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79 terms

BIO 201 UNCW Chapter 8 Brooker

STUDY
PLAY
Which of the following are examples of redox reactions that occur during photosynthesis?

A. The removal of low energy electrons from water
B. The generation of NADPH
C. The transfer of high-energy electrons from a pigment molecule to the primary electron acceptor
D. The excitement of an electrons
a b c
Carotenoids are:

membranous structures in a chloroplast
pigments
gas exchange structures
chlorophyll variants
photosystems
pigments
The word "photosynthesis," "photo" refers to the ___ reactions, in which light energy is captures, while "synthesis" refers to the synthesis of _____ in the Calvin cylce.
light
carbohydrates
The function of both NAD+ in cellular respiration, and NADP+ in photosynthesis, are similar in that they both act as:
a. an oxidizing agent
b. an electron carrier that can accept two electrons
c. a reducing agent
d. a photosystem adapted to capture light
a, b
Electromagnetic radiation travels as:

waves
fields
particles
rays
waves
The process by which plants capture light energy and use it to synthesize carbohydrates is called _____.
photosynthesis
Which of the following are major outputs of the light reactions?

NADPH
carbohydrates
ATP
NADP
photons
NADPH
ATP
Which of the following molecules is produced by photosystem II?

light
oxygen
sugar
water
carbon dioxide
oxygen
In the first phase of the ___ cycle, atmospheric carbon dioxide is fixed into a five carbon sugar.
Calvin
Match the terms to their outcome in the generalized equation for photosynthesis:

H2A - oxidized/reduced

CO2 - oxidized/reduced
H2A - oxidized
CO2 - reduced
Organisms that acquire energy by consuming organic molecules from environment are called _____.
heterotrophs
The two-step process of photosynthesis is conserved across:

heliobacteria
algae
actinobacteria
green plants
cyanobacteria
fungi
algae, green plants, cyanobacteria
Electromagnetic radiation travels as ____ caused by the oscillation of the electric and magnetic fields.
waves
The wavelength of visible light is between:

1-100 nm
545-833 nm
single wavelength
380-740 nm
invisible and visible light
380-740 nm
Carbohydrates are very important to plant cells because they:

a. are structurally reactive and can establish an electrochemical gradient
b. can be used as an energy reserve
c. are implicated in the formation of "biological batteries"
d. form the building blocks for many organic macromolecules
b & d
When a photon of light with the correct amount of energy strikes an electron, it is boosted from a(n) _____ state to a photoexcited state.
unexcited
Wavelengths refers to:

a. the distance between the peaks in a wave pattern
b. the depth between peaks in a wave pattern
c. the height of peaks in a wave pattern
d. the number of peaks in a wave pattern
e. the length of the ascending portion of a waveform
a
When a high energy electron is transferred from P680 to the primary electron acceptor:

a. ATP is generated
b. solar energy is "captured" to do work
c. the reaction center is excited
d. NADPH is generated
b
The role of the reaction center in PSII is to quickly remove the high energy electron from ____ and transfer it to another molecule where it will be more stable.
P680
The G3P produced at the end of the second phase of the Calvin cycle is directly used to:

a. regenerate ribulose bisphosphate
b. make glucose or other carbohydrates
c. donate low energy electrons
d. produce ATP
e. reduce NADP+
a
A granum is a stack of ___ .
thylakoids
In the following generalized equation for photosynthesis, what does "A" represent for photosynthesis in green plants?

carbohydrates
sunlight
water
oxygen
carbon dioxide
oxygen
In photosynthesis, ____ is produced via the reduction of CO2.
glucose
Why does CO2 enter CAM plants at nighttime?

a. because CAM plants contain only mesophyll cells
b. because CAM plants fix carbon dioxide before it enters the leaf during the day
c. because the stomata of CAM plants are only open at night
d. because CAM plants photosynthesize at night
c
During photosynthesis, NADPH is synthesized by:

the Calvin cycle
PSII
PSI
ATP synthase
photosystem I
Which of the following explain why a 3 carbon molecule is reduced to another 3 carbon molecule in phase 2 of the Calvin cycle?

a. because G3P can polymerize more easily
b. because the bonds of G3P store more energy
c. because the bonds in 3GP release energy when broken
d. because the latter 3 carbon molecule is an enzyme
a, b
The G3P produced at the end of phase 2 of the Calvin cycle is used to synthesize ____ and to regenerate the molecule ____ _____.
carbohydrates
ribulose bisphosphate
T/F A molecule that loses an electron is reduced.
false
Green plants uptake two vital reactants of photosynthesis through their roots and stomata, respectively. What are these reactants?
water and carbon dioxide
The fluid-filled region of the chloroplast between the thylakoid membrane and the inner membrane is called:

the granum
the thylakoid lumen
the stroma
the intermembrane space
stroma
In a typical redox reaction, a molecule that becomes _____ is known as the oxidiing agent because it receives one or more ____ from another molecule.
reduced
electrons
Which of the following are membranes found in a chloroplast?

an inner membrane
the lumen membrane
the thylakoid membrane
the outer membrane
the stroma membrane
inner membrane
thylakoid membrane
outer membrane
Light has properties of both a _____ and a ____.
particle
wave
Carotenoids are _____

membranous structures in a chloroplast
photosystems
pigments
gas exchange structures
chlorophyll variants
pigments
Which of the following are used by green plants to absorb light energy?

chlorophyll b
chlorophyll c
xanthophyll b
chloroplast c
chlorophyll a
chlorophyll a & b
The _____ generated in the Calvin cycle are synthesized using carbon dioxide from the atmosphere.
carbohydrates
Carbon atoms found in the sugars made in photosynthesis are ultimately incorporated from ____ ____ molecules from the atmosphere.
carbon dioxide
In a carbon dioxide molecule, why are carbon atoms considered to be "electron poor" while oxygen atoms are "electron rich"?

a. because electrons are not limited to atmospheric molecules
b. because carbon dioxide is a polar molecule
c. carbon is a very electronegative atom
d. oxygen is a very electronegative atom
d
The oxidation of _____ is important in replenishing electrons in P680 after electrons are lost by excitation.
water
The light reactions convert ___ energy into ____ energy stores in covalent bonds.
light
chemical
When a pigment molecule absorbs a photon of light:

a. carbohydrates are synthesized
b. reducing power is generated
c. water is oxidized
d. an electron is boosted to a higher level
e. electrons in photosystem II are replenished
d
In photosynthesis, glucose is produced via the ____ of CO2.
reduction
Which of the following are components of both PSI and PSII?

a. NADP+ reductase
b. an ATP synthase
c. a reaction center
d. a light harvesting complex
c d
When a ____ molecule absorbs a photon of light, an electron is boosted to a higher energy level.
pigment
____ plants only uptake co2 at night because they close their ___ during the day.
cAM
stomata
Gamma rays and radio waves represent two extreme sets of wavelengths on this sale of radiation:

the electromagnetic spectrum
a gamma-radiographic assembly
the visible spectrum
the radiation index
the electromagnetic spectrum
The ____ membrane contains pigment molecules, including chlorophyll.
thylakoid
The pores in the surface of a leaf that can participate in gas exchange are called ____.
stomata
If an excited electron return to its original energy shell within the same atom, the electromagnetic energy originally used to excite the electron may be released as:

light
electrical energy
heat
light
heat
Photosystems I and II are located in:

the stroma
the inner mitochondrial membrane
the thylakoid membrane
the intermembrane space
the thylakoid membrane
During photosynthesis, NADPH is synthesized by:

PSI
ATP synthase
the Calvin cylce
PSII
PSI
P680 replenishes its high energy electron via a low energy electron that the reaction center extracts from ____ .
H20
Light is considered a form of electromagnetic radiation because:

a. it responds to magnetic stimuli
b. light and magnetic waves can bend
c. it is polarized
d. it consists of both electric and magnetic energy
d
Ultraviolet light is more damaging to cells than visible light because:

a. UV light is higher energy than visible light
b. UV light is less abundant than visible light
c. UV light has a shorter wavelength than visible light
d. visible light is not absorbed by most cells, while UV light is
a, c
Carbon dioxide is reduced during the formation of ____ .
G3P
In plants, which of the following is polymerized to form starch?

glyceraldehyde-3-phosphate
sucrose
ribulose biphosphate
glucose
glucose
Several dozen of these kinds of molecules help comprise a light harvesting complex:

ETCs
manganese clusters
pigments
NADP+ reductases
ATP synthases
pigments
The light-harvesting complex is found in the ____ membrane.
thylakoid
Which of the following are components of both PSI and PSII?

an ATP synthase
a reaction center
a light harvesting complex
NADP+ reductase
reaction center
light harvesting complex
The energy that is released as electrons pass from one electron carrier to the next is used to pump ____ into the thylakoid lumen.
protons
In the light reactions, ATP is generated via:

the direct excitation of electrons
chemiosmosis
glycolysis
the Calvin cycle
chemiosmosis
How is an H+ electrochemical gradient established and maintained in photosynthesis?

a. the movement of electrons from PSII to PSI
b. the formation of NADPH
c. the splitting of water
d. the reduction of carbon dioxide
e. the formation of carbohydrates
f. the movement of electrons from PSi and PSII
a, b, c
In the process of photosynthesis, water is oxidized during the formation of ____ .
O2
Which of the following is the source of electrons used to ultimately reduce the C-O bond of PGA?

rubisco
G3p
NADPH
ATP
NADPH
Which of the following produce ATP that could be used in phase 3 of the Calvin cycle?

a. cyclic electron flow
b. phase 1 of the Calvin cycle
c. ATP synthases in the thylakoid membrane
d. photosystem I
e. the light reactions
a, c, e
Ninety percent of the plants of Earth are:

CAM plants
C4 plants
C3 plants
C3 plants
The enzyme rubisco has more than one activities. Because of this, most plants also perform _____, which consumes oxygen and liberates carbon dioxide. This process can lower the net benefit from photosynthesis.
photorespiration
How might a reaction that requires an input of energy proceed?

a. by allowing it to occur under spontaneous circumstances
b. by coupling it to a spontaneous reaction
c. by coupling it to an exergonic reaction
d. by coupling it to an endergonic reaction
b, c
Why might plants contain a variety of pigments?

a. because each pigment is necessary to generate an electromagnetic spectrum
b. because each pigment is ultimately the final electron acceptor for its own ETC
c. because this feature enables plants to absorb light at many different wavelengths
d. because visible light contains only one wavelength on a seasonal basis
c
Rather than releasing energy, an excited electron in a photosynthetic pigment is removed from that molecule and transferred to another molecule where the electron is _____ stable.
more
Why is it significant that energy from excited electrons in photosynthesis is "captured"?

a. because the energy is not released but instead used productively
b. because the energy is actually in the form of carbohydrate
c. because "captured" energy is released as light, which is used to excited other electrons
d. because "captured" energy is released as heat, which is the basis of endothermy
A
Electrons in an _____ state tend to be unstable, and thus must release or channel their energy.
excited
Which of the following produce ATP that could be used in phase 3 of the Calvin cycle?

a. the light reactions
b. ATP synthases in the thylakoid membrane
c. phase 1 of the Calvin cycle
d. Photosystem I
e. cyclic electron flow
a, b, e
Which of the following is the source of electrons used to ultimately reduce the C-O bond of PGA?

G3P
ATP
NADPH
Rubisco
NADPH
After ____ molecules are made, they may be linked together in a polysaccharide called starch.
glucose
A key bond change in the reduction phase of the Calvin cycle in the reduction of the C-____ bond to a C-____ bond.
C-O to a C-hydrogen
T/F: The term "C3" was derived from the 3-carbon sugar that represents the end product of photosynthesis.
False
Which of the following would be an appropriate radioactive tracer for studying the flow of carbon through the Calvin cycle?

radioactive ATP
radioactive sulfur
radioactive CO2
radioactive glucose
CO2
The flow of electrons from PSII to PSI is called _____ electron flow because electrons end up at different destinations.
noncyclic