General Biology I - Chapter 8: Photosynthesis

A thylakoid that is placed in a basic solution will synthesize ATP. How is this possible? A proton gradient is created by the difference in pH. An electron gradient is created by the difference in pH. ATP is formed spontaneously at low pH. The carbon reactions are blocked in the thylakoid at high pH. ATP cannot be broken down at low pH.

A proton gradient is created by the difference in pH.

Energy is carried from the light reaction to the carbon reaction by __________. ATP NADPH NADP+ oxygen water

ATP

The purpose of the light reaction is to produce ____. ATP and NADP+ CO2 and ATP ATP and NADPH O2, ATP, and NADP+ O2, ATP, and NADPH

ATP and NADPH

What is the main role of the pigment molecules within the antenna or light-harvesting complex? Oxidize water and release oxygen to the reaction center chlorophyll. Absorb photons and transfer light energy to the reaction center chlorophyll. Synthesize NADPH. Pass electrons to the electron transport chain and then to NADPH. Increase H+ concentration in the stroma.

Absorb photons and transfer light energy to the reaction center chlorophyll.

Plants require a lot of water for transpiration, metabolism, and photosynthesis. How is water used in photosynthesis? As an electron donor As an electron acceptor To combine with ADP forming ATP To combine with NADP+ to form NADPH As a substrate for ATP synthase

As an electron donor

The primary advantage C4 plants have over C3 plants is that C4 plants minimize photorespiration compared with C3 plants. C4 plants can produce sugars more efficiently than C3 plants under cool, wet conditions. C4 plants can produce CO2 needed for sugar production in the Calvin cycle more efficiently than C3 plants. relative to C3 plants, C4 plants can keep their stomata open more frequently to limit water evaporation.

C4 plants minimize photorespiration compared with C3 plants.

The rate of photosynthesis is much greater in green light than red light. True False

False

Which of the following represents a reactant in the light reaction of photosynthesis? oxygen carbon dioxide ATP NADPH H2O

H2O

________ consume organic molecules to live. Photoautotrophs Autotrophs Hemitrophs Heterotrophs Plants

Heterotrophs

A green plant is first grown in blue light and then in green light. The likely outcome for photosynthesis in both phases is Increased plant growth in blue light and no plant growth in green light. No plant growth in blue light and increased plant growth in green light. Decreased plant growth in blue light and no plant growth in green light. No plant growth in blue light and decreased plant growth in green light.

Increased plant growth in blue light and no plant growth in green light.

What would happen to a plant that is treated with a chemical that prevents electrons from moving through the electron transport chain? It could not produce NADP+. It could no longer produce CO2. It could not generate an electrochemical H+ gradient across a membrane. Water would be broken down to form oxygen at a higher rate to compensate. More electrons would be available for the light harvesting array.

It could not generate an electrochemical H+ gradient across a membrane.

What will happen to the pH inside a thylakoid that is exposed to light? It will decrease It will increase It will not change

It will decrease

The molecules that directly convert NADP+ to NADPH is/are ferredoxin. cytochrome complex. NADP reductase. plastocyanin. RUBISCO.

NADP reductase.

Products of the Calvin cycle include: Check all that apply. NADP+ Pi ADP glyceraldehyde-3-phosphate (G3P) NADPH

NADP+ Pi ADP glyceraldehyde-3-phosphate (G3P)

Which molecules used during the Calvin cycle could be used by a cell in a reduction reaction? NADPH NADP+ ATP H+ Water

NADPH

The purpose of the light reaction is to produce ____. NADPH and ATP ATP and oxygen oxygen and glucose carbon dioxide and ATP glucose and NADPH

NADPH and ATP

In the reaction, 6CO2 + 6H2O →C6H12O6 + 6O2, which side should energy be placed on? The left side, this is an endergonic reaction. The left side, this is an exergonic reaction. The right side, this is an endergonic reaction. The right side, this is an exergonic reaction. Neither side, the reaction is in equilibrium.

The left side, this is an endergonic reaction.

A comparison of mitochondria and chloroplast shows that they have very different electron transport protein complexes. only mitochondria contain ATP synthase. both generate ATP via a H+ electrochemical gradient. both use an increase in pH in their inner-membrane space to produce ATP. both use oxygen as a final electron acceptor.

both generate ATP via a H+ electrochemical gradient.

Which portion of the photosynthetic apparatus absorbs light? photosystem I photosystem II NADP reductase both photosystem I and photosystem II both photosystem I and NADP reductase

both photosystem I and photosystem II

When NADPH _____ electrons in the Calvin cycle it is ______, forming NADP+. donates, oxidized accepts, reduced accepts, oxidized donates, reduced donates, hydrolyzed

donates, oxidized

NADPH is produced by light reactions alone. the Calvin cycle alone. both light reactions and the Calvin cycle. neither the light reactions nor the Calvin cycle. NADPH production is not a part of photosynthesis.

light reactions alone.

Blue light has ___ energy than red light and is ____ by a green leaf. more, absorbed less, absorbed more, reflected less, reflected

more, absorbed

A plant performing photosynthesis will produce ____ and consume _____. oxygen, carbon dioxide oxygen, water water, carbon dioxide carbon dioxide, oxygen carbon dioxide, water

oxygen, carbon dioxide

The organisms that most specifically utilize light energy to make organic molecules from inorganic molecules are photoautotrophs. photoheterotrophs. photoautotrophs. photoheterotrophs. heterotrophs.

photoautotrophs.

The equation, 6CO2 + 6H2O →C6H12O6 + 6O2, describes which of the following processes? photosynthesis light reaction Calvin cycle nitrogen fixation aerobic respiration

photosynthesis

Succulent plants such as cacti or pineapple are C3 plants. are highly efficient at photosynthesis in cooler and wet environments. tend to undergo substantial rates of photorespiration. produce 4-carbon malate in the first step of carbon fixation. continually produce sugar, both day and night under hot, arid conditions.

produce 4-carbon malate in the first step of carbon fixation.

Mutation of molecules in photosystem I but not photosystem II would lead a plant cell to produce ATP and NADP+ produce CO2 and ATP produce ATP and NADPH produce O2, ATP, and NADP+ produce O2, ATP, and NADPH

produce O2, ATP, and NADP+

The process that forms the electrochemical gradient during photosynthesis is the hydrolysis of ATP. production of water from oxygen in the thylakoid lumen. production of H+ in the stroma during NADPH production. pumping of H+ into the thylakoid lumen. movement of water by osmosis.

pumping of H+ into the thylakoid lumen.

In the reaction, 6CO2 + 6H2O →C6H12O6 + 6O2, carbon dioxide is being ____. reduced oxidized phosphorylated hydrolyzed condensed

reduced

Using 14CO2 as a radioactive tracer, which molecule would be the last to incorporate 14C within the Calvin cycle? glyceraldehyde-3-phosphate (G3P) 1,3-biphosphoglycerate (1,3-BPG) 3-phosphoglycerate (3PG) ribulose biphosphate (RuBP) rubisco

ribulose biphosphate (RuBP)

CO2 binds to ____ in the Calvin cycle. ribulose bisphosphate glucose water photosystem II NADPH

ribulose bisphosphate

A plant becomes dried out when stomata close, decreasing gas exchange. stomata open, decreasing gas exchange. stomata close, increasing gas exchange. stomata open, increasing gas exchange.

stomata close, decreasing gas exchange.

The main structure for gas exchange in plants is called the mesophyll. chloroplast. stomata. epidermis. root.

stomata.

Photorespiration tends to occur under dry and hot conditions. uses a 3-carbon sugar precursor to produce oxygen. requires CO2. occurs in C4 plants. uses the enzyme PEP carboxylase rather than rubisco to produce 3-phosphoglycerate.

tends to occur under dry and hot conditions.

Both ATP and NADPH are required for electron transport through the thylakoid membrane. the light reaction only. the Calvin cycle only. both the light reaction and Calvin cycle. neither the light reaction nor the Calvin cycle.

the Calvin cycle only.

The ultimate source of energy for reactions in a plant is ____. glucose. glycogen. plants. the sun. catabolism.

the sun.

Photons from light can boost an electron to a higher energy state. True False

true

If you wanted to install lights to grow plants indoors, the type of light would you want to us is ultraviolet, because it has ionizing wavelengths. gamma rays, because it has ionizing wavelengths. visible light, because it has non-ionizing wavelengths. microwaves, because it has non-ionizing wavelengths. infrared, because it has ionizing wavelengths.

visible light, because it has non-ionizing wavelengths.

If a C3 plant that normally closes its stomata during hot, dry conditions were triggered to open them instead, the most likely outcome would be that O2 enters the leaf, increasing the rate of photosynthesis. water leaves the leaf, decreasing the rate of photosynthesis. CO2 enters the leaf, decreasing the rate of photosynthesis. glucose leaves the leaf, increasing the rate of photosynthesis. more chlorophyll is made, increasing the rate of photosynthesis.

water leaves the leaf, decreasing the rate of photosynthesis.

A new flower species has a unique photosynthetic pigment. The leaves of this plant appear to be blue-green. What wavelengths of visible light does this pigment reflect? red and yellow blue and violet green and blue red, yellow, and green green, red, and violet

green and blue

A C4 plant minimizes photorespiration by having the light reactions and carbon reactions occur in different cells, so oxygen does not come into contact with rubisco. having the light reactions and carbon reactions occur in different cells, so carbon dioxide does not come into contact with rubisco. stomata that are only opened at night, storing carbon dioxide in malate, and releasing carbon dioxide during the day. stomata that are only opened at night, storing oxygen in malate, and releasing oxygen during the day.

having the light reactions and carbon reactions occur in different cells, so oxygen does not come into contact with rubisco.

CAM (crassulacean acid metabolism) plants such as cacti differ from standard C4 plants such as corn in which of the following ways? CAM plants minimize photorespiration whereas C4 plants do not. CAM plants use both mesophyll and bundle sheath leaf cells for photosynthesis whereas C4 plants do not. CAM plants are more efficient at producing sugar than C4 plants regardless of environmental conditions. CAM plants produce a 4-carbon molecule in the first step of carbon fixation, but C4 plants do not. CAM plants are limited to producing CO2 for the Calvin cycle during the day, while C4 plants produce CO2 for the Calvin cycle both during the day and at night.

CAM plants are limited to producing CO2 for the Calvin cycle during the day, while C4 plants produce CO2 for the Calvin cycle both during the day and at night.

Molecules that are required for the Calvin cycle include: Check all that apply. H2O. CO2. NADPH. rubisco. ATP.

CO2. NADPH. rubisco. ATP.

How might a plant cope with the fact that the Calvin cycle uses more ATP than NADPH, yet produces roughly the same amount of both energy intermediates in photosystems I and II? Photosynthesis can revert from a noncyclic to cyclic electron flow, producing more ATP than NADPH. More pigment can be rapidly created for greater photosynthetic capacity, producing equal amounts of ATP and NADPH. Plants often increase the amount of NADP reductase, thereby increasing NADPH production to match ATP output. Electron flow rate can be increased, increasing both ATP and NADPH production. Increase the electrochemical gradient for H+ across the thylakoid membrane, producing more ATP but not NADPH.

Photosynthesis can revert from a noncyclic to cyclic electron flow, producing more ATP than NADPH.

When Calvin injected 14C labeled CO2 into cultures of green algae, what led him to conclude that rubisco adds CO2 to ribulose bisphosphate in the Calvin cycle? Radioactivity first appeared in 3-phosphoglycerate Radioactivity first appeared in glucose Radioactivity first appeared in ribulose bisphosphate Radioactivity appeared last in ribulose bisphosphate Radioactivity appeared last in glucose Radioactivity appeared last in 3-phosphoglycerate

Radioactivity appeared last in ribulose bisphosphate

When Calvin injected 14C labeled CO2 into cultures of green algae, which of the following was observed because the molecule accepting the CO2 was unstable? Radioactivity first appeared in 3-phosphoglycerate Radioactivity first appeared in glucose Radioactivity first appeared in ribulose bisphosphate Radioactivity appeared last in ribulose bisphosphate Radioactivity appeared last in glucose Radioactivity appeared last in 3-phosphoglycerate

Radioactivity first appeared in 3-phosphoglycerate

When NADP+ _____ electrons in the light reaction it is ______ forming NADPH. accepts, reduced accepts, oxidized donates, reduced donates, oxidized donates, hydrolyzed

accepts, reduced

The pigment responsible for the red-yellow coloration seen in leaves during the color change in autumn is chlorophyll a. chlorophyll b. carotenoid. porphyrin. phytol.

carotenoid.

In which organelle of the plant does photosynthesis takes place? mesophyll chloroplast thylakoid membrane grana mitochondria

chloroplast

Where does the Calvin cycle occur? chloroplast inner membrane thylakoid membrane thylakoid lumen chloroplast stroma chloroplast outer membrane

chloroplast stroma

Harnessing light and splitting water occurs in both photosystem I and II. True False

false

In hot and arid environments, plants that maximize photorespiration produce the most sugars. True False

false

The Calvin cycle is only capable of fixing carbon dioxide in the dark. True False

false