chpt 10
The light reactions of photosynthesis supply the Calvin cycle with CO2 and ATP. H2O and NADPH. sugar and O2. ATP and NADPH. light energy.
ATP and NADPH
Which of the following occurs during the Calvin cycle? (eText Concept 10.3) Light energy is converted to chemical energy. ATP is oxidized and NADPH is reduced. ATP is reduced and NADPH is oxidized. ATP is hydrolyzed and NADPH is oxidized. Linear electron flow produces the materials required for the fixation of carbon from carbon dioxide.
ATP is hydrolyzed and NADPH is oxidized
Which of the following sequences correctly represents the flow of electrons during photosynthesis? NADPH → electron transport chain → O2 NADPH → O2 → CO2 H2O → NADPH → Calvin cycle NADPH → chlorophyll → Calvin cycle H2O → photosystem I → photosystem II
H2O - NADPH- Calvin cycle
During photosynthesis in chloroplasts, O2 is produced from __________ via a series of reactions associated with __________. (eText Concept 10.2) CO2 ... photosystem II H2O ... photosystem II CO2 ... the Calvin cycle H2O ... photosystem I CO2 ... both photosystem I and the Calvin cycle
H2O ... photosystem II
A photon of which of these colors would carry the most energy? (eText Concept 10.2) green yellow blue orange red
blue
The most important role of pigments in photosynthesis is to __________. (eText Concept 10.2) capture light energy screen out harmful ultraviolet rays store energy catalyze the hydrolysis of water catalyze the synthesis of ATP
blue-violet and red-orange
Which of the following is cycled in the cyclic variation of the light reactions? (eText Concept 10.2) electrons ATP NADPH ribulose bisphosphate protons
electrons
Which of the following groups of organisms contains only heterotrophs? (eText Overview) bacteria protists fungi All of the listed responses are correct. None of the listed responses are correct.
fungi
The light reactions of photosynthesis generate high-energy electrons, which end up in __________ through linear electron flow. The light reactions also produce __________ and __________. (eText Concept 10.2) ATP ... NADPH ... oxygen oxygen ... sugar ... ATP chlorophyll ... ATP ... NADPH water ... sugar ... oxygen NADPH ... ATP ... oxygen
NADPH...ATP...oxygen
You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark? (eText Concept 10.4) Even though it cannot carry out the light reactions, the plant can still produce sugars because the Calvin cycle does not require light. While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation. Even though the plant received no visible light, it was able to use the short-wave part of the electromagnetic spectrum (gamma rays and X-rays) to carry out photosynthesis. When light energy is not available, plants can derive energy from inorganic molecules. None of the listed responses is correct.
while it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation
Of the following, which occurs during the Calvin cycle? (eText Concept 10.3) Light energy is converted to chemical energy. ATP and NADPH are synthesized. CO2 is reduced. Excited electrons are conveyed from chlorophyll to an electron acceptor. Photons are absorbed.
CO2 is reduced
In photosynthesis, plants use carbon from __________ to make sugar and other organic molecules. (eText Overview) water carbon dioxide chlorophyll the sun soil
carbon dioxide
In the Calvin cycle, CO2 is combined with __________. (eText Concept 10.3) a two-carbon compound to form a three-carbon compound a five-carbon compound to form an unstable six-carbon compound, which decomposes into two three-carbon compounds a seven-carbon compound to form two four-carbon compounds a five-carbon compound to form a stable six-carbon compound that can be converted directly to glucose two two-carbon compounds to form a five-carbon compound
a 5 carbon compound to form an unstable six-carbon compound, which decomposes into two 3 carbon compounds
Based on the work of Engelmann, a plot of photosynthetic activity versus wavelength of light is referred to as __________. (eText Concept 10.2) an effective spectrum an absorption spectrum an electromagnetic spectrum a visible light spectrum an action spectrum
action spectrum
Glyceraldehyde-3-phosphate (G3P) is produced in the stroma of chloroplasts. Which of the following statements is most accurate regarding this compound? (eText Concept 10.3) It is produced from glucose during glycolysis. It is a three-carbon sugar. For every three molecules of CO2 reduced in the Calvin cycle, six molecules of G3P are formed but only one of these molecules exits the cycle to be used by the plant cell. For every three molecules of CO2, six molecules of G3P are formed but five molecules must be recycled to regenerate three molecules of RuBP All of the listed responses are correct.
all are correct
The use of non-C3 and non-CAM plants as crops may be limited in some regions because on hot, dry days, they close their stomata. What happens as a result of closing their stomata? (eText Concept 10.4) Water loss is reduced. Carbon dioxide is prevented from entering the leaf. In a process called photorespiration, rubisco binds oxygen instead of carbon dioxide. Oxygen from the light reactions in the leaf builds up. All of the listed responses are correct.
all are correct
Which of the following statements is a correct distinction between autotrophs and heterotrophs? Only heterotrophs require oxygen. Cellular respiration is unique to heterotrophs. Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic. Only heterotrophs require chemical compounds from the environment. Only heterotrophs have mitochondria.
autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic
What is the range of wavelengths of light that are absorbed by the pigments in the thylakoid membranes? (eText Concept 10.2) green, which is why plants are green blue-violet and red-orange the entire spectrum of white light the infrared the range absorbed by carotenoids
capture light energy
You could distinguish a thylakoid membrane from an inner mitochondrial membrane because the thylakoid membrane would __________. (eText Concept 10.2) be inside a mitochondrion function in energy transformation have photosynthetic pigments contain protein but not lipids have all of the listed characteristics
have photosynthetic pigments
How is photosynthesis similar in C4 plants and CAM plants? Both types of plants make most of their sugar in the dark. In both cases, only photosystem I is used. In both cases, thylakoids are not involved in photosynthesis. Both types of plants make sugar without the Calvin cycle. In both cases, rubisco is not used to fix carbon initially.
in both cases, rubisco is not used to fix carbon initially
In photosynthesis, what is the fate of the oxygen atoms present in CO2? They end up __________. (eText Concept 10.1) as molecular oxygen in sugar molecules in water as molecular oxygen and in sugar molecules in sugar molecules and in water
in sugar molecules and in water
What is the role of NADP+ in photosynthesis? (eText Concept 10.1) It helps produce ATP from the light reactions. It absorbs light energy. It forms part of photosystem II. It is the primary electron acceptor. It forms NADPH to be used in the Calvin cycle.
it forms NADPH to be used in the calvin cycle
What is the role of NADP+ in photosynthesis? (eText Concept 10.2) It assists chlorophyll in capturing light. It acts as the primary electron acceptor for the photosystems. As part of the electron transport chain, it manufactures ATP. As a component of photosystem II, it catalyzes the hydrolysis of water. It is reduced and then carries electrons to the Calvin cycle.
it is reduced and then carries electrons to the Calvin cycle
Open Hint for Question 8 in a new window Molecular oxygen is produced during __________. (eText Concept 10.1) glycolysis linear electron flow during the light reactions the Calvin cycle cyclic electron flow during the light reactions re-energization of electrons by PSI
linear electron flow during the light reactions
The energy used to produce ATP in the light reactions of photosynthesis comes from __________. (eText Concept 10.2) the oxidation of sugar molecules splitting water movement of H+ through a membrane carbon fixation fluorescence
movement of H+ through a membrane
In mechanism, photophosphorylation is most similar to the Calvin cycle. substrate-level phosphorylation in glycolysis. carbon fixation. reduction of NADP+. oxidative phosphorylation in cellular respiration.
oxidative phosphorylation in cellular respiration
Which of the following does not occur during the Calvin cycle? consumption of ATP carbon fixation oxidation of NADPH regeneration of the CO2 acceptor release of oxygen
release of oxygen
Which process is most directly driven by light energy? ATP synthesis carbon fixation in the stroma reduction of NADP+ molecules removal of electrons from chlorophyll molecules creation of a pH gradient by pumping protons across the thylakoid membrane
removal of electrons from chlorophyll molecules
During photosynthesis in a eukaryotic cell, an electrochemical gradient is formed across the __________. (eText Concept 10.2) chloroplast outer membrane thylakoid membrane chloroplast inner membrane stomata cristae
stomata
The Calvin cycle occurs in the __________. (eText Concept 10.1) thylakoid membrane thylakoid lumen stroma stomata matrix
stroma
Open Hint for Question 9 in a new window The reactions of the Calvin cycle are NOT directly dependent on light, but they usually do NOT occur at night. Why? (eText Concept 10.1) It is often too cold at night for these reactions to take place. Carbon dioxide concentrations decrease at night. The Calvin cycle requires products only produced when the photosystems are illuminated. Plants usually open their stomata at night. At night, no water is available for the Calvin cycle.
the Calvin cycle requires products only produced when the photosystems are illuminated
Rubisco is __________. (eText Concept 10.3) the enzyme in plants that captures CO2 to begin the Calvin cycle the enzyme responsible for splitting H2O to produce O2 in photosynthesis the enzyme that forms a four-carbon compound in CAM photosynthesis the first stable intermediate in C4 photosynthesis the five-carbon sugar molecule that reacts with CO2 to begin the Calvin cycle
the enzyme in plants that captures CO2 to begin the Calvin cycle
Which of the following statements correctly describes the relationship between the light reactions and the Calvin cycle? (eText Concept 10.3) The light reactions produce carbon dioxide, ATP, and NADPH, all of which are used in the Calvin cycle. The light reactions produce ATP and NADPH, both of which are used in the Calvin cycle. The light reactions produce ADP and NADP+, both of which are used in the Calvin cycle. The light reactions produce water, ATP, and NADPH, all of which are used in the Calvin cycle. The light reactions produce carbon dioxide and water, both of which are used in the Calvin cycle.
the light reactions produce ATP and NADPH, both of which are used in the Calvin cycle
What structure is formed by the reaction center, light-harvesting complexes, and primary electron acceptors that cluster, and is located in the thylakoid membrane? (eText Concept 10.2) the fluorescence center the photosystem the electron transport chain NADP+ reductase ATP synthase
the photosystem
When chloroplast pigments absorb light, __________. (eText Concept 10.2) the pigments become reduced the pigments lose potential energy the pigments' electrons become excited the Calvin cycle is triggered the pignments' photons become excited
the pigments' electrons become excited
How does carbon dioxide enter the leaf? (eText Concept 10.1) through the chloroplasts through the roots through the thylakoids through the stomata through the vascular system
through the stomata
Chlorophyll molecules are in which part of the chloroplast? (eText Concept 10.1) thylakoid membranes stroma stomata plasma membrane thylakoid lumen
thylakoid membranes
In a rosebush, chlorophyll is located in __________. (eText Concept 10.1) chloroplasts, which are in mesophyll cells in the thylakoids of a leaf mesophyll cells, found within the thylakoids of a leaf's chloroplasts thylakoids, which are in mesophyll cells in the chloroplasts of a leaf chloroplasts, which are in thylakoids in the mesophyll cells of a leaf thylakoids, which are in chloroplasts in the mesophyll cells of a leaf
thylakoids, which are in the chloroplasts in the mesophyll cells of a leaf
Why are C4 plants more suited to hot climates than C3 plants? (eText Concept 10.4) They do not close their stomata in hot, dry weather. Unlike C3 plants, they keep fixing carbon dioxide even when the concentration of carbon dioxide in the leaf is low. They evolved in cold weather but migrated to the tropics, where they were more suitable. They suspend photosynthesis in the heat. The same cells that bind carbon dioxide perform the Calvin cycle.
unlike C3 plants, they keep fixing carbon dioxide even when the concentration of carbon dioxide in the leaf is low
Both mitochondria and chloroplasts __________. (eText Concept 10.2) use chemiosmosis to produce ATP obtain electrons from water reduce NAD+, forming NADP release oxygen as a by-product are surrounded by a single membrane
use chemiosmosis to produce ATP
The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from __________. (eText Concept 10.1) carbon dioxide glucose radioisotopes water light
water
Where do the electrons entering photosystem II come from? (eText Concept 10.2) chlorophyll molecules in the antenna complex ATP the electron transport chain light water
water
