cellular Energetics.pdf
, AP biology unit 3 test answer key Cellular Energetics Exam Complete Study Guide With Solution
AP biology unit 3 test answer key Cellular Energetics.pdf
4. Molecule Y is an inhibitor to the catalytic enzyme modeled below, causing a conformational change occurs in the
enzyme. Which of the following accurately describes the role of Inhibitor Y?
a) Inhibitor Y competes with substrates for binding in the active site and functions as a
competitive inhibitor.
b) Inhibitor Y binds allosterically and functions as a competitive inhibitor.
c) Inhibitor Y competes with substrates for binding in the active site and functions as a
noncompetitive inhibitor.
d) Inhibitor Y binds allosterically and functions as a noncompetitive inhibitor.
5. The Second Law of Thermodynamics states that entropy, or disorder, is constantly increasing in the universe for
spontaneous processes. Which statement explains how organisms appear as very ordered states of organization?
a) The Second Law of Thermodynamics is not applicable to biological life.
b) Energy is created by organisms but not destroyed.
c) Catabolic reactions are always equal and opposite of anabolic reactions.
d) Organisms increase entropy through the dissipation of heat and waste as products of their
metabolism.
Page 3 of 20 /2026 AP biology unit 3 test answer key Cellular Energetics.pdf
