Question 1

Conversion of carbon dioxide into carbohydrates relies on energy from

Accepted Answer

A)  ATP. 
B)  NAPD+. 
C)  ADP. 
D)  NAD+. 
E)  NADH. 
A)  ATP. 
B)  NAPD+. 
C)  ADP. 
D)  NAD+. 
E)  NADH.

Question 2

Refer to the table below containing data collected from experiments using chloroplasts isolated from leaves taken from living spinach plants.In the experiments, measurements were taken of the catalytic activity of the enzyme sedoheptulose bisphosphatase (SBP), which operates in the part of the Calvin cycle that regenerates ribulose 1,5-bisphosphate (RuBP).The chloroplasts were broken open using a blender, and the resulting mixture was centrifuged and the pellet discarded.The enzyme SBP was present in the supernatant and could be assayed by adding its substrates and measuring how much product was formed from the reaction it catalyzed.Depending on additional treatments listed in the table, the catalytic activity of SBP varied as shown.   What do the data suggest about the role of ferredoxin and thioredoxin in the function of this enzyme? Explain your reasoning.

Accepted Answer

The data suggest that the enzyme SBP is

Question 3

If a plant has plenty of NADPH available but is running low on ATP, how does the plant make up the ATP deficit during the daylight hours?

Accepted Answer

A)  It uses photorespiration. 
B)  It uses noncyclic photophosphorylation. 
C)  It uses cyclic photophosphorylation. 
D)  It decreases the rate of chemiosmosis. 
E)  It increases the rate of the Calvin cycle. 
A)  It uses photorespiration. 
B)  It uses noncyclic photophosphorylation. 
C)  It uses cyclic photophosphorylation. 
D)  It decreases the rate of chemiosmosis. 
E)  It increases the rate of the Calvin cycle.

Question 4

Which statement is false?

Accepted Answer

A)  PEP carboxylase and rubisco both catalyze carboxylase reactions. 
B)  PEP carboxylase is found only in the cytosol of mesophyll cells, whereas rubisco is found in the cytosol of both mesophyll and bundle sheath cells. 
C)  PEP carboxylase and rubisco both use oxygen as a substrate. 
D)  PEP carboxylase and rubisco are both proteins. 
E)  PEP carboxylase requires a three-carbon reactant, while rubisco requires a five-carbon reactant. 
A)  PEP carboxylase and rubisco both catalyze carboxylase reactions. 
B)  PEP carboxylase is found only in the cytosol of mesophyll cells, whereas rubisco is found in the cytosol of both mesophyll and bundle sheath cells. 
C)  PEP carboxylase and rubisco both use oxygen as a substrate. 
D)  PEP carboxylase and rubisco are both proteins. 
E)  PEP carboxylase requires a three-carbon reactant, while rubisco requires a five-carbon reactant.

Question 5

In cacti, CO2 is fixed during the night in a four-carbon molecule and stored in _______ for use in the Calvin cycle during the day.

Accepted Answer

A)  the stems, roots, and leaves 
B)  the vacuoles of mesophyll cells 
C)  sugar molecules 
D)  the stroma 
E)  the thylakoid lumen 
A)  the stems, roots, and leaves 
B)  the vacuoles of mesophyll cells 
C)  sugar molecules 
D)  the stroma 
E)  the thylakoid lumen

Question 6

One reason the absorption spectrum of chlorophyll a is not identical to the action spectrum of photosynthesis is that

Accepted Answer

A)  accessory pigments also absorb energy to drive photosynthesis. 
B)  chlorophyll a absorbs both red light and blue light. 
C)  chlorophyll a reflects green light. 
D)  different wavelengths of light have different energies. 
E)  chlorophyll a can be activated by absorbing a photon of light. 
A)  accessory pigments also absorb energy to drive photosynthesis. 
B)  chlorophyll a absorbs both red light and blue light. 
C)  chlorophyll a reflects green light. 
D)  different wavelengths of light have different energies. 
E)  chlorophyll a can be activated by absorbing a photon of light.

Question 7

Which molecule(s) shuttle(s) between the mesophyll and bundle sheath cells in C4 plants during carbon fixation?

Accepted Answer

A)  A four-carbon molecule only 
B)  A three-carbon molecule only 
C)  A two-carbon molecule only 
D)  A four-carbon molecule and a three-carbon molecule 
E)  Two different four-carbon molecules 
A)  A four-carbon molecule only 
B)  A three-carbon molecule only 
C)  A two-carbon molecule only 
D)  A four-carbon molecule and a three-carbon molecule 
E)  Two different four-carbon molecules

Question 8

To study the mechanism of excitation in the reaction center of a photosystem, on what timescale would you need to capture data?

Accepted Answer

A)  Seconds 
B)  Milliseconds (10-3 sec) 
C)  Microseconds (10-6 sec) 
D)  Nanoseconds (10-9 sec) 
E)  Picoseconds (10-12 sec) 
A)  Seconds 
B)  Milliseconds (10-3 sec) 
C)  Microseconds (10-6 sec) 
D)  Nanoseconds (10-9 sec) 
E)  Picoseconds (10-12 sec)

Question 9

During cyclic photophosphorylation, the energy of photons is converted into the chemical energy of the product, which is _______.

Accepted Answer

The answer of During cyclic photophosphorylation, the energy of photons...

Question 10

Atmospheric oxygen levels have remained constant at 21 percent for thousands of years.Scientists have speculated that low carbon dioxide levels in the atmosphere could be responsible for this steady O2 level.Considering that the majority of plants on Earth are C3 plants, explain how low carbon dioxide levels could have helped maintain constant oxygen levels on the planet.

Accepted Answer

Low carbon dioxide levels kept

Question 11

The following half-reaction is used to describe the chemical change that occurs to oxygen atoms in water during photosynthesis:
12 H2O F1F1F1S1F1F1F10 24 H+ + 24 e− + 6 O2
This half-reaction illustrates that oxygen atoms in water undergo _______ to form O2.

Accepted Answer

Question 12

Which sequence describes the processes of the Calvin cycle?

Accepted Answer

A)  Carbon fixation F1F1F1S1F1F1F10F1F1F1S1F1F1F10reduction and sugar formation F1F1F1S1F1F1F10F1F1F1S1F1F1F10regeneration of RuBP 
B)  Regeneration of RuBP F1F1F1S1F1F1F10F1F1F1S1F1F1F10carbon fixation F1F1F1S1F1F1F10F1F1F1S1F1F1F10reduction and sugar formation 
C)  Reduction and sugar formation F1F1F1S1F1F1F10F1F1F1S1F1F1F10carbon fixation F1F1F1S1F1F1F10F1F1F1S1F1F1F10regeneration of RuBP 
D)  Carbon fixation F1F1F1S1F1F1F10F1F1F1S1F1F1F10regeneration of RuBP F1F1F1S1F1F1F10F1F1F1S1F1F1F10reduction and sugar formation 
E)  Regeneration of RuBP F1F1F1S1F1F1F10F1F1F1S1F1F1F10reduction and sugar formation F1F1F1S1F1F1F10F1F1F1S1F1F1F10carbon fixation 
A)  Carbon fixation F1F1F1S1F1F1F10F1F1F1S1F1F1F10reduction and sugar formation F1F1F1S1F1F1F10F1F1F1S1F1F1F10regeneration of RuBP 
B)  Regeneration of RuBP F1F1F1S1F1F1F10F1F1F1S1F1F1F10carbon fixation F1F1F1S1F1F1F10F1F1F1S1F1F1F10reduction and sugar formation 
C)  Reduction and sugar formation F1F1F1S1F1F1F10F1F1F1S1F1F1F10carbon fixation F1F1F1S1F1F1F10F1F1F1S1F1F1F10regeneration of RuBP 
D)  Carbon fixation F1F1F1S1F1F1F10F1F1F1S1F1F1F10regeneration of RuBP F1F1F1S1F1F1F10F1F1F1S1F1F1F10reduction and sugar formation 
E)  Regeneration of RuBP F1F1F1S1F1F1F10F1F1F1S1F1F1F10reduction and sugar formation F1F1F1S1F1F1F10F1F1F1S1F1F1F10carbon fixation

Question 13

In the first phase of photosynthesis, a series of reactions converts light energy into ATP and NADPH.These reactions are referred to as

Accepted Answer

A)  reduction. 
B)  dark reactions. 
C)  carbon fixation. 
D)  light reactions. 
E)  ATP/NADPH synthesis. 
A)  reduction. 
B)  dark reactions. 
C)  carbon fixation. 
D)  light reactions. 
E)  ATP/NADPH synthesis.

Question 14

When a photon is absorbed by a molecule, the photon

Accepted Answer

A)  loses its ability to generate any energy. 
B)  raises the molecule from a ground state of low energy to an excited state. 
C)  affects the molecule in ways that are not clearly understood. 
D)  causes a change in the velocity of the wavelengths. 
E)  splits water into hydrogen and oxygen. 
A)  loses its ability to generate any energy. 
B)  raises the molecule from a ground state of low energy to an excited state. 
C)  affects the molecule in ways that are not clearly understood. 
D)  causes a change in the velocity of the wavelengths. 
E)  splits water into hydrogen and oxygen.

Question 15

When the pH of the stroma shifts from 7 to 8 under illumination,

Accepted Answer

A)  four Calvin cycle enzymes become inactivated. 
B)  rubisco becomes activated. 
C)  disulfide bonds in ferredoxin become oxidized. 
D)  thioredoxin becomes oxidized. 
E)  ATP is hydrolyzed. 
A)  four Calvin cycle enzymes become inactivated. 
B)  rubisco becomes activated. 
C)  disulfide bonds in ferredoxin become oxidized. 
D)  thioredoxin becomes oxidized. 
E)  ATP is hydrolyzed.

Question 16

Some anaerobic bacteria carry out anoxygenic photosynthesis using the net chemical conversion shown below:
 6 CO2 + 12 H2S F1F1F1S1F1F1F10 C6H12O6 + 6 H2O + 12 S
The discovery of this type of photosynthesis provided evidence for which aspect of the photosynthetic process?

Accepted Answer

A)  In oxygenic photosynthesis, the source of oxygen atoms is water, not carbon dioxide. 
B)  Two photosystems are used in noncyclic electron transport. 
C)  Photosynthesis consists of two stages of reactions: light reactions and light-independent reactions. 
D)  Carbon fixation occurs independent of the presence of light. 
E)  The carrier molecules ATP and NADPH are important intermediates in the photosynthetic process. 
A)  In oxygenic photosynthesis, the source of oxygen atoms is water, not carbon dioxide. 
B)  Two photosystems are used in noncyclic electron transport. 
C)  Photosynthesis consists of two stages of reactions: light reactions and light-independent reactions. 
D)  Carbon fixation occurs independent of the presence of light. 
E)  The carrier molecules ATP and NADPH are important intermediates in the photosynthetic process.

Question 17

How many six-carbon sugar molecules are produced by the Calvin cycle when 18 CO2 are fixed?

Accepted Answer

A)  3 
B)  9 
C)  18 
D)  36 
E)  44 
A)  3 
B)  9 
C)  18 
D)  36 
E)  44

Question 18

The most important wavelengths of light for photosynthesis are

Accepted Answer

A)  the UV wavelengths. 
B)  the visible wavelengths between 400 and 525 nm only. 
C)  the IR wavelengths. 
D)  the visible wavelengths between 400 and 525 nm and between 600 and 700 nm. 
E)  the visible wavelengths between 600 and 700 nm only. 
A)  the UV wavelengths. 
B)  the visible wavelengths between 400 and 525 nm only. 
C)  the IR wavelengths. 
D)  the visible wavelengths between 400 and 525 nm and between 600 and 700 nm. 
E)  the visible wavelengths between 600 and 700 nm only.

Question 19

Refer to the table below.   How do these two photosynthetic processes compare?

Accepted Answer

A)  The electron acceptor in both plants and purple sulfur bacteria is H2O. 
B)  The electron donor in both plants and purple sulfur bacteria is CO2. 
C)  The electron acceptor in plants is H2O, and the electron acceptor in purple sulfur bacteria is H2S. 
D)  The electron donor in plants is H2O, and the electron donor in purple sulfur bacteria is H2S. 
E)  The electron donor in plants is H2O, and the electron donor in purple sulfur bacteria is CO2. 
A)  The electron acceptor in both plants and purple sulfur bacteria is H2O. 
B)  The electron donor in both plants and purple sulfur bacteria is CO2. 
C)  The electron acceptor in plants is H2O, and the electron acceptor in purple sulfur bacteria is H2S. 
D)  The electron donor in plants is H2O, and the electron donor in purple sulfur bacteria is H2S. 
E)  The electron donor in plants is H2O, and the electron donor in purple sulfur bacteria is CO2.

Question 20

The carboxylation reaction of PEP carboxylase produces

Accepted Answer

A)  oxaloacetate and ATP. 
B)  oxaloacetate, ATP, and O2. 
C)  phosphoenolpyruvate (PEP). 
D)  oxaloacetate and CO2. 
E)  oxaloacetate only. 
A)  oxaloacetate and ATP. 
B)  oxaloacetate, ATP, and O2. 
C)  phosphoenolpyruvate (PEP). 
D)  oxaloacetate and CO2. 
E)  oxaloacetate only.

Exam 10: Photosynthesis: Energy From Sunlight

Conversion of carbon dioxide into carbohydrates relies on energy from

If a plant has plenty of NADPH available but is running low on ATP, how does the plant make up the ATP deficit during the daylight hours?

Which statement is false?

In cacti, CO2 is fixed during the night in a four-carbon molecule and stored in _______ for use in the Calvin cycle during the day.

One reason the absorption spectrum of chlorophyll a is not identical to the action spectrum of photosynthesis is that

Which molecule(s) shuttle(s) between the mesophyll and bundle sheath cells in C4 plants during carbon fixation?

To study the mechanism of excitation in the reaction center of a photosystem, on what timescale would you need to capture data?

During cyclic photophosphorylation, the energy of photons is converted into the chemical energy of the product, which is _______.

The following half-reaction is used to describe the chemical change that occurs to oxygen atoms in water during photosynthesis: 12 H2O  24 H+ + 24 e− + 6 O2 This half-reaction illustrates that oxygen atoms in water undergo _______ to form O2.

Which sequence describes the processes of the Calvin cycle?

In the first phase of photosynthesis, a series of reactions converts light energy into ATP and NADPH.These reactions are referred to as

When a photon is absorbed by a molecule, the photon

When the pH of the stroma shifts from 7 to 8 under illumination,

Some anaerobic bacteria carry out anoxygenic photosynthesis using the net chemical conversion shown below: 6 CO2 + 12 H2S  C6H12O6 + 6 H2O + 12 S The discovery of this type of photosynthesis provided evidence for which aspect of the photosynthetic process?

How many six-carbon sugar molecules are produced by the Calvin cycle when 18 CO2 are fixed?

The most important wavelengths of light for photosynthesis are

Refer to the table below. How do these two photosynthetic processes compare?

The carboxylation reaction of PEP carboxylase produces

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In cacti, CO₂ is fixed during the night in a four-carbon molecule and stored in _______ for use in the Calvin cycle during the day.

Which molecule(s) shuttle(s) between the mesophyll and bundle sheath cells in C₄ plants during carbon fixation?

The following half-reaction is used to describe the chemical change that occurs to oxygen atoms in water during photosynthesis: 12 H₂O  24 H⁺ + 24 e⁻ + 6 O₂ This half-reaction illustrates that oxygen atoms in water undergo _______ to form O₂.

Some anaerobic bacteria carry out anoxygenic photosynthesis using the net chemical conversion shown below: 6 CO₂ + 12 H₂S  C₆H₁₂O₆ + 6 H₂O + 12 S The discovery of this type of photosynthesis provided evidence for which aspect of the photosynthetic process?

How many six-carbon sugar molecules are produced by the Calvin cycle when 18 CO₂ are fixed?