Transcript File - jj-sct

CAMPBELL
BIOLOGY
TENTH
EDITION
Reece • Urry • Cain • Wasserman • Minorsky • Jackson
10
Photosythesis
Clicker Questions by
Scott Meissner
© 2014 Pearson Education, Inc.
Which of the following is a correct explanation for how carbons in
a triose-phosphate can be said to be in a more reduced state
than carbons in carbon dioxide? (See image on next slide.)
a) Carbons in triose-phosphates have accepted more electrons,
and have taken on a full negative charge, relative to carbons
in carbon dioxide.
b) Carbons in triose-phosphate have more bonds with
hydrogen and fewer bonds with oxygen relative to carbons
in carbon dioxide.
c)
Converting carbon in carbon dioxide into carbon in triosephosphate is an endergonic process.
d) Carbons in carbon dioxide donate their excess electrons to
NADP as they are converted to carbons in triose-phosphate.
e) The binding with a phosphate by the triose-phosphate makes
it higher in energy relative to carbons in carbon dioxide.
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
Which of the following is a correct explanation for how carbons in
a triose-phosphate can be said to be in a more reduced state
than carbons in carbon dioxide is?
a) Carbons in triose-phosphates have accepted more electrons,
and have taken on a full negative charge, relative to carbons
in carbon dioxide.
b) Carbons in triose-phosphate have more bonds with
hydrogen and fewer bonds with oxygen relative to carbons
in carbon dioxide.
c)
Converting carbon in carbon dioxide into carbon in triosephosphate is an endergonic process.
d) Carbons in carbon dioxide donate their excess electrons to
NADP as they are converted to carbons in triose-phosphate.
e) The binding with a phosphate by the triose-phosphate makes
it higher in energy relative to carbons in carbon dioxide.
© 2014 Pearson Education, Inc.
Which of the following INCORRECTLY matches a process with
its typical location?
a) Oxygen gas is produced—the soluble space surrounded by
the thylakoid membranes
b) Activated chlorophyll donates an electron—in the thylakoid
membranes
c)
NADPH is oxidized to NADP—the stroma of the chloroplast
d) ATP is produced—the space
between the two chloroplast
envelope membranes
e) RUBISCO catalyzes carbon
fixation—the stroma of the
chloroplast
© 2014 Pearson Education, Inc.
Which of the following INCORRECTLY matches a process with
its typical location?
a) Oxygen gas is produced—the soluble space surrounded by
the thylakoid membranes
b) Activated chlorophyll donates an electron— in the thylakoid
membranes
c)
NADPH is oxidized to NADP—the stroma of the chloroplast
d) ATP is produced—the space
between the two chloroplast
envelope membranes
e) RUBISCO catalyzes carbon
fixation—the stroma of the
chloroplast
© 2014 Pearson Education, Inc.
Of the following events from the light reactions of
photosynthesis, which would be expected to occur first?
a) Light-induced reduction of the primary electron
acceptor in the reaction center of PS II takes place.
b) While being split, electrons are taken out of water.
c) donation of electrons from reduced Pq to the cytochrome
complex
d) acceptance of electrons by Pc from the cytochrome
complex
e) Pq gets electrons
from the reduced
primary electron
acceptor of PS II.
© 2014 Pearson Education, Inc.
Of the following events from the light reactions of
photosynthesis, which would be expected to occur first?
a) Light-induced reduction of the primary electron
acceptor in the reaction center of PS II takes place.
b) While being split, electrons are taken out of water.
c) donation of electrons from reduced Pq to the cytochrome
complex
d) acceptance of electrons by Pc from the cytochrome
complex
e) Pq gets electrons
from the reduced
primary electron
acceptor of PS II.
© 2014 Pearson Education, Inc.
When donating its activated electron, the chlorophyll in
photosystem II (P680) is said to be a very powerful
oxidizing agent. This is best shown by its ability to
a) make use of a proton electrochemical gradient to
drive the formation of ATP.
b) force the oxidation of oxygen in water to oxygen
gas.
c) donate an electron to plastoquinone (Pq).
d) absorb light energy to power redox reactions.
e) force the reduction of NADP+ to NADPH.
© 2014 Pearson Education, Inc.
When donating its activated electron, the chlorophyll in
photosystem II (P680) is said to be a very powerful
oxidizing agent. This is best shown by its ability to
a) make use of a proton electrochemical gradient to
drive the formation of ATP.
b) force the oxidation of oxygen in water to oxygen
gas.
c) donate an electron to plastoquinone (Pq).
d) absorb light energy to power redox reactions.
e) force the reduction of NADP to NADPH.
© 2014 Pearson Education, Inc.
One good reason for carrying out the production of oxygen gas
(O2) in the space surrounded by the thylakoid membranes, and
not in the stroma of the chloroplasts, is
a) that this makes it easier for O2 to exit the chloroplast.
b) that the hydrogen ions released can contribute to the H
electrochemical gradient being generated.
c)
to reduce the concentration of O2 in the stroma so that
organic matter located there is not oxidized by it.
d) that the concentration of water in this space is high, making it
easier to form O2 from the water.
e) that carrying out this process in the
stroma would tend to dry out
this compartment and denature
the enzymes of the Calvin cycle
located there.
© 2014 Pearson Education, Inc.
One good reason for carrying out the production of oxygen gas
(O2) in the space surrounded by the thylakoid membranes, and
not in the stroma of the chloroplasts, is:
a) that this makes it easier for O2 to exit the chloroplast.
b) that the hydrogen ions released can contribute to the H
electrochemical gradient being generated.
c)
to reduce the concentration of O2 in the stroma so that
organic matter located there is not oxidized by it.
d) the concentration of water in this space is high, making it
easier to form O2 from the water.
e) carrying out this process in the
stroma would tend to dry out
this compartment and denature
the enzymes of the Calvin cycle
located there.
© 2014 Pearson Education, Inc.
Which makes an INCORRECT comparison between the
membrane and surrounding compartments indicated in
mitochondria and chloroplasts by the boxes (see figure)?
a) The darker compartment will often be more positively
charged and more acidic.
b) The flow of electrons between items in the membrane
results in protons being pumped from the darker to the
lighter compartments.
c) The lighter compartment is where much of the carbon
metabolism is done.
d) This membrane has an ATP synthase in it.
e) The lighter compartments are
both similar to the cytosolic
compartment of bacteria.
© 2014 Pearson Education, Inc.
Which makes an INCORRECT comparison between the
membrane and surrounding compartments indicated in
mitochondria and chloroplasts by the boxes (see figure)?
a) The darker compartment will often be more positively
charged and more acidic.
b) The flow of electrons between items in the membrane
results in protons being pumped from the darker to
the lighter compartments.
c) The lighter compartment is where much of the carbon
metabolism is done.
d) This membrane has an ATP synthase in it.
e) The lighter compartments are
both similar to the cytosolic
compartment of bacteria.
© 2014 Pearson Education, Inc.
The net reactions for some aerobic respiratory processes in mitochondria, and
for some reactions of photosynthesis in the chloroplast are given below.
Pyruvate import and the Citric acid cycle:
Pyruvic acid + FAD + 4NAD+ + ADP + Pi ÷ 3CO2 + FADH2 + 4NADH + 4H++ ATP
The Calvin cycle:
3CO2 + 9ATP + 5H2O + 6NADPH  Glyceraldehyde 3-phosphate + 9ADP + 8Pi + 6NADP+ + 3H+
The following are descriptions of proposed similarities between these two sets
of reactions. Which is FALSE?
a)
Both alter the redox state of carbons.
b)
Both take place in a soluble space that is homologous to a
bacterial cytoplasmic space.
c)
Both involve a three carbon organic acid, either as a substrate
or as a product.
d)
Both couple very exergonic reactions to drive forward endergonic
reactions of smaller net magnitude.
e)
Both involve various types of nucleic acids in the exchange of
hydrogens.
© 2014 Pearson Education, Inc.
The net reactions for some aerobic respiratory processes in mitochondria, and
for some reactions of photosynthesis in the chloroplast are given below.
Pyruvate import and the Citric acid cycle:
Pyruvic acid + FAD + 4NAD+ + ADP + Pi ÷ 3CO2 + FADH2 + 4NADH + 4H++ ATP
The Calvin cycle:
3CO2 + 9ATP + 5H2O + 6NADPH  Glyceraldehyde 3-phosphate + 9ADP + 8Pi + 6NADP+ + 3H+
The following are descriptions of proposed similarities between these two sets
of reactions. Which is FALSE?
a)
Both alter the redox state of carbons.
b)
Both take place in a soluble space that is homologous to a
bacterial cytoplasmic space.
c)
Both involve a three carbon organic acid, either as a substrate
or as a product.
d)
Both couple very exergonic reactions to drive forward endergonic
reactions of smaller net magnitude.
e)
Both involve various types of nucleic acids in the exchange of
hydrogens.
© 2014 Pearson Education, Inc.
The enzyme rubisco catalyzes the fixation of carbon (see
reaction on next slide). Considering all the carbons
involved, is the production of 3-PGA a net oxidation,
reduction, or neither, and why?
a) Oxidation. Adding a carbon dioxide makes the products
more oxidized.
b) Reduction. Adding the hydrogens from the water results
in a more reduced condition.
c) Reduction. The carbon in the carbon dioxide has been
slightly reduced.
d) Neither. There is no change in the total C–O and C–H
bonds between the products and reactants.
e) Oxidation. The RuBP acts as oxidizing agent in this
reaction.
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
The enzyme rubisco catalyzes the fixation of carbon (see
reaction on next slide). Considering all the carbons
involved, is the production of 3-PGA a net oxidation,
reduction, or neither, and why?
a) Oxidation. Adding a carbon dioxide makes the products
more oxidized.
b) Reduction. Adding the hydrogens from the water results
in a more reduced condition.
c) Reduction. The carbon in the carbon dioxide has been
slightly reduced.
d) Neither. There is no change in the total C–O and C–H
bonds between the products and reactants.
e) Oxidation. The RuBP acts as oxidizing agent in this
reaction.
© 2014 Pearson Education, Inc.
One way in which photosynthesis as done in a typical
C4 plant differs from that in a C3 plant, is that the C4
plant
a) does not produce any oxygen gas at all.
b) actively pumps oxygen gas away from the cells
that contain rubisco.
c) avoids the use of rubisco entirely; instead,
it uses PEP carboxylase to catalyze all carbon
fixation.
d) keeps its stomata more open, so that
more CO2 can enter the plant.
e) carries out the Calvin cycle only in the
chloroplasts of bundle-sheath cells.
© 2014 Pearson Education, Inc.
One way in which photosynthesis as done in a typical
C4 plant differs from that in a C3 plant, is that the C4
plant
a) does not produce any oxygen gas at all.
b) actively pumps oxygen gas away from the cells
that contain rubisco.
c) avoids the use of rubisco entirely; instead,
it uses PEP carboxylase to catalyze all carbon
fixation.
d) keeps its stomata more open, so that
more CO2 can enter the plant.
e) carries out the Calvin cycle only in the
chloroplasts of bundle-sheath cells.
© 2014 Pearson Education, Inc.
In CAM plants, CO2 is
a) temporarily fixed in phloem cells and later
permanently fixed in the bundle-sheath cells.
b) mainly obtained from oxidative respiratory
processes.
c) temporarily fixed at night and later permanently fixed
during the day.
d) fixed into organic matter just by the action of the
enzyme rubisco.
e) brought up to the leaves through air spaces in the
stem so that the stomata of the leaves can be kept
shut to prevent water loss.
© 2014 Pearson Education, Inc.
In CAM plants, CO2 is
a) temporarily fixed in phloem cells and later
permanently fixed in the bundle-sheath cells.
b) mainly obtained from oxidative respiratory
processes.
c) temporarily fixed at night and later permanently
fixed during the day.
d) fixed into organic matter just by the action of the
enzyme rubisco.
e) brought up to the leaves through air spaces in the
stem so that the stomata of the leaves can be kept
shut to prevent water loss.
© 2014 Pearson Education, Inc.