Chapter 8

Both mitochondria and chloroplasts _____. 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

a

Chlorophyll molecules are in which part of the chloroplast? thylakoid membranes stroma stomata plasma membrane thylakoid lumen

a

Rubisco is _____. the enzyme in plants that first captures CO2 to begin the Calvin cycle the enzyme responsible for splitting H2O to produce O2 in photosynthesis the enzyme that forms a 4-carbon compound in CAM photosynthesis the first stable intermediate in C4 photosynthesis the 5-carbon sugar molecule that reacts with CO2 to begin the Calvin cycle

a

The most important role of pigments in photosynthesis is to _____. capture light energy screen out harmful ultraviolet rays store energy catalyze the hydrolysis of water catalyze the synthesis of ATP

a

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

a

Which of the following statements is a correct distinction between autotrophs and 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. Only heterotrophs require oxygen. Cellular respiration is unique to heterotrophs.

a

During photosynthesis in a eukaryotic cell, an electrochemical gradient is formed across the ______. chloroplast outer membrane thylakoid membrane chloroplast inner membrane stomata cristae

b

During photosynthesis in chloroplasts, O2 is produced from _____ via a series of reactions associated with _____. CO2 ... photosystem II H2O ... photosystem II CO2 ... the Calvin cycle H2O ... photosystem I CO2 ... both photosystem I and the Calvin cycle

b

In photosynthesis, plants use carbon from _____ to make sugar and other organic molecules. water carbon dioxide chlorophyll the sun soil

b

In the Calvin cycle, CO2 is combined with _____. a 2-carbon compound to form a 3-carbon compound a 5-carbon compound to form an unstable 6-carbon compound, which decomposes into two 3-carbon compounds a 7-carbon compound to form two 4-carbon compounds a 5-carbon compound to form a stable 6-carbon compound that can be converted directly to glucose two 2-carbon compounds to form a 5-carbon compound

b

The light reactions of photosynthesis supply the Calvin cycle with __________. H2O and NADPH ATP and NADPH sugar and O2 light energy CO2 and ATP

b

What is the range of wavelengths of light that are absorbed by the pigments in the thylakoid membranes? 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

b

What structure is formed by the reaction center, light-harvesting complexes, and primary electron acceptors that cluster, and is located in the thylakoid membrane? the fluorescence center the photosystem the electron transport chain NADP+ reductase ATP synthase

b

Which of the following statements correctly describes the relationship between the light reactions and the Calvin cycle? The light reactions produce carbon dioxide, ATP, 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, NADPH, all of which are used in the Calvin cycle. The light reactions produce carbon dioxide and water, all of which are used in the Calvin cycle.

b

Which process is most directly driven by light energy? carbon fixation in the stroma removal of electrons from chlorophyll molecules reduction of NADP+ molecules creation of a pH gradient by pumping protons across the thylakoid membrane ATP synthesis

b

Why are C4 plants more suited to hot climates than C3 plants? 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.

b

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? Even though it can't carry out the light reactions, the plant can still produce sugars because the Calvin cycle doesn't 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.

b

A photon of which of these colors would carry the most energy? green yellow blue orange red

c

Of the following, which occurs during the Calvin cycle? 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.

c

The Calvin cycle occurs in the _____. thylakoid membrane thylakoid lumen stroma stomata matrix

c

The energy used to produce ATP in the light reactions of photosynthesis comes from _____. the oxidation of sugar molecules splitting water movement of H+ through a membrane carbon fixation fluorescence

c

The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why? 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.

c

When chloroplast pigments absorb light, _____. they become reduced they lose potential energy their electrons become excited the Calvin cycle is triggered their photons become excited

c

Which of the following does NOT occur during the Calvin cycle? carbon fixation consumption of ATP release of oxygen oxidation of NADPH regeneration of the CO2 acceptor

c

You could distinguish a granum from a crista because the granum, but not the crista, would _____. be inside a mitochondrion function in energy transformation have photosynthetic pigments contain protein but not lipids Two of the listed responses are correct.

c

During photosynthesis, an electron transport chain is used to _____. transport NADPH from the light reactions to the Calvin cycle transport excited electrons from P700 to an electron acceptor transport excited electrons from P680 to an electron acceptor transport electrons from photosystem II to photosystem I transport excited electrons from P700 to an electron acceptor and transport excited electrons from P680 to an electron acceptor

d

How does carbon dioxide enter the leaf? through the chloroplasts through the roots through the thylakoids through the stomata through the vascular system

d

The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from _____. carbon dioxide glucose radioisotopes water light

d

Based on the work of Engelmann, the wavelengths of light most effective in driving photosynthesis are referred to as _____. an effective spectrum an absorption spectrum an electromagnetic spectrum a visible light spectrum an action spectrum

e

Glyceraldehyde-3-phosphate (G3P) is produced in the stroma of chloroplasts. Which of the following statements is most true about this compound? It is produced from glucose during glycolysis. It is a 3-carbon sugar. For every three molecules of CO2, six molecules of G3P are formed but only one molecule 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.

e

How is photosynthesis similar in C4 plants and CAM plants? Both types of plants make sugar without the Calvin cycle. Both types of plants make most of their sugar in the dark. In both cases, thylakoids are not involved in photosynthesis. In both cases, electron transport is not used. In both cases, rubisco is not used to fix carbon initially.

e

In a rosebush, chlorophyll is located in _____. 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

e

In mechanism, photophosphorylation is most similar to __________. substrate-level phosphorylation in glycolysis reduction of NADP+ the Calvin cycle carbon fixation oxidative phosphorylation in cellular respiration

e

In photosynthesis, what is the fate of the oxygen atoms present in CO2? They end up _____. as molecular oxygen in sugar molecules in water as molecular oxygen and in sugar molecules in sugar molecules and in water

e

The light reactions of photosynthesis generate high-energy electrons, which end up in _____. The light reactions also produce _____ and _____. ATP ... NADPH ... oxygen oxygen ... sugar ... ATP chlorophyll ... ATP ... NADPH water ... sugar ... oxygen NADPH ... ATP ... oxygen

e

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? It reduces water loss. It prevents carbon dioxide from entering the leaf. In a process called photorespiration, rubisco binds oxygen instead of carbon dioxide. It builds up oxygen from the light reactions in the leaf. All of the listed responses are correct.

e

What is the role of NADP+ in photosynthesis? 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.

e

What is the role of NADP+ in photosynthesis? 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.

e

Where do the electrons entering photosystem II come from? chlorophyll molecules in the antenna complex ATP the electron transport chain light water

e