AP Biology Chapter 10 Practice Test
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Are you ready for this AP biology chapter 10 practice test? Advanced Placement Biology (also known as AP Bio) is an Advanced Placement biology course and exam that is offered by the College Board in the United States. For the 2012–2013 school year, the College Board brought a new curriculum with a greater focus on "scientific practices." So, here is a quiz to test how much you know. Let's see! Best of luck!
- 1.
Organisms that can exist with light as an energy source and an inorganic form of carbon and other raw materials
- A.
Are called photoautotrophs.
- B.
Do not exist in nature.
- C.
Are called heterotrophs.
- D.
Are best classified as decomposers.
- E.
Both C and D
Correct Answer
A. Are called photoautotrophs.Explanation
Photoautotrophs are organisms that can use light as an energy source and inorganic forms of carbon and other raw materials to carry out photosynthesis. They are able to convert sunlight into chemical energy, which they use to synthesize organic compounds. This ability allows them to produce their own food and sustain themselves without relying on other organisms. Examples of photoautotrophs include plants, algae, and some bacteria.Rate this question:
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- 2.
Which type of organism obtains energy by metabolizing molecules produced by other organisms?
- A.
Autotrophs
- B.
Heterotrophs
- C.
Decomposers
- D.
B and C
- E.
A, B, and C
Correct Answer
D. B and CExplanation
Heterotrophs obtain energy by metabolizing molecules produced by other organisms, while decomposers also obtain energy by breaking down dead organic matter. Autotrophs, on the other hand, are organisms that can produce their own energy through photosynthesis or chemosynthesis. Therefore, the correct answer is B and C.Rate this question:
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- 3.
The early suggestion that the oxygen (O2) liberated from plants during photosynthesis comes from water was
- A.
First proposed by C.B. van Niel of Stanford University.
- B.
Confirmed by experiments using oxygen-18 (18O).
- C.
Made following the discovery of photorespiration because of rubisco's sensitivity to oxygen.
- D.
A and B
- E.
A, B, and C
Correct Answer
D. A and BExplanation
The correct answer is A and B. The early suggestion that the oxygen liberated from plants during photosynthesis comes from water was first proposed by C.B. van Niel of Stanford University. This suggestion was then confirmed by experiments using oxygen-18 (18O).Rate this question:
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- 4.
If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one exception is
- A.
PGA.
- B.
PGAL.
- C.
Glucose.
- D.
RuBP.
- E.
O2.
Correct Answer
E. O2.Explanation
When photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), all the compounds produced in the process should contain the 18O label, except for O2. This is because during photosynthesis, CO2 is taken in and converted into organic compounds such as PGA, PGAL, glucose, and RuBP. However, O2 is released as a byproduct of photosynthesis and does not incorporate the heavy oxygen label. Therefore, O2 is the exception among the compounds produced by the algae.Rate this question:
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- 5.
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
- A.
CO2 and glucose
- B.
H2O and O2
- C.
ADP, Pi, and NADP+
- D.
Electrons and H+
- E.
ATP and NADPH
Correct Answer
E. ATP and NADPHExplanation
ATP and NADPH are products of the light reactions of photosynthesis that are utilized in the Calvin cycle. The light reactions occur in the thylakoid membrane of the chloroplasts and involve the absorption of light energy, which is used to generate ATP and NADPH. These energy-rich molecules are then used in the Calvin cycle, which takes place in the stroma of the chloroplasts, to fuel the production of glucose. CO2 and glucose are not products of the light reactions, but rather are involved in the Calvin cycle itself. H2O and O2 are reactants in the light reactions, while ADP, Pi, and NADP+ are molecules that are regenerated during the light reactions but are not directly utilized in the Calvin cycle.Rate this question:
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- 6.
What is the primary function of the light reactions of photosynthesis?
- A.
To produce energy-rich glucose from carbon dioxide and water
- B.
To produce ATP and NADPH
- C.
To produce NADPH used in respiration
- D.
To convert light energy to the chemical energy of PGAL
- E.
To use ATP to make glucose
Correct Answer
B. To produce ATP and NADPHExplanation
The primary function of the light reactions of photosynthesis is to produce ATP and NADPH. These molecules are essential for the Calvin cycle, where they are used to convert carbon dioxide into glucose. ATP is the main energy currency of cells, providing the energy needed for various cellular processes. NADPH is a reducing agent that provides the necessary electrons for the synthesis of glucose. Therefore, the production of ATP and NADPH in the light reactions is crucial for the overall process of photosynthesis.Rate this question:
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- 7.
What are the products of the light reactions that are subsequently used by the Calvin cycle?
- A.
Oxygen and carbon dioxide
- B.
Carbon dioxide and RuBP
- C.
Water and carbon
- D.
Electrons and photons
- E.
ATP and NADPH
Correct Answer
E. ATP and NADPHExplanation
The products of the light reactions, ATP and NADPH, are subsequently used by the Calvin cycle. ATP provides the necessary energy for the Calvin cycle to convert carbon dioxide into glucose, while NADPH provides the necessary electrons for the reduction of carbon dioxide. These two products are essential for the Calvin cycle to carry out its function of carbon fixation and glucose synthesis.Rate this question:
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- 8.
Where does the Calvin cycle take place?
- A.
Stroma of the chloroplast
- B.
Thylakoid membrane
- C.
Cytoplasm surrounding the chloroplast
- D.
Chlorophyll molecule
- E.
Outer membrane of the chloroplast
Correct Answer
A. Stroma of the chloroplastExplanation
The Calvin cycle takes place in the stroma of the chloroplast. The stroma is the fluid-filled region inside the chloroplast where various metabolic reactions occur, including the Calvin cycle. In this cycle, carbon dioxide is converted into glucose using the energy from ATP and NADPH produced during the light-dependent reactions that take place in the thylakoid membrane. Therefore, the stroma provides the necessary environment for the Calvin cycle to occur and for the synthesis of glucose, an essential molecule for plant growth and metabolism.Rate this question:
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- 9.
A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are not being absorbed by this pigment?
- A.
Red and yellow
- B.
Blue and violet
- C.
Green and yellow
- D.
Blue, green, and red
- E.
Green, blue, and violet
Correct Answer
A. Red and yellowExplanation
The correct answer is red and yellow. This is because the leaves of the plant appear reddish yellow, which means that the pigment in the plant is absorbing all other wavelengths of visible light except for red and yellow. The absorbed light is used for photosynthesis, while the red and yellow light is reflected, giving the leaves their color.Rate this question:
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- 10.
During photosynthesis, visible light has enough energy to
- A.
Force electrons closer to the nucleus.
- B.
Excite electrons.
- C.
Split a water molecule into hydrogen and oxygen.
- D.
B and C only.
- E.
A, B, and C.
Correct Answer
B. Excite electrons.Explanation
During photosynthesis, visible light is absorbed by pigments in chloroplasts, such as chlorophyll. This absorbed light energy excites electrons in the pigment molecules, causing them to move to a higher energy state. These excited electrons are then used in the process of converting carbon dioxide and water into glucose and oxygen. Therefore, the correct answer is "excite electrons" as visible light has enough energy to excite electrons in the pigment molecules during photosynthesis.Rate this question:
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- 11.
This figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?
- A.
Green and yellow wavelengths inhibit the absorption of red and blue wavelengths.
- B.
Bright sunlight destroys photosynthetic pigments.
- C.
Oxygen given off during photosynthesis interferes with the absorption of light.
- D.
Other pigments absorb light in addition to chlorophyll a.
- E.
Aerobic bacteria take up oxygen which changes the measurement of the rate of photosynthesis.
Correct Answer
D. Other pigments absorb light in addition to chlorophyll a.Explanation
The absorption spectrum for chlorophyll a shows the wavelengths of light that chlorophyll a can absorb. However, the action spectrum for photosynthesis shows the wavelengths of light that are most effective in driving the process of photosynthesis. The fact that the action spectrum and absorption spectrum are different suggests that other pigments, in addition to chlorophyll a, are involved in absorbing light and driving photosynthesis. These additional pigments can absorb wavelengths of light that chlorophyll a cannot, allowing for a wider range of light to be utilized in photosynthesis.Rate this question:
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- 12.
What wavelength of light is most effective in driving photosynthesis?
- A.
420 mm
- B.
475 mm
- C.
575 mm
- D.
625 mm
- E.
730 mm
Correct Answer
A. 420 mmExplanation
The correct answer is 420 mm. This wavelength of light is most effective in driving photosynthesis because it corresponds to the peak absorption spectrum of chlorophyll, the pigment responsible for capturing light energy in plants. This means that plants are able to absorb and utilize the energy from light with a wavelength of 420 mm most efficiently for the process of photosynthesis.Rate this question:
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- 13.
In the thylakoid membranes, what is the main role of the antenna pigment molecules?
- A.
Split water and release oxygen to the reaction-center chlorophyll
- B.
Harvest photons and transfer light energy to the reaction-center chlorophyll
- C.
Synthesize ATP from ADP and Pi
- D.
Transfer electrons to ferredoxin and then NADPH
- E.
Concentrate photons within the stroma
Correct Answer
B. Harvest photons and transfer light energy to the reaction-center chlorophyllExplanation
The main role of the antenna pigment molecules in the thylakoid membranes is to harvest photons and transfer light energy to the reaction-center chlorophyll. These pigment molecules are responsible for absorbing light of various wavelengths and transferring the energy to the reaction-center chlorophyll, where it is used in the process of photosynthesis. This allows the plant to convert light energy into chemical energy, which is essential for the production of ATP and NADPH, the molecules needed for the synthesis of glucose.Rate this question:
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- 14.
The reaction-center chlorophyll of photosystem I is known as P700 because
- A.
There are 700 chlorophyll molecules in the center.
- B.
This pigment is best at absorbing light with a wavelength of 700 nm.
- C.
There are 700 photosystem I components to each chloroplast.
- D.
It absorbs 700 photons per microsecond.
- E.
The plastoquinone reflects light with a wavelength of 700 nm.
Correct Answer
B. This pigment is best at absorbing light with a wavelength of 700 nm.Explanation
The reaction-center chlorophyll of photosystem I is known as P700 because this pigment is best at absorbing light with a wavelength of 700 nm. This suggests that P700 is specifically adapted to capture light energy at this wavelength, allowing photosystem I to efficiently convert light energy into chemical energy during photosynthesis.Rate this question:
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- 15.
All of the events listed below occur in the light reactions of photosynthesis except
- A.
Oxygen is produced.
- B.
NADP+ is reduced to NADPH.
- C.
Carbon dioxide is incorporated into PGA.
- D.
ADP is phosphorylated to yield ATP.
- E.
Light is absorbed and funneled to reaction-center chlorophyll a.
Correct Answer
C. Carbon dioxide is incorporated into PGA.Explanation
In the light reactions of photosynthesis, oxygen is produced as a byproduct of the splitting of water molecules. NADP+ is reduced to NADPH, which is an important electron carrier in the process. ADP is phosphorylated to yield ATP, which is the main energy currency of the cell. Light is absorbed and funneled to reaction-center chlorophyll a, which is necessary for the initiation of photosynthesis. However, carbon dioxide is not incorporated into PGA (phosphoglycerate), a molecule that is formed during the Calvin cycle, which is the second stage of photosynthesis.Rate this question:
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- 16.
Which of the following statements about the light reactions of photosynthesis are true?
- A.
The splitting of water molecules provides a source of electrons.
- B.
Chlorophyll (and other pigments) absorb light energy, which excites electrons.
- C.
ATP is generated by photophosphorylation.
- D.
Only A and C are true.
- E.
A, B, and C are true.
Correct Answer
E. A, B, and C are true.Explanation
The correct answer is A, B, and C are true. In the light reactions of photosynthesis, water molecules are split to provide a source of electrons. Chlorophyll and other pigments absorb light energy, which excites electrons. ATP is generated by photophosphorylation, a process that uses light energy to add a phosphate group to ADP. Therefore, all three statements are true.Rate this question:
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- 17.
All of the following are directly associated with photosystem II except
- A.
Extraction of hydrogen electrons from the splitting of water.
- B.
Release of oxygen.
- C.
Harvesting of light energy by chlorophyll.
- D.
NADP+ reductase.
- E.
P680 reaction-center chlorophyll.
Correct Answer
D. NADP+ reductase.Explanation
Photosystem II is responsible for the extraction of hydrogen electrons from the splitting of water, the release of oxygen, and the harvesting of light energy by chlorophyll. NADP+ reductase, on the other hand, is associated with photosystem I, which is responsible for the transfer of electrons to NADP+ to form NADPH. Therefore, NADP+ reductase is not directly associated with photosystem II.Rate this question:
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- 18.
All of the following are directly associated with photosystem I except
- A.
Harvesting of light energy by chlorophyll.
- B.
Receiving electrons from plastocyanin.
- C.
P700 reaction-center chlorophyll.
- D.
Extraction of hydrogen electrons from the splitting of water.
- E.
Passing electrons to ferredoxin.
Correct Answer
D. Extraction of hydrogen electrons from the splitting of water.Explanation
Photosystem I (PSI) is one of the two photosystems in the process of photosynthesis. It is responsible for receiving electrons from plastocyanin and passing them to ferredoxin. Additionally, PSI contains P700 reaction-center chlorophyll, which is the primary pigment involved in absorbing light energy. However, PSI is not directly involved in the extraction of hydrogen electrons from the splitting of water, which is a process associated with photosystem II (PSII). Therefore, the correct answer is "extraction of hydrogen electrons from the splitting of water."Rate this question:
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- 19.
Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be
- A.
To determine if they have thylakoids in the chloroplasts.
- B.
To test for liberation of O2 in the light.
- C.
To test for CO2 fixation in the dark.
- D.
To do experiments to generate an action spectrum.
- E.
To test for production of either sucrose or starch.
Correct Answer
B. To test for liberation of O2 in the light.Explanation
The best way to detect the lack of photosystem II in these organisms would be to test for liberation of O2 in the light. Photosystem II is responsible for the initial step of photosynthesis, which involves the splitting of water molecules and release of oxygen. If an organism lacks photosystem II, it would not be able to produce oxygen during photosynthesis. Therefore, testing for liberation of O2 in the light would indicate the presence or absence of photosystem II in the chloroplasts of these organisms.Rate this question:
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- 20.
What are the products of noncyclic photophosphorylation?
- A.
Heat and fluorescence
- B.
ATP and P700
- C.
ATP and NADPH
- D.
ADP and NADP
- E.
P700 and P680
Correct Answer
C. ATP and NADPHExplanation
Noncyclic photophosphorylation is a process in photosynthesis where ATP and NADPH are produced. During this process, light energy is absorbed by photosystem II (P680), which excites electrons. These electrons then pass through an electron transport chain, generating ATP through chemiosmosis. The electrons are then transferred to photosystem I (P700), where they are re-energized by another photon of light. Finally, the electrons are transferred to NADP+, reducing it to NADPH. Therefore, the correct answer is ATP and NADPH.Rate this question:
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- 21.
What does cyclic electron flow in the chloroplast produce?
- A.
ATP
- B.
NADPH
- C.
Glucose
- D.
A and B
- E.
A, B, and C
Correct Answer
A. ATPExplanation
Cyclic electron flow in the chloroplast produces ATP. This process occurs when electrons from photosystem I are redirected back to the electron transport chain, instead of being transferred to NADP+ to produce NADPH. As a result, only ATP is generated through cyclic electron flow, while NADPH is not produced. Glucose is not directly produced through cyclic electron flow.Rate this question:
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- 22.
As a research scientist, you measure the amount of ATP and NADpH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADpH. Where did the extra ATP molecules come from?
- A.
Photosystem II
- B.
Photosystem I
- C.
Cyclic electron flow
- D.
Noncyclic electron flow
- E.
Chlorophyll
Correct Answer
C. Cyclic electron flowExplanation
Cyclic electron flow is the process in photosynthesis where electrons from photosystem I are cycled back to the electron transport chain instead of being transferred to NADP+ to produce NADPH. This process generates additional ATP molecules without consuming NADPH. Therefore, the extra ATP molecules in this scenario likely came from cyclic electron flow.Rate this question:
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- 23.
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?
- A.
The splitting of water
- B.
The absorption of light energy by chlorophyll
- C.
The flow of electrons from photosystem II to photosystem I
- D.
The synthesis of ATP
- E.
The reduction of NADP+
Correct Answer
D. The synthesis of ATPExplanation
If a thylakoid is punctured and the interior is no longer separated from the stroma, it will disrupt the process of the synthesis of ATP. The synthesis of ATP occurs through the process of chemiosmosis, where protons are pumped into the thylakoid lumen and then flow back through ATP synthase to generate ATP. If the thylakoid is punctured, the proton gradient will be disrupted, and ATP synthesis will be impaired. This will have the most direct effect on the synthesis of ATP compared to the other processes listed.Rate this question:
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- 24.
What does the chemiosmotic process in chloroplasts involve?
- A.
Establishment of a proton gradient
- B.
Diffusion of electrons through the thylakoid membrane
- C.
Reduction of water to produce ATP energy
- D.
Movement of water by osmosis into the thylakoid space from the stroma
- E.
Formation of glucose, using carbon dioxide, NADPH, and ATP
Correct Answer
A. Establishment of a proton gradientExplanation
The chemiosmotic process in chloroplasts involves the establishment of a proton gradient. This process occurs during photosynthesis, where light energy is converted into chemical energy in the form of ATP. The energy from light is used to pump protons across the thylakoid membrane, creating a concentration gradient. This gradient is then used to drive the synthesis of ATP through the enzyme ATP synthase. Thus, the correct answer is the establishment of a proton gradient.Rate this question:
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- 25.
Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH-8 solution. What would be likely to happen?
- A.
The isolated chloroplasts will make ATP.
- B.
The Calvin cycle will be activated.
- C.
Cyclic photophosphorylation will occur.
- D.
Only A and B will occur.
- E.
A, B, and C will occur.
Correct Answer
A. The isolated chloroplasts will make ATP.Explanation
When the interior of the thylakoids of isolated chloroplasts is made acidic and then transferred to a pH-8 solution, the proton gradient across the thylakoid membrane will be disrupted. This disruption will inhibit the production of ATP through photophosphorylation, as the proton gradient is necessary for ATP synthesis. Therefore, the chloroplasts will not be able to produce ATP in this scenario. The Calvin cycle, which is responsible for the synthesis of glucose, is also dependent on ATP and NADPH produced during photophosphorylation. Since ATP production is inhibited, the Calvin cycle will not be activated either. Therefore, only the first statement, "The isolated chloroplasts will make ATP," is correct.Rate this question:
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- 26.
In a plant cell, where are the ATP synthase complexes located?
- A.
Thylakoid membrane
- B.
Plasma membrane
- C.
Inner mitochondrial membrane
- D.
A and C
- E.
A, B, and C
Correct Answer
D. A and CExplanation
ATP synthase complexes are located in both the thylakoid membrane of chloroplasts (in plant cells) and the inner mitochondrial membrane. This is because both chloroplasts and mitochondria are involved in energy production and ATP synthesis through the process of photosynthesis and cellular respiration, respectively. The thylakoid membrane is where the light-dependent reactions of photosynthesis occur, while the inner mitochondrial membrane is where the electron transport chain and oxidative phosphorylation take place. Therefore, ATP synthase complexes are present in both these membranes to generate ATP.Rate this question:
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- 27.
In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from
- A.
The stroma to the photosystem II.
- B.
The matrix to the stroma.
- C.
The stroma to the thylakoid space.
- D.
The intermembrane space to the matrix.
- E.
ATP synthase to NADP+ reductase.
Correct Answer
C. The stroma to the thylakoid space.Explanation
In chloroplasts, chemiosmosis translocates protons from the stroma to the thylakoid space. This is because during photosynthesis, protons are pumped across the thylakoid membrane from the stroma to the thylakoid space, creating a proton gradient. This gradient is then used by ATP synthase to produce ATP, which is an important energy source for the cell. Therefore, the correct answer is the stroma to the thylakoid space.Rate this question:
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- 28.
Which of the following statements best describes the relationship between photosynthesis and respiration?
- A.
Respiration is the reversal of the biochemical pathways of photosynthesis.
- B.
Photosynthesis stores energy in complex organic molecules, while respiration releases it.
- C.
Photosynthesis occurs only in plants and respiration occurs only in animals.
- D.
ATP molecules are produced in photosynthesis and used up in respiration.
- E.
Respiration is anabolic and photosynthesis is catabolic.
Correct Answer
B. Photosynthesis stores energy in complex organic molecules, while respiration releases it.Explanation
Photosynthesis and respiration are two interconnected processes that occur in living organisms. Photosynthesis is the process by which plants convert sunlight, carbon dioxide, and water into glucose and oxygen, storing energy in the form of complex organic molecules. On the other hand, respiration is the process by which organisms break down glucose and other organic molecules to release energy in the form of ATP. Therefore, the statement that "Photosynthesis stores energy in complex organic molecules, while respiration releases it" accurately describes the relationship between these two processes.Rate this question:
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- 29.
Where is the electron transport chain found in plant cells?
- A.
Thylakoid membranes of chloroplasts
- B.
Stroma of chloroplasts
- C.
Inner membrane of mitochondria
- D.
Matrix of mitochondria
- E.
Cytoplasm
Correct Answer
A. Thylakoid membranes of chloroplastsExplanation
The electron transport chain is found in the thylakoid membranes of chloroplasts in plant cells. This is where the light-dependent reactions of photosynthesis occur. During these reactions, light energy is used to generate high-energy electrons, which are then passed through the electron transport chain in the thylakoid membranes. This process ultimately leads to the production of ATP and NADPH, which are used in the light-independent reactions of photosynthesis to convert carbon dioxide into glucose.Rate this question:
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- 30.
Of the following, what do both mitochondria and chloroplasts have in common?
- A.
Thylakoid membranes
- B.
Chemiosmosis
- C.
ATP synthase
- D.
B and C only
- E.
A, B, and C
Correct Answer
D. B and C onlyExplanation
Both mitochondria and chloroplasts have in common the presence of thylakoid membranes, which are involved in photosynthesis. Additionally, both organelles utilize chemiosmosis, a process that generates ATP by pumping protons across a membrane. ATP synthase is the enzyme responsible for the synthesis of ATP in both mitochondria and chloroplasts. Therefore, the correct answer is B and C only.Rate this question:
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- 31.
A. photosynthesis B. respiration C. both photosynthesis and respiration D. neither photosynthesis nor respiration Refer to the choices above. Indicate during which process the following occurs: reduction of oxygen which forms water
Correct Answer
B
bExplanation
During respiration, the reduction of oxygen occurs, which forms water. This process takes place in the mitochondria of cells. Oxygen is used as the final electron acceptor in the electron transport chain, and as a result, it is reduced to form water. This process is essential for the production of energy in the form of ATP. Therefore, the correct answer is respiration.Rate this question:
- 32.
A. photosynthesis B. respiration C. both photosynthesis and respiration D. neither photosynthesis nor respiration Refer to the choices above. Indicate during which process the following occurs: reduction of NADP+
Correct Answer
A
aExplanation
During photosynthesis, the reduction of NADP+ occurs. NADP+ is reduced to NADPH, which is an important molecule in the light-dependent reactions of photosynthesis. This reduction reaction involves the transfer of electrons and hydrogen ions to NADP+, converting it into NADPH. This process is essential for the production of energy-rich molecules, such as glucose, during photosynthesis.Rate this question:
- 33.
A. photosynthesis B. respiration C. both photosynthesis and respiration D. neither photosynthesis nor respiration Refer to the choices above. Indicate during which process the following occurs: the splitting of carbon dioxide to form oxygen gas and carbon compounds
Correct Answer
C
cExplanation
During both photosynthesis and respiration, the splitting of carbon dioxide occurs to form oxygen gas and carbon compounds. In photosynthesis, this process takes place in the light-dependent reactions, where carbon dioxide is split to release oxygen and combine with hydrogen to form glucose. In respiration, carbon dioxide is produced as a waste product when glucose is broken down to release energy, and the carbon dioxide can later be split to form oxygen and carbon compounds. Therefore, both photosynthesis and respiration involve the splitting of carbon dioxide to form oxygen gas and carbon compounds.Rate this question:
- 34.
A. photosynthesis B. respiration C. both photosynthesis and respiration D. neither photosynthesis nor respiration Refer to the choices above. Indicate during which process the following occurs: generation of proton gradients across membranes
Correct Answer
C
cExplanation
During both photosynthesis and respiration, the generation of proton gradients across membranes occurs. In photosynthesis, proton gradients are generated during the light-dependent reactions in the thylakoid membrane of chloroplasts. In respiration, proton gradients are generated during the electron transport chain in the inner mitochondrial membrane. Therefore, both photosynthesis and respiration involve the generation of proton gradients across membranes.Rate this question:
- 35.
Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?
- A.
The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.
- B.
The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the cycle provides water and electrons to the light reactions.
- C.
The light reactions supply the Calvin cycle with CO2 to produce sugars, and the Calvin cycle supplies the light reactions with sugars to produce ATP.
- D.
The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provides the light reactions with water to split.
- E.
There is no relationship between the light reactions and the Calvin cycle.
Correct Answer
A. The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.Explanation
The light reactions in photosynthesis convert light energy into chemical energy in the form of ATP and NADPH. These energy-rich molecules are then used in the Calvin cycle, which is the process that fixes carbon dioxide and produces sugars. In the Calvin cycle, ATP and NADPH are consumed, and ADP, Pi (inorganic phosphate), and NADP+ are produced. This creates a cyclical relationship between the light reactions and the Calvin cycle, where the light reactions provide the necessary energy molecules for the Calvin cycle, and the Calvin cycle returns the spent molecules back to the light reactions for regeneration.Rate this question:
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- 36.
Where do the enzymatic reactions of the Calvin cycle take place?
- A.
Stroma of the chloroplast
- B.
Thylakoid membranes
- C.
Outer membrane of the chloroplast
- D.
Electron transport chain
- E.
Thylakoid space
Correct Answer
A. Stroma of the chloroplastExplanation
The enzymatic reactions of the Calvin cycle take place in the stroma of the chloroplast. The stroma is the fluid-filled space inside the chloroplast, surrounding the thylakoid membranes. This is where the enzymes necessary for the Calvin cycle are located, and where the carbon fixation and reduction reactions occur. The thylakoid membranes, on the other hand, are responsible for the light-dependent reactions of photosynthesis, not the Calvin cycle.Rate this question:
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- 37.
What is the primary function of the Calvin cycle?
- A.
Use ATP to release carbon dioxide
- B.
Use NADPH to release carbon dioxide
- C.
Split water and release oxygen
- D.
Transport RuBP out of the chloroplast
- E.
Synthesize simple sugars from carbon dioxide
Correct Answer
E. Synthesize simple sugars from carbon dioxideExplanation
The primary function of the Calvin cycle is to synthesize simple sugars from carbon dioxide. The cycle uses the energy from ATP and the reducing power of NADPH, both produced during the light-dependent reactions of photosynthesis, to convert carbon dioxide into glucose and other organic compounds. This process is known as carbon fixation and is essential for the production of carbohydrates, which serve as a source of energy and building blocks for plants and other organisms.Rate this question:
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- 38.
Which of the following is (are) required in the Calvin cycle?
- A.
CO2
- B.
ATP
- C.
RuBP
- D.
A and B only
- E.
A, B, and C
Correct Answer
E. A, B, and CExplanation
In the Calvin cycle, all three options - CO2, ATP, and RuBP - are required. CO2 is used as a carbon source to produce glucose, ATP provides energy for the reactions, and RuBP is the starting molecule that combines with CO2 to initiate the cycle. Therefore, all three components are necessary for the Calvin cycle to occur.Rate this question:
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- 39.
Which statement is false?
- A.
Thylakoid membranes contain the photosynthetic pigments.
- B.
The O2 released during photosynthesis comes from water.
- C.
RuBP is produced during cyclic electron flow in the light reactions of photosynthesis.
- D.
The light reactions of photosynthesis provide the energy for the Calvin cycle.
- E.
When chlorophyll is reduced, it gains electrons.
Correct Answer
C. RuBP is produced during cyclic electron flow in the light reactions of photosynthesis.Explanation
RuBP is not produced during cyclic electron flow in the light reactions of photosynthesis. RuBP, or ribulose-1,5-bisphosphate, is actually a molecule that is regenerated during the Calvin cycle, not during the cyclic electron flow. The cyclic electron flow is a process that occurs in the thylakoid membrane and generates ATP, but it does not produce RuBP.Rate this question:
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- 40.
One carbon dioxide molecule reacts in each "turn" of the Calvin cycle. How many turns of the cycle are required for the synthesis of one glucose molecule?
- A.
1
- B.
2
- C.
3
- D.
6
- E.
12
Correct Answer
D. 6Explanation
In the Calvin cycle, one carbon dioxide molecule is fixed and converted into glucose in each turn. Since one glucose molecule contains six carbon atoms, it would require six turns of the Calvin cycle to synthesize one glucose molecule.Rate this question:
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- 41.
All of the following statements are correct regarding the Calvin cycle except:
- A.
The energy source utilized is the ATP and NADPH obtained through the light reaction.
- B.
These reactions begin soon after sundown and end before sunrise.
- C.
The 5-carbon sugar RuBP is constantly being regenerated.
- D.
One of the end products is glyceraldehyde phosphate.
- E.
Rubisco attaches carbon dioxide to ribulose bisphosphate.
Correct Answer
B. These reactions begin soon after sundown and end before sunrise. -
- 42.
For the following, use the key below: A. light reactions alone B. the Calvin cycle alone C. both the light reactions and the Calvin cycle D. neither the light reactions nor the Calvin cycle E. occurs in the chloroplast but is not part of photosynthesis Produces molecular oxygen (O2)
Correct Answer
A
aExplanation
The correct answer is A, light reactions alone. The production of molecular oxygen (O2) occurs during the light reactions of photosynthesis. In this process, light energy is absorbed by chlorophyll and other pigments in the chloroplasts, leading to the splitting of water molecules. This results in the release of oxygen as a byproduct. The Calvin cycle, on the other hand, is responsible for the synthesis of glucose using the energy and products generated by the light reactions. Therefore, the production of molecular oxygen specifically occurs during the light reactions, making option A the correct answer.Rate this question:
- 43.
For the following, use the key below: A. light reactions alone B. the Calvin cycle alone C. both the light reactions and the Calvin cycle D. neither the light reactions nor the Calvin cycle E. occurs in the chloroplast but is not part of photosynthesis Produces NADH
Correct Answer
D
dExplanation
The correct answer is D, which means that the process does not involve either the light reactions or the Calvin cycle. The lowercase "d" is likely a typographical error and does not affect the explanation. This suggests that the process mentioned, which is the production of NADH, is not a part of photosynthesis. Photosynthesis involves the conversion of light energy into chemical energy in the form of glucose, and NADH is not directly produced in this process. Therefore, the correct answer is D, indicating that the process of producing NADH is not related to photosynthesis.Rate this question:
- 44.
For the following, use the key below: A. light reactions alone B. the Calvin cycle alone C. both the light reactions and the Calvin cycle D. neither the light reactions nor the Calvin cycle E. occurs in the chloroplast but is not part of photosynthesis Produces NADpH
Correct Answer
A
aExplanation
The correct answer is A, which means that the process produces NADPH. This suggests that the process involved is the light reactions alone, as NADPH is a product of the light reactions in photosynthesis. The Calvin cycle, on the other hand, produces NADP+ and not NADPH. Therefore, the correct answer indicates that the process is specifically related to the light reactions and not the Calvin cycle.Rate this question:
- 45.
For the following, use the key below: A. light reactions alone B. the Calvin cycle alone C. both the light reactions and the Calvin cycle D. neither the light reactions nor the Calvin cycle E. occurs in the chloroplast but is not part of photosynthesis Produces three-carbon sugars
Correct Answer
B
bExplanation
The correct answer is B, the Calvin cycle alone. The Calvin cycle is the second stage of photosynthesis and occurs in the stroma of the chloroplast. It is responsible for converting carbon dioxide into three-carbon sugars, such as glyceraldehyde-3-phosphate (G3P). The light reactions, on the other hand, occur in the thylakoid membrane and are responsible for capturing light energy and converting it into chemical energy in the form of ATP and NADPH. Therefore, the production of three-carbon sugars specifically occurs during the Calvin cycle and not during the light reactions.Rate this question:
- 46.
For the following, use the key below: A. light reactions alone B. the Calvin cycle alone C. both the light reactions and the Calvin cycle D. neither the light reactions nor the Calvin cycle E. occurs in the chloroplast but is not part of photosynthesis Inactive in the dark
Correct Answer
C
cExplanation
The correct answer is C. Inactive in the dark. This statement suggests that the process being referred to is photosynthesis, which is dependent on both the light reactions and the Calvin cycle. Photosynthesis cannot occur in the dark because it requires light energy to drive the light reactions, which produce ATP and NADPH, and the Calvin cycle, which uses these products to fix carbon dioxide and produce glucose. Therefore, the correct answer is C, indicating that both the light reactions and the Calvin cycle are necessary for photosynthesis to occur. The lowercase "c" is likely a typographical error and can be disregarded.Rate this question:
- 47.
For the following, use the key below: A. light reactions alone B. the Calvin cycle alone C. both the light reactions and the Calvin cycle D. neither the light reactions nor the Calvin cycle E. occurs in the chloroplast but is not part of photosynthesis Requires CO2
Correct Answer
B
bExplanation
The correct answer is B, the Calvin cycle alone. The Calvin cycle is a series of chemical reactions that occur in the chloroplasts of plants and algae. It is responsible for converting carbon dioxide into glucose, a process known as carbon fixation. This process does not require light and can occur in the absence of light reactions. Therefore, the statement "Requires CO2" is consistent with the Calvin cycle alone. The other options are not applicable because they either involve both light reactions and the Calvin cycle (option C), or neither light reactions nor the Calvin cycle (option D). Option E is incorrect because the Calvin cycle is indeed part of photosynthesis.Rate this question:
- 48.
For the following, use the key below: A. light reactions alone B. the Calvin cycle alone C. both the light reactions and the Calvin cycle D. neither the light reactions nor the Calvin cycle E. occurs in the chloroplast but is not part of photosynthesis Requires glucose
Correct Answer
D
dExplanation
The correct answer is D,d. This answer indicates that the process described does not require either the light reactions or the Calvin cycle. It suggests that the process is not part of photosynthesis and does not produce glucose.Rate this question:
- 49.
Which of the following is (are) true of the enzyme ribulose bisphosphate carboxylase?
- A.
It participates in the Calvin cycle.
- B.
It catalyzes a phosphorylation reaction.
- C.
It has an affinity for both O2 and CO2.
- D.
A and C are true.
- E.
A, B, and C are true.
Correct Answer
D. A and C are true.Explanation
The enzyme ribulose bisphosphate carboxylase participates in the Calvin cycle, which is a series of reactions that occur in the chloroplasts of plants during photosynthesis. This enzyme is responsible for catalyzing the carboxylation of ribulose bisphosphate, a key step in the Calvin cycle. Additionally, ribulose bisphosphate carboxylase has an affinity for both O2 and CO2, allowing it to bind to and react with both molecules. Therefore, the correct answer is A and C are true.Rate this question:
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- 50.
What are the substrates (normal reactants) for the enzyme RuBP carboxylase?
- A.
CO2 and O2
- B.
CO2 and glucose
- C.
ATP and NADPH
- D.
Triose-P, glucose, and CO2
- E.
CO2 and ATP
Correct Answer
A. CO2 and O2Explanation
The enzyme RuBP carboxylase is responsible for the fixation of carbon dioxide during photosynthesis. It catalyzes the reaction between carbon dioxide (CO2) and ribulose-1,5-bisphosphate (RuBP) to produce two molecules of 3-phosphoglycerate (3-PGA). However, due to a process called photorespiration, RuBP carboxylase can also react with oxygen (O2) instead of carbon dioxide. This leads to the production of one molecule of 3-PGA and one molecule of 2-phosphoglycolate, which is eventually converted into carbon dioxide. Therefore, the substrates for RuBP carboxylase are both CO2 and O2.Rate this question:
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.JPG "This figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?")
.JPG "What wavelength of light is most effective in driving photosynthesis?")
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