1) The process of photosynthesis probably originated _____.

A) in plants
B) in prokaryotes
C) in fungi

D) three separate times during evolution

Answer: B

2) In autotrophic bacteria, where is chlorophyll located?

A) in chloroplast membranes
B) in the ribosomes
C) in the nucleoid

D) in the infolded plasma membrane

Answer: D

3) Plants photosynthesize _____.
A) only in the light but respire only in the dark

B) only in the dark but respire only in the light

C) only in the light but respire in light and dark

D) and respire only in the light

Answer: C

4) Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from _____.
A) water
B) glucose

C) air
D) electrons from NADPH

Answer: A

5) 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 _____.
A) glyceraldehyde 3-phosphate (G3P)
B) glucose

C) ribulose bisphosphate (RuBP)

D) O2

Answer: D

6) Every ecosystem must have _____.

A) autotrophs and heterotrophs
B) producers and primary consumers

C) photosynthesizers

D) autotrophs

Answer: D

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

A) splitting water molecules
B) chemiosmosis
C) the electron transfer system of photosystem I

D) the electron transfer system of photosystem II

Answer: A

8) Which of the following statements is a correct distinction between autotrophs and heterotrophs?
A) Cellular respiration is unique to heterotrophs.
B) Only heterotrophs have mitochondria.

C) Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other

nutrients that are inorganic.
D) Only heterotrophs require oxygen.

Answer: C

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.

11) What did Engelmann conclude about the congregation of bacteria in the red and blue areas?

A) Bacteria congregated in these areas due to an increase in the temperature of the red and blue light.
B) Bacteria congregated in these areas because these areas had the most oxygen being released.

C) Bacteria are attracted to red and blue light and thus these wavelengths are more reactive than other wavelengths.

D) Bacteria congregated in these areas due to an increase in the temperature caused by an increase in photosynthesis.

Answer: B

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.

12) An outcome of Engelmann's experiment was to help determine the relationship between _____.
A) wavelengths of light and the rate of aerobic respiration
B) wavelengths of light and the amount of heat released

C) wavelengths of light and the rate of photosynthesis
D) the concentration of carbon dioxide and the rate of photosynthesis

Answer: C

A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. Since the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed.

13) What wavelengths of light should be used to maximize plant growth with a minimum of energy expenditure?
A) full-spectrum white light
B) green light

C) a mixture of blue and red light
D) UV light

Answer: C

A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. Since the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed.

14) Suppose a plant has a unique photosynthetic pigment and the leaves of this plant appear to be reddish yellow. What wavelengths of visible light are absorbed by this pigment?
A) red and yellow
B) blue and violet

C) green and yellow
D) blue, green, and red

Answer: B

15) 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?

A) red and yellow
B) blue, green, and red
C) green and yellow
D) blue and red

Answer: C

16) Why are there several structurally different pigments in the reaction centers of photosystems?
A) Excited electrons must pass through several pigments before they can be transferred to electron acceptors of the electron transport chain.
B) This arrangement enables the plant to absorb light energy of a variety of wavelengths.
C) They enable the plant to absorb more photons from light energy, all of which are at the same wavelength.
D) They enable the reaction center to excite electrons to a higher energy level.

Answer: B

17) If pigments from a particular species of plant are extracted and subjected to paper chromatography, which of the following is most likely?
A) Paper chromatography for the plant would isolate a single band of pigment that is characteristic of that particular plant.

B) Paper chromatography would separate the pigments from a particular plant into several bands.

C) The isolated pigments would be some shade of green.
D) Paper chromatography would isolate only the pigments that reflect green light.

Answer: B

18) In autumn, the leaves of deciduous trees change colors. This is because chlorophyll is degraded and _____.
A) carotenoids and other pigments are still present in the leaves
B) the degraded chlorophyll changes into many other colors

C) water supply to the leaves has been reduced
D) sugars are sent to most of the cells of the leaves

Answer: A

19) What event accompanies energy absorption by chlorophyll (or other pigment molecules of the antenna complex)?
A) ATP is synthesized from the energy absorbed.
B) A carboxylation reaction of the Calvin cycle occurs.

C) Electrons are stripped from NADPH.
D) An electron is excited.

Answer: D

20) As electrons are passed through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy?
A) It excites electrons of the reaction center of photosystem I.
B) It is lost as heat.

C) It is used to establish and maintain a proton gradient.

D) It is used to phosphorylate NAD+ to NADPH, the molecule that accepts electrons from photosystem I.

Answer: C

21) The final electron acceptor associated with photosystem I is _____.

A) oxygen
B) water
C) NADP

D) NADPH

Answer: C

22) The electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?
A) the electron carrier, plastocyanin
B) photosystem I

C) water
D) oxygen

Answer: C

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

A) split water and release oxygen from the reaction-center chlorophyll
B) absorb and transfer light energy to the reaction-center chlorophyll
C) synthesize ATP from ADP and

Pi
D) transfer electrons to ferredoxin and then NADPH

Answer: B

24) Which of the following are directly associated with photosystem I?
A) receiving electrons from the thylakoid membrane electron transport chain

B) generation of molecular oxygen
C) extraction of hydrogen electrons from the splitting of water
D) passing electrons to the cytochrome complex

Answer: A

25) Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be to _____.

A) determine if they have thylakoids in the chloroplasts
B) test for liberation of O2 in the light

C) test for CO2 fixation in the dark
D) do experiments to generate an action spectrum

Answer: B

26) What are the products of linear electron flow?

A) heat and fluorescence
B) ATP and P700
C) ATP and NADPH

D) ADP and NADP+

Answer: C

27) As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find that 30,000 molecules of ATP were consumed, but only 20,000 molecules of NADPH were consumed. Where did the extra ATP molecules come from?
A) photosystem II
B) photosystem I
C) cyclic electron flow
D) linear electron flow

Answer: C

28) Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will most directly affect the _____.
A) splitting of water
B) flow of electrons from photosystem II to photosystem I

C) synthesis of ATP

D) reduction of NADP+

Answer: C

29) In a plant cell, where are the ATP synthase complexes located? A) thylakoid membrane only
B) inner mitochondrial membrane only
C) thylakoid membrane and inner mitochondrial membrane

D) thylakoid membrane and plasma membrane

Answer: C

30) In mitochondria, chemiosmosis moves protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis moves protons from the _____.
A) matrix to the stroma
B) stroma to the thylakoid space

C) intermembrane space to the matrix
D) thylakoid space to the stroma

Answer: B

31) Which of the following statements best describes the relationship between photosynthesis and respiration?
A) Respiration runs the biochemical pathways of photosynthesis in reverse.
B) Photosynthesis stores energy in complex organic molecules; respiration releases energy from complex organic molecules

C) Photosynthesis occurs only in plants; respiration occurs only in animals.

D) Photosynthesis is catabolic; respiration is anabolic.

Answer: B

32) In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during _____.
A) photosynthesis only
B) respiration only

C) photosynthesis and respiration
D) neither photosynthesis nor respiration

Answer: C

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

A) during photosynthesis
B) during respiration
C) during photosynthesis and respiration

D) in neither photosynthesis nor respiration

Answer: D

34) What is the relationship between the wavelength of light and the quantity of energy per photon?
A) They have a direct, linear relationship.
B) They are inversely related.

C) They are logarithmically related.
D) They are separate phenomena.

Answer: B

35) P680+ is said to be the strongest biological oxidizing agent. Given its function, why is this necessary?
A) It is the receptor for the most excited electron in either photosystem of photosynthesis.
B) It is the molecule that transfers electrons to plastoquinone (Pq) of the electron transfer system.

C) It transfers its electrons to reduce NADP+ to NADPH.
D) It obtains electrons from the oxygen atom in a water molecule, so it must have a stronger attraction for electrons than oxygen has.

Answer: D

36) Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. What related function do they have in plants?
A) They serve as accessory pigments to increase light absorption.
B) They protect against oxidative damage from excessive light energy.

C) They shield the sensitive chromosomes of the plant from harmful ultraviolet radiation.

D) They reflect orange light and enhance red light absorption by chlorophyll.

Answer: B

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

A) the light reactions alone
B) the Calvin cycle alone
C) the light reactions and the Calvin cycle
D) neither the light reactions nor the Calvin cycle

Answer: A

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

A) life and respiratory metabolism
B) cyanobacteria using photosystem II
C) chloroplasts in photosynthetic eukaryotic algae

D) land plants

Answer: B

39) In its mechanism, photophosphorylation is most similar to _____.

A) substrate-level phosphorylation in glycolysis
B) oxidative phosphorylation in cellular respiration
C) the Calvin cycle

D) reduction of NADP+

Answer: B

40) Which process is most directly driven by light energy?
A) creation of a pH gradient by pumping protons across the thylakoid membrane

B) carbon fixation in the stroma

C) reduction of NADP+ molecules
D) removal of electrons from chlorophyll molecules

Answer: D

41) A gardener is concerned that her greenhouse is getting too hot from too much light and seeks to shade her plants with colored translucent plastic sheets, the color of which allows passage of only that wavelength. What color should she use to reduce overall light energy but still maximize plant growth?

A) green
B) blue
C) orange
D) Any color will work equally well.

Answer: B

42) 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 _____.

A) always be higher
B) always be lower
C) be higher in the light, but the same in the dark

D) be higher in the light, but lower in the dark

Answer: D

43) Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
A) CO2 and glucose

B) H2O and O2

C) ADP, Pi, and NADP+

D) ATP and NADPH

Answer: D

44) Where does the Calvin cycle take place?

A) stroma of the chloroplast
B) thylakoid membrane
C) interior of the thylakoid (thylakoid space) D) outer membrane of the chloroplast

Answer: A

45) What is the primary function of the Calvin cycle?

A) use NADPH to release carbon dioxide
B) split water and release oxygen
C) transport RuBP out of the chloroplast

D) synthesize simple sugars from carbon dioxide

Answer: D

46) In the process of carbon fixation, RuBP attaches a CO2 to produce a six-carbon molecule,

which is then split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle?
A) addition of a pair of electrons from NADPH

B) regeneration of ATP from ADP

C) regeneration of RuBP

D) regeneration of NADP+

Answer: C

49) Which of the following sequences correctly represents the flow of electrons during photosynthesis?
A) NADPH → O2 → C O2
B) H2O → NADPH → Calvin cycle

C) NADPH → chlorophyll → Calvin cycle
D) NADPH → electron transport chain → O2

Answer: B

50) Which of the following does NOT occur during the Calvin cycle?

A) oxidation of NADPH
B) release of oxygen
C) regeneration of the CO2 acceptor

D) consumption of ATP

Answer: B

51) What compound provides the reducing power for Calvin cycle reactions?

A) ATP
B) NADH

C) NADP+
D) NADPH

Answer: D

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

A) All plants would experience increased rates of photosynthesis.
B) C3 plants would have faster growth; C4 plants would be minimally affected.

C) C4 plants would have faster growth; C3 plants would be minimally affected.

D) C3 plants would have faster growth; C4 plants would have slower growth.

Answer: B

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

A) They do not participate in the Calvin cycle.
B) They use PEP carboxylase to initially fix CO2.

C) They conserve water more efficiently.
D) They exclude oxygen from their tissues.

Answer: B

54) CAM plants keep stomata closed in the daytime, thus reducing loss of water. They can do this because they _____.
A) fix CO2 into organic acids during the night
B) fix CO2 into sugars in the bundle-sheath cells

C) fix CO2 into pyruvate in the mesophyll cells

D) use photosystem I and photosystem II at night

Answer: A

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

A) Each one minimizes both water loss and rate of photosynthesis.
B) C4 compromises on water loss and CAM compromises on photorespiration.

C) Both minimize photorespiration but expend more ATP during carbon fixation.
D) CAM plants allow more water loss, while C4 plants allow less CO2 into the plant.

Answer: C

56) If plant gene alterations cause plants to be deficient in photorespiration, what would most probably occur?
A) Photosynthetic efficiency would be reduced at low light intensities.
B) Cells would carry on the Calvin cycle at a much slower rate.

C) There would be more light-induced damage to the cells.

D) Less oxygen would be produced.

Answer: C

57) Compared to C3 plants, C4 plants _____.
A) can continue to fix CO2 even at lower CO2 concentrations and higher oxygen concentrations

B) have higher rates of photorespiration
C) do not use rubisco for carbon fixation
D) make a four-carbon compound, oxaloacetate, which is then delivered to the citric acid cycle in mitochondria

Answer: A

60) Photorespiration _____.
A) generates carbon dioxide and consumes ATP and oxygen
B) generates ATP and sugars and consumes oxygen and carbon dioxide

C) generates oxygen and consumes ATP, carbon dioxide, and sugars

D) consumes carbon dioxide and generates ATP, sugars, and oxygen

Answer: A