Why are there several structurally different pigments in the reaction centers of photosystems?

1. They enable the reaction center to excite electrons to a higher energy level.
2. Excited electrons must pass through several pigments before they can be transferred to electron acceptors of the electron transport chain.
3. This arrangement enables the plant to absorb light energy of a variety of wavelengths.
4. They enable the plant to absorb more photons from light energy, all of which are at the same wavelength.

c

A flask containing photosynthetic green algae and a control flask containing water with no algae are both placed under a bank of lights, which are set to cycle between 12 hours of light and 12 hours of dark. The dissolved oxygen concentrations in both flasks are monitored. Predict what the relative dissolved oxygen concentrations will be in the flask with algae compared to the control flask. The dissolved oxygen in the flask with algae will _____.

1. always be lower
2. be higher in the light, but lower in the dark
3. be higher in the light, but the same in the dark
4. always be higher

b

Before photosynthetic organisms evolved, ________ was rare in Earth's atmosphere.

1. H2
2. O2
3. CO2
4. H2O
5. N2

b

If photosynthesizing green algae are provided with CO2 containing heavy oxygen (18O), later analysis will show that all of the following molecules produced by the algae contain 18O EXCEPT _____.

1. glucose
2. O2
3. ribulose bisphosphate (RuBP)
4. glyceraldehyde 3-phosphate (G3P)

b

Which of the following are directly associated with photosystem I?

1. receiving electrons from the thylakoid membrane electron transport chain
2. extraction of hydrogen electrons from the splitting of water
3. passing electrons to the cytochrome complex
4. generation of molecular oxygen

a

Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light. An outcome of Engelmann's experiment was to help determine the relationship between _____.

1. wavelengths of light and the rate of aerobic respiration
2. wavelengths of light and the rate of photosynthesis
3. the concentration of carbon dioxide and the rate of photosynthesis
4. wavelengths of light and the amount of heat released

b

Halobacterium has a photosynthetic membrane that appears purple. Its photosynthetic action spectrum is the inverse of the action spectrum for green plants. (That is, the Halobacterium action spectrum has a peak where the green plant action spectrum has a trough.) What wavelengths of light do the Halobacterium photosynthetic pigments absorb?

1. green and yellow
2. blue, green, and red
3. blue and red
4. red and yellow

a

Which of the following occurs during the light-independent reactions of photosynthesis?

1. Chlorophyll captures light energy.
2. NADPH is produced.
3. Water is split apart.
4. Carbon dioxide is converted into sugars.
5. ATP is produced.

d

C3 plants are adapted to ________ environmental conditions, whereas C4 plants are adapted to ________ conditions.

1. drought; rainy
2. temperate; cool and rainy
3. high light; low light
4. dry; wet
5. wet; dry

e

Light-dependent photosynthetic reactions produce:

1. ATP, NADPH, H2O.
2. glucose, ATP, O2.
3. ATP, NADPH, CO2.
4. glucose, ATP, CO2.
5. ATP, NADPH, O2.

e

Use your knowledge of the mechanism of photosynthesis and the data presented in the chart to determine which of the statements below is a correct explanation for the student's data.

1. Cup 3 had the same rate of photosynthesis as Cup 1 because they had the same ratio of disks floating to wattage of light.
2. Cup 4 had the slowest rate of photosynthesis because it had the least baking soda.
3. Cup 2 had the highest rate of photosynthesis because 5 disks were floating at the end of 10 minutes using a 50 watt light bulb.
4. Cup 1 had a low rate of photosynthesis because 0.5 grams of baking soda did not provide a sufficient amount of CO2.

b

The figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?

1. Other pigments absorb light in addition to chlorophyll a.
2. Oxygen given off during photosynthesis interferes with the absorption of light.
3. Green and yellow wavelengths inhibit the absorption of red and blue wavelengths.
4. Aerobic bacteria take up oxygen, which changes the measurement of the rate of photosynthesis.

a

Which of the following provides O2 as an end product?

1. carbon fixation
2. photorespiration
3. light-dependent reactions
4. G3P production
5. light-independent reactions

c

Photosynthetic glucose production requires

1. sunlight.
2. that the concentration of O2 must be significantly higher than that of CO2.
3. that there must be very little water available.
4. ADP.
5. products of the light-dependent reactions

e

The alternative pathways of photosynthesis using the C4 or CAM systems are said to be compromises. Why?

1. CAM plants allow more water loss, while C4 plants allow less CO2 into the plant.
2. Both minimize photorespiration but expend more ATP during carbon fixation.
3. Each one minimizes both water loss and rate of photosynthesis.
4. C4 compromises on water loss and CAM compromises on photorespiration

b

Light-dependent photosynthetic reactions produce:

1. ATP, NADPH, H2O.
2. glucose, ATP, O2.
3. ATP, NADPH, CO2.
4. glucose, ATP, CO2.
5. ATP, NADPH, O2.

e

In autotrophic bacteria, where is chlorophyll located?

1. in the infolded plasma membrane
2. in the nucleoid
3. in the ribosomes
4. in chloroplast membranes

a

How many molecules of CO2 are fixed to form one molecule of glucose?

1. 6
2. 9
3. 12
4. 3
5. 2

a

In photosynthesis, light energy is absorbed by:

1. chlorophyll.
2. carotenoids.
3. RuBP.
4. A and B are correct.
5. A, B, and C are correct.

d

Using the scenario provided, answer the following questions. Carbon dioxide in our atmosphere is a "greenhouse gas." It traps heat at the Earth's surface much like a blanket traps heat at your skin. In the distant past, the long-term average global temperature was warmer than it is today. When the remains of dead plants decomposed, carbon dioxide was returned to the atmosphere and helped to maintain high temperature. However, with the formation of fossil fuels in the Earth's crust from the remains of ancient plants, the average global temperature dropped. At the present time, however, the average global temperature has been slowly increasing in what has been termed "global warming." Use this information, and your understanding of the processes of cellular respiration and photosynthesis, to answer these questions. Why would the formation of fossil fuels result in global cooling?

1. The formation of fossil fuels involved the production of oxygen, which stimulated photosynthesis and plant growth, resulting in greater shade cover.
2. The energy used in fossil fuel formation was converted to heat, which radiated away from the Earth and resulted in its cooling.
3. The formation of fossil fuels involved the depletion of carbon dioxide, which stimulated photosynthesis and plant growth, resulting in greater shade cover.
4. Carbon dioxide fixed by plants was not returned to the atmosphere but retained in plant remains.
5. The formation of fossil fuels involved the production of water, cooling the atmosphere.

d

The term cycle is used to describe the Calvin-Benson (C3) cycle because:

1. the process depends on products from the light-dependent reactions.
2. glucose is made during the process.
3. the process begins and ends with RuBP.
4. CO2 is recycled.
5. the same carbon atoms are reused every time.

c

Photosynthetic organisms include plants:

1. and animals.
2. and fungi.
3. fungi, and algae.
4. fungi, and many single-celled species.
5. algae, and many single-celled species.

e

As represented by the large arrow coming in from the top of Figure 06-02, what molecule(s) enter(s) into the process on the right side of the figure?

1. H2O
2. H2O and O2
3. O2
4. O2 and CO2
5. CO2

e

When water supplies are plentiful for a plant:

1. the stomata remain open.
2. the light-independent reactions will occur more quickly.
3. CO2 uptake will decrease.
4. O2 uptake will increase.
5. the light-dependent reactions are limited.

a

In the thylakoid membranes, the pigment molecules in a light-harvesting complex _____.

1. synthesize ATP from ADP and i
2. transfer electrons to ferredoxin and then NADPH
3. split water and release oxygen from the reaction-center chlorophyll
4. absorb and transfer light energy to the reaction-center chlorophyll

d

The replacement electrons for the reaction center of photosystem I come from:

1. NADPH.
2. H2O.
3. glucose.
4. O2.
5. photosystem II.

e

What would be the expected effect on plants if the atmospheric CO2 concentration was doubled?

1. C4 plants would have faster growth; C3 plants would be minimally affected.
2. C3 plants would have faster growth; C4 plants would have slower growth.
3. All plants would experience increased rates of photosynthesis.
4. C3 plants would have faster growth; C4 plants would be minimally affected.

d

What structural feature of a leaf allows CO2 from the air to enter the leaf?

1. chloroplast
2. mesophyll
3. stomata
4. chlorophyll
5. bundle sheath cells

c

Every ecosystem must have _____.

1. autotrophs and heterotrophs
2. producers and primary consumers
3. autotrophs
4. photosynthesizers

c

The electron transport system associated with photosystem II generates

1. ATP.
2. O2
3. C6H12O6.
4. CO2.
5. NADPH.

a

The accumulation of free oxygen in Earth's atmosphere began with the origin of _____.

1. life and respiratory metabolism
2. chloroplasts in photosynthetic eukaryotic algae
3. land plants
4. cyanobacteria using photosystem II

d

Using the scenario provided, answer the following questions. Carbon dioxide in our atmosphere is a "greenhouse gas." It traps heat at the Earth's surface much like a blanket traps heat at your skin. In the distant past, the long-term average global temperature was warmer than it is today. When the remains of dead plants decomposed, carbon dioxide was returned to the atmosphere and helped to maintain high temperature. However, with the formation of fossil fuels in the Earth's crust from the remains of ancient plants, the average global temperature dropped. At the present time, however, the average global temperature has been slowly increasing in what has been termed "global warming." Use this information, and your understanding of the processes of cellular respiration and photosynthesis, to answer these questions. The clear-cutting of forests may also be contributing to global warming because:

1. more carbon dioxide is released to the atmosphere.
2. there are fewer plants to remove carbon dioxide from the atmosphere.
3. more light energy is absorbed by the surface and released as heat.
4. A and B are true.
5. A, B, and C are true.

e

Which of the following is TRUE about the light-dependent reactions?

1. CO2 generates electrons for photosystem II, which are passed to photosystem I.
2. Photosystem I generates ATP, while photosystem II generates NADPH.
3. Photosystem II generates ATP, while photosystem I generates NADPH
4. NADPH and ATP are both made via an electron transport chain that connects photosystem I and photosystem II.
5. CO2 generates electrons for photosystem I, which are passed to photosystem II.

c

What structural feature of a leaf allows CO2 from the air to enter the leaf?

1. chloroplast
2. mesophyll
3. stomata
4. chlorophyll
5. bundle sheath cells

c

All of the following compounds are required (i.e., are used in chemical reactions) at some state of green plant photosynthesis, EXCEPT:

1. oxygen
2. carbon dioxide.
3. NADP.
4. water.
5. ATP.

a

CAM plants keep stomata closed in the daytime, thus reducing loss of water. They can do this because they _____.

1. fix CO2 into organic acids during the night
2. use photosystem I and photosystem II at night
3. fix CO2 into sugars in the bundle-sheath cells
4. fix CO2 into pyruvate in the mesophyll cells

a

Which of the following sequences correctly represents the flow of electrons during photosynthesis?

1. NADPH → O2 → C O2
2. NADPH → chlorophyll → Calvin cycle
3. H2O → NADPH → Calvin cycle
4. NADPH → electron transport chain → O2

c

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from _____.

1. air
2. electrons from NADPH
3. glucose
4. water

d

In C3 photosynthesis, what fixes the carbon?

1. G3P
2. ATP
3. RuBP
4. PGA
5. PEP

c

The alternative pathways of photosynthesis using the C4 or CAM systems are said to be compromises. Why?

1. CAM plants allow more water loss, while C4 plants allow less CO2 into the plant.
2. Both minimize photorespiration but expend more ATP during carbon fixation.
3. Each one minimizes both water loss and rate of photosynthesis.
4. C4 compromises on water loss and CAM compromises on photorespiration.

b

Energy is passed around different chlorophyll molecules until it reaches a specific chlorophyll molecule called the:

1. thylakoid.
2. reaction center.
3. accessory pigment.
4. photosystem.
5. electron carrier molecule.

b

If plant gene alterations cause plants to be deficient in photorespiration, what would most probably occur?

1. Photosynthetic efficiency would be reduced at low light intensities.
2. Less oxygen would be produced.
3. There would be more light-induced damage to the cells.
4. Cells would carry on the Calvin cycle at a much slower rate.

c

Compared to C3 plants, C4 plants _____.

1. do not use rubisco for carbon fixation
2. can continue to fix CO2 even at lower CO2 concentrations and higher oxygen concentrations
3. make a four-carbon compound, oxaloacetate, which is then delivered to the citric acid cycle in mitochondria
4. have higher rates of photorespiration

b

Which of the following colors of light will be most effective for growth of green plants?

1. red and green
2. orange and yellow
3. blue and green
4. red and blue
5. green and yellow

d

Plants photosynthesize _____.

1. and respire only in the light
2. only in the dark but respire only in the light
3. only in the light but respire only in the dark
4. only in the light but respire in light and dark

d

As represented by the oval at the bottom of Figure 06-01, the process depicted here produces the molecular by-product of:

1. hydrogen.
2. CO2.
3. water.
4. oxygen.
5. glucose.

d

Which component of photosynthesis is most directly linked to the production of ATP?

generation of NADPH

1. production of O2
2. photosystem II
3. splitting of a water molecule
4. photosystem I

b

During the process of photosynthesis, solar energy is primarily converted into:

1. kinetic energy.
2. nuclear energy.
3. mechanical energy.
4. chemical energy.
5. thermal energy.

d

Suppose you are studying photosynthesis in a research lab. You grow your plants in a chamber with a source of water that has a radioactively labeled oxygen atom. What photosynthetic product will be radioactive?

1. O2
2. C6H12O6
3. CO2
4. NADPH
5. ATP

a

Why are C4 plants able to photosynthesize with no apparent photorespiration?

1. They use PEP carboxylase to initially fix CO2.
2. They do not participate in the Calvin cycle.
3. They exclude oxygen from their tissues.
4. They conserve water more efficiently.

a

Which of the following is NOT true of chlorophyll?

1. It is the only light-capturing molecule involved in photosynthesis.
2. It is the main photosynthetic pigment in plants.
3. It absorbs light at the red and blue ends of the visible light spectrum.
4. It is found in thylakoids.
5. It reflects green wavelengths of light.

a

When oxygen is released as a result of photosynthesis, it is a direct by-product of _____.

1. chemiosmosis
2. splitting water molecules
3. the electron transfer system of photosystem II
4. the electron transfer system of photosystem I

b

Which of the following is a source of electrons used in photosynthesis?

1. glucose
2. RuBP
3. H2O
4. O2
5. CO2

c

Chlorophyll molecules are located in membrane-bound sacs called:

1. stroma.
2. bundle sheaths.
3. photosystems.
4. thylakoids.
5. stomata.

d

In a plant, the reactions that produce molecular oxygen (O2) take place in _____.

1. the Calvin cycle alone
2. the light reactions and the Calvin cycle
3. the light reactions alone
4. neither the light reactions nor the Calvin cycle

c

Where does the Calvin cycle take place?

1. thylakoid membrane
2. outer membrane of the chloroplast
3. interior of the thylakoid (thylakoid space)
4. stroma of the chloroplast

d

In the C4 cycle, what is the source of carbon?

1. ATP
2. NADPH
3. C6H12O6
4. CO2
5. RuBP

d

Which of the following statements best describes the relationship between photosynthesis and respiration?

1. Photosynthesis is catabolic; respiration is anabolic.
2. Photosynthesis occurs only in plants; respiration occurs only in animals.
3. Respiration runs the biochemical pathways of photosynthesis in reverse.
4. Photosynthesis stores energy in complex organic molecules; respiration releases energy from complex organic molecules

d

The electrons that leave photosystem I and travel through an electron transport system become part of:

1. H2O.
2. CO2.
3. O2.
4. NADPH.
5. glucose.

d

If pigments from a particular species of plant are extracted and subjected to paper chromatography, which of the following is most likely?

1. Paper chromatography would isolate only the pigments that reflect green light.
2. Paper chromatography would separate the pigments from a particular plant into several bands.
3. Paper chromatography for the plant would isolate a single band of pigment that is characteristic of that particular plant.
4. The isolated pigments would be some shade of green.

b

Carbon dioxide is split to form oxygen gas and carbon compounds _____.

1. in neither photosynthesis nor respiration
2. during photosynthesis
3. during respiration
4. during photosynthesis and respiration

a

What is the correct order for the reactions of the Calvin-Benson (C3) cycle?

1. production of G3P, regeneration of RuBP, carbon fixation
2. regeneration of RuBP, production of G3P, carbon fixation
3. carbon fixation, regeneration of RuBP, production of G3P
4. carbon fixation, production of G3P, regeneration of RuBP
5. production of G3P, carbon fixation, regeneration of RuBP

d

Referring to the accompanying figure, oxygen would inhibit the CO2 fixation reactions in _____.

1. neither cell I nor cell II
2. both cell I and cell II
3. cell I only
4. cell II only

d

What process does Figure 06-01 represent?

1. light-dependent reactions
2. CAM
3. C4 pathway
4. light-independent reactions
5. carbon fixation

a

What wavelength of light in the figure is most effective in driving photosynthesis?

1. 420 mm
2. 625 mm
3. 575 mm
4. 730 mm

a

Which sequence accurately reflects the flow of electrons in the light-dependent reactions of photosynthesis?

1. H2O → Photosystem I → Photosystem II → NADP
2. H2O → Photosystem II → Photosystem I → NADP
3. Photosystem II → Photosystem I → NADP → H2O
4. Photosystem I → Photosystem II → NADP → H2O
5. Photosystem I → Photosystem II → H2O → NADP

b

The primary function of the light-dependent reactions of photosynthesis is to:

1. produce phosphoglyceric acid (PGA).
2. produce energy-rich ATP and NADPH.
3. convert light energy to the chemical energy of proteins.
4. produce energy-rich glucose from carbon dioxide and water.
5. use ATP to make glucose.

b