AP Biology Chapter 10 Practice Test

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What are the products of the light reactions that are subsequently used by the Calvin cycle?
- Oxygen and carbon dioxide
- Carbon dioxide and RuBP
- Water and carbon
- Electrons and photons
- ATP and NADPH

About This Quiz

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!

AP Biology Chapter 10 Practice Test - Quiz

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2.

The light reactions of photosynthesis supply the Calvin cycle with
- Light energy.
- CO2 and ATP.
- H2O and NADPH.
- ATP and NADPH.
- Sugar and O2.
Correct Answer

A. ATP and NADPH.

Explanation

The light reactions of 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, the second stage of photosynthesis, to convert carbon dioxide into glucose. Therefore, ATP and NADPH are the correct answer because they provide the energy needed for the Calvin cycle to occur.

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3.

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
c

Explanation
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.

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4.

Which of the following statements is a correct distinction between autotrophs and heterotrophs?
- Only heterotrophs require chemical compounds from the environment.
- Cellular respiration is unique to heterotrophs.
- Only heterotrophs have mitochondria.
- Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.
- Only heterotrophs require oxygen.
Correct Answer

A. Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.

Explanation

Autotrophs are able to produce their own food using inorganic compounds like CO2 and other nutrients, while heterotrophs rely on obtaining organic compounds from their environment. This statement correctly distinguishes autotrophs from heterotrophs by highlighting their different abilities to nourish themselves.

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1
5.

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
- CO2 and glucose
- H2O and O2
- ADP, Pi, and NADP+
- Electrons and H+
- ATP and NADPH
Correct Answer

A. ATP and NADPH

Explanation

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.

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6.

What is the primary function of the light reactions of photosynthesis?
- To produce energy-rich glucose from carbon dioxide and water
- To produce ATP and NADPH
- To produce NADPH used in respiration
- To convert light energy to the chemical energy of PGAL
- To use ATP to make glucose
Correct Answer

A. To produce ATP and NADPH

Explanation

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.

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7.

The reaction-center chlorophyll of photosystem I is known as P700 because
- There are 700 chlorophyll molecules in the center.
- This pigment is best at absorbing light with a wavelength of 700 nm.
- There are 700 photosystem I components to each chloroplast.
- It absorbs 700 photons per microsecond.
- The plastoquinone reflects light with a wavelength of 700 nm.
Correct Answer

A. 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.

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8.

Where does the Calvin cycle take place?
- Stroma of the chloroplast
- Thylakoid membrane
- Cytoplasm surrounding the chloroplast
- Chlorophyll molecule
- Outer membrane of the chloroplast
Correct Answer

A. Stroma of the chloroplast

Explanation

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.

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9.

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
b

Explanation
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.

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1
10.

Organisms that can exist with light as an energy source and an inorganic form of carbon and other raw materials
- Are called photoautotrophs.
- Do not exist in nature.
- Are called heterotrophs.
- Are best classified as decomposers.
- 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.

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11.

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
d

Explanation
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.

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12.

Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?
- The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.
- 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.
- 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.
- The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provides the light reactions with water to split.
- 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.

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13.

Where do the enzymatic reactions of the Calvin cycle take place?
- Stroma of the chloroplast
- Thylakoid membranes
- Outer membrane of the chloroplast
- Electron transport chain
- Thylakoid space
Correct Answer

A. Stroma of the chloroplast

Explanation

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.

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14.

What is the primary function of the Calvin cycle?
- Use ATP to release carbon dioxide
- Use NADPH to release carbon dioxide
- Split water and release oxygen
- Transport RuBP out of the chloroplast
- Synthesize simple sugars from carbon dioxide
Correct Answer

A. Synthesize simple sugars from carbon dioxide

Explanation

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.

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15.

All of the following statements are correct regarding the Calvin cycle except:
- The energy source utilized is the ATP and NADPH obtained through the light reaction.
- These reactions begin soon after sundown and end before sunrise.
- The 5-carbon sugar RuBP is constantly being regenerated.
- One of the end products is glyceraldehyde phosphate.
- Rubisco attaches carbon dioxide to ribulose bisphosphate.
Correct Answer

A. These reactions begin soon after sundown and end before sunrise.
16.

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
a

Explanation
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.

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0
17.

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?
- Red and yellow
- Blue and violet
- Green and yellow
- Blue, green, and red
- Green, blue, and violet
Correct Answer

A. Red and yellow

Explanation

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.

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18.

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
a

Explanation
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.

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19.

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
b

Explanation
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.

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20.

Which of the following statements about the light reactions of photosynthesis are true?
- The splitting of water molecules provides a source of electrons.
- Chlorophyll (and other pigments) absorb light energy, which excites electrons.
- ATP is generated by photophosphorylation.
- Only A and C are true.
- A, B, and C are true.
Correct Answer

A. 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.

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21.

What are the products of noncyclic photophosphorylation?
- Heat and fluorescence
- ATP and P700
- ATP and NADPH
- ADP and NADP
- P700 and P680
Correct Answer

A. ATP and NADPH

Explanation

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.

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22.

Why are C4 plants able to photosynthesize with no apparent photorespiration?
- They do not participate in the Calvin cycle.
- They use PEP carboxylase to initially fix CO2.
- They are adapted to cold, wet climates.
- They conserve water more efficiently.
- They exclude oxygen from their tissues.
Correct Answer

A. They use PEP carboxylase to initially fix CO2.

Explanation

C4 plants are able to photosynthesize with no apparent photorespiration because they use PEP carboxylase to initially fix CO2. This enzyme has a higher affinity for CO2 than for oxygen, allowing the plants to efficiently fix carbon dioxide and minimize the wasteful process of photorespiration. By using PEP carboxylase, C4 plants can effectively capture CO2 even in conditions of high oxygen concentration, making them more efficient at photosynthesis.

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23.

How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
- 2
- 4
- 6
- 8
- 10
Correct Answer

A. 6

Explanation

In the process of photosynthesis, carbon dioxide molecules are used to synthesize glucose. The molecule that accepts carbon dioxide during this process is called RuBP (ribulose-1,5-bisphosphate). To produce one molecule of glucose, six molecules of carbon dioxide must be added to RuBP. This is because glucose has six carbon atoms, and each carbon atom comes from a carbon dioxide molecule. Therefore, the correct answer is 6.

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24.

What wavelength of light is most effective in driving photosynthesis?
- 420 mm
- 475 mm
- 575 mm
- 625 mm
- 730 mm
Correct Answer

A. 420 mm

Explanation

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.

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25.

Where is the electron transport chain found in plant cells?
- Thylakoid membranes of chloroplasts
- Stroma of chloroplasts
- Inner membrane of mitochondria
- Matrix of mitochondria
- Cytoplasm
Correct Answer

A. Thylakoid membranes of chloroplasts

Explanation

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.

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26.

Of the following, what do both mitochondria and chloroplasts have in common?
- Thylakoid membranes
- Chemiosmosis
- ATP synthase
- B and C only
- A, B, and C
Correct Answer

A. B and C only

Explanation

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.

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27.

Which statement is false?
- Thylakoid membranes contain the photosynthetic pigments.
- The O2 released during photosynthesis comes from water.
- RuBP is produced during cyclic electron flow in the light reactions of photosynthesis.
- The light reactions of photosynthesis provide the energy for the Calvin cycle.
- When chlorophyll is reduced, it gains electrons.
Correct Answer

A. 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.

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28.

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
a

Explanation
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.

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29.

Which of the following sequences correctly represents the flow of electrons during photosynthesis?
- NADPH → O2 → CO2
- H2O → NADPH → Calvin cycle
- NADPH → chlorophyll → Calvin cycle
- H2O → photosystem I → photosystem II
- NADPH → electron transport chain → O2
Correct Answer

A. H2O → NADPH → Calvin cycle
30.

In the thylakoid membranes, what is the main role of the antenna pigment molecules?
- Split water and release oxygen to the reaction-center chlorophyll
- Harvest photons and transfer light energy to the reaction-center chlorophyll
- Synthesize ATP from ADP and Pi
- Transfer electrons to ferredoxin and then NADPH
- Concentrate photons within the stroma
Correct Answer

A. Harvest photons and transfer light energy to the reaction-center chlorophyll

Explanation

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.

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31.

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?
- Photosystem II
- Photosystem I
- Cyclic electron flow
- Noncyclic electron flow
- Chlorophyll
Correct Answer

A. Cyclic electron flow

Explanation

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.

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32.

Which of the following is (are) required in the Calvin cycle?
- CO2
- ATP
- RuBP
- A and B only
- A, B, and C
Correct Answer

A. A, B, and C

Explanation

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.

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33.

In C4 photosynthesis, carbon fixation takes place in the ________ cells, and then is transferred as malic or aspartic acid to ________ cells, where carbon dioxide is released for entry into the Calvin cycle.
- Mesophyll; bundle-sheath
- Stomatal; mesophyll
- Bundle-sheath; epidermal
- Epidermal; mesophyll
- Stomatal; epidermal
Correct Answer

A. Mesophyll; bundle-sheath

Explanation

In C4 photosynthesis, carbon fixation takes place in the mesophyll cells, where carbon dioxide is initially converted into a four-carbon compound. This four-carbon compound is then transferred as malic or aspartic acid to the bundle-sheath cells, where carbon dioxide is released for entry into the Calvin cycle.

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34.

All of the events listed below occur in the light reactions of photosynthesis except
- Oxygen is produced.
- NADP+ is reduced to NADPH.
- Carbon dioxide is incorporated into PGA.
- ADP is phosphorylated to yield ATP.
- Light is absorbed and funneled to reaction-center chlorophyll a.
Correct Answer

A. 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.

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35.

In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from
- The stroma to the photosystem II.
- The matrix to the stroma.
- The stroma to the thylakoid space.
- The intermembrane space to the matrix.
- ATP synthase to NADP+ reductase.
Correct Answer

A. 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.

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36.

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
b

Explanation
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.

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37.

Plants that fix CO2 into organic acids at night when the stomata are open and carry out the Calvin cycle during the day when the stomata are closed are called
- C3 plants.
- C4 plants.
- CAM plants.
- B and C only.
- A, B, and C
Correct Answer

A. CAM plants.

Explanation

CAM plants, or Crassulacean Acid Metabolism plants, are able to fix CO2 into organic acids at night when their stomata are open. During the day, when the stomata are closed to prevent water loss, they carry out the Calvin cycle using the stored organic acids. This adaptation allows CAM plants to survive in arid environments with limited water availability. C3 plants and C4 plants have different mechanisms for fixing CO2 and do not exhibit this specific behavior. Therefore, the correct answer is CAM plants.

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38.

In mechanism, photophosphorylation is most similar to
- Substrate-level phosphorylation in glycolysis.
- Oxidative phosphorylation in cellular respiration.
- The Calvin cycle.
- Carbon fixation.
- Reduction of NADP+.
Correct Answer

A. Oxidative phosphorylation in cellular respiration.

Explanation

Photophosphorylation is the process of using light energy to generate ATP in photosynthesis. Similarly, oxidative phosphorylation is the process of generating ATP in cellular respiration by utilizing energy from the electron transport chain. Both processes involve the generation of ATP through the transfer of electrons and the establishment of a proton gradient across a membrane. Therefore, oxidative phosphorylation in cellular respiration is the most similar process to photophosphorylation.

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39.

In what respect are the photosynthetic adaptations of C4 plants and CAM plants similar?
- In both cases, only photosystem I is used.
- Both types of plants make sugar without the Calvin cycle.
- In both cases, an enzyme other than rubisco carries out the first step in carbon fixation.
- Both types of plants make most of their sugar in the dark.
- Neither C4 plants nor CAM plants have thylakoids.
Correct Answer

A. In both cases, an enzyme other than rubisco carries out the first step in carbon fixation.

Explanation

Both C4 plants and CAM plants have a similar photosynthetic adaptation where an enzyme other than rubisco carries out the first step in carbon fixation. This means that instead of using the enzyme rubisco, which is the primary enzyme involved in carbon fixation in most plants, these types of plants use a different enzyme to initiate the process. This adaptation allows them to efficiently capture and utilize carbon dioxide, especially in environments with high temperatures or limited water availability.

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40.

Which of the following does not occur during the Calvin cycle?
- Carbon fixation
- Oxidation of NADPH
- Release of oxygen
- Regeneration of the CO2 acceptor
- Consumption of ATP
Correct Answer

A. Release of oxygen

Explanation

During the Calvin cycle, carbon fixation occurs as carbon dioxide is converted into organic molecules. The oxidation of NADPH also takes place, where NADPH is oxidized to NADP+. The regeneration of the CO2 acceptor is another step in the Calvin cycle, as the molecule that accepts the carbon dioxide is regenerated. Additionally, the consumption of ATP is necessary for the energy required in the Calvin cycle. However, the release of oxygen does not occur during the Calvin cycle. Oxygen is produced as a byproduct of the light-dependent reactions of photosynthesis, not during the Calvin cycle itself.

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41.

This figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?
- Green and yellow wavelengths inhibit the absorption of red and blue wavelengths.
- Bright sunlight destroys photosynthetic pigments.
- Oxygen given off during photosynthesis interferes with the absorption of light.
- Other pigments absorb light in addition to chlorophyll a.
- Aerobic bacteria take up oxygen which changes the measurement of the rate of photosynthesis.
Correct Answer

A. 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.

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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 NADH

Correct Answer
D
d

Explanation
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.

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43.

Which type of organism obtains energy by metabolizing molecules produced by other organisms?
- Autotrophs
- Heterotrophs
- Decomposers
- B and C
- A, B, and C
Correct Answer

A. B and C

Explanation

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.

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44.

What does the chemiosmotic process in chloroplasts involve?
- Establishment of a proton gradient
- Diffusion of electrons through the thylakoid membrane
- Reduction of water to produce ATP energy
- Movement of water by osmosis into the thylakoid space from the stroma
- Formation of glucose, using carbon dioxide, NADPH, and ATP
Correct Answer

A. Establishment of a proton gradient

Explanation

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.

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45.

All of the following are directly associated with photosystem II except
- Extraction of hydrogen electrons from the splitting of water.
- Release of oxygen.
- Harvesting of light energy by chlorophyll.
- NADP+ reductase.
- P680 reaction-center chlorophyll.
Correct Answer

A. 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.

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46.

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?
- 1
- 2
- 3
- 6
- 12
Correct Answer

A. 6

Explanation

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.

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47.

CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they
- Fix CO2 into organic acids during the night.
- Fix CO2 into sugars in the bundle-sheath cells.
- Fix CO2 into pyruvate in the mesophyll cells.
- Use the enzyme phosphofructokinase, which outcompetes rubisco for CO2.
- Use photosystems I and II at night.
Correct Answer

A. Fix CO2 into organic acids during the night.

Explanation

CAM plants keep stomata closed in daytime to reduce water loss. They fix CO2 into organic acids during the night as a strategy to minimize water loss while still obtaining the necessary carbon dioxide for photosynthesis. This allows them to store the fixed CO2 in the form of organic acids, which can be used during the day when the stomata are closed. By fixing CO2 into organic acids, CAM plants can effectively adapt to arid conditions and conserve water.

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1
48.

In C3 plants the conservation of water promotes
- Photorespiration.
- The light reactions.
- A shift to C4 photosynthesis.
- The opening of stomata.
- Photosynthesis.
Correct Answer

A. Photorespiration.

Explanation

In C3 plants, the conservation of water promotes photorespiration. Photorespiration is a process that occurs in plants when there is a shortage of carbon dioxide and excess oxygen. It is a wasteful process that reduces the efficiency of photosynthesis and can lead to a loss of energy and resources for the plant. To conserve water, C3 plants close their stomata, which reduces the intake of carbon dioxide and increases the concentration of oxygen in the leaf. This promotes photorespiration as the excess oxygen inhibits the normal photosynthetic process. Therefore, the conservation of water in C3 plants promotes photorespiration.

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49.

In an experiment studying photosynthesis performed during the day, you provide a plant with radioactive carbon (14C) dioxide as a metabolic tracer. The 14C is incorporated first into oxaloacetate. The plant is best characterized as a
- C4 plant.
- C3 plant.
- CAM plant.
- Heterotroph.
- Chemoautotroph.
Correct Answer

A. C4 plant.

Explanation

In C4 plants, the first stable product of carbon fixation is a four-carbon compound called oxaloacetate. This is in contrast to C3 plants, where the first stable product is a three-carbon compound called 3-phosphoglycerate. CAM plants also initially fix carbon as a C3 compound, but they do so at night and store it as an organic acid before using it during the day. Heterotrophs obtain their carbon from organic compounds, while chemoautotrophs use inorganic chemicals as a source of energy and carbon dioxide as a source of carbon. Therefore, the plant in this experiment is best characterized as a C4 plant.

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What are the products of the light reactions that are subsequently used by the Calvin cycle?

Quiz Preview

The light reactions of photosynthesis supply the Calvin cycle with

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

Which of the following statements is a correct distinction between autotrophs and heterotrophs?

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

What is the primary function of the light reactions of photosynthesis?

The reaction-center chlorophyll of photosystem I is known as P700 because

Where does the Calvin cycle take place?

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

Organisms that can exist with light as an energy source and an inorganic form of carbon and other raw materials

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

Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?

Where do the enzymatic reactions of the Calvin cycle take place?

What is the primary function of the Calvin cycle?

All of the following statements are correct regarding the Calvin cycle except:

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

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. 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+

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

Which of the following statements about the light reactions of photosynthesis are true?

What are the products of noncyclic photophosphorylation?

Why are C4 plants able to photosynthesize with no apparent photorespiration?

How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?

What wavelength of light is most effective in driving photosynthesis?

Where is the electron transport chain found in plant cells?

Of the following, what do both mitochondria and chloroplasts have in common?

Which statement is false?

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)

Which of the following sequences correctly represents the flow of electrons during photosynthesis?

In the thylakoid membranes, what is the main role of the antenna pigment molecules?

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?

Which of the following is (are) required in the Calvin cycle?

In C4 photosynthesis, carbon fixation takes place in the ________ cells, and then is transferred as malic or aspartic acid to ________ cells, where carbon dioxide is released for entry into the Calvin cycle.

All of the events listed below occur in the light reactions of photosynthesis except

In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from

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

Plants that fix CO2 into organic acids at night when the stomata are open and carry out the Calvin cycle during the day when the stomata are closed are called

In mechanism, photophosphorylation is most similar to

In what respect are the photosynthetic adaptations of C4 plants and CAM plants similar?

Which of the following does not occur during the Calvin cycle?

This figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?

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

Which type of organism obtains energy by metabolizing molecules produced by other organisms?

What does the chemiosmotic process in chloroplasts involve?

All of the following are directly associated with photosystem II except

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?

CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they

In C3 plants the conservation of water promotes

In an experiment studying photosynthesis performed during the day, you provide a plant with radioactive carbon (14C) dioxide as a metabolic tracer. The 14C is incorporated first into oxaloacetate. The plant is best characterized as a

In C4 photosynthesis, carbon fixation takes place in the cells, and then is transferred as malic or aspartic acid to cells, where carbon dioxide is released for entry into the Calvin cycle.