Chapter 07-final - practice exams PDF

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Chapter 7: Photosynthesis, Light, and Life Multiple-Choice Questions 1.

Photosynthesis: A Historical Perspective; p. 122; easy; ans: e Who provided the first experimental evidence that soil alone does not nourish the plant? a. b. c. d. e.

2.

Photosynthesis: A Historical Perspective; p. 123; moderate; ans: b The O2 evolved in photosynthesis comes from: a. b. c. d. e.

3.

6.

air “restored” by vegetation could support the breathing of animals. air is “restored” only in the presence of light and only by the green parts of the plant. photosynthesis has a light-dependent stage and a light-independent stage. isolated chloroplasts are able to produce O 2 in the absence of light. all the substance of a plant is provided by water and not the soil.

The Nature of Light; p. 125; moderate; ans: e Which of the following statements about the electromagnetic spectrum is FALSE? a. b. c. d. e.

5.

carbon dioxide. water. glucose. (CH2O). (C3H3O3).

Photosynthesis: A Historical Perspective; p. 124; easy; ans: c F. F. Blackman showed that: a. b. c. d. e.

4.

Jan Ingenhousz Aristotle F. F. Blackman Joseph Priestley Jan Baptista van Helmont

All radiations travel in waves. White light consists of a number of different colors. Different colors of light are refracted at different angles. A wavelength is the distance from one wave crest to the crest of another. The longer the wavelength of light, the more energy it has.

The Nature of Light; p. 126; easy; ans: e Light is composed of particles called: a. electrons. b. protons. c. neutrons. d. gamma rays. e. photons. The Role of Pigments; p. 126; moderate; ans: c

Chlorophyll absorbs light principally in the ______ wavelengths. a. b. c. d. e. 7.

The Role of Pigments; p. 126; difficult; ans: e An action spectrum is different from an absorption spectrum in that an action spectrum: a. b. c. d. e.

8.

provides evidence that a particular pigment is responsible for a particular process. provides information about the extent of reflectance. is the light-transmitting pattern of a pigment. is the light-absorbing pattern of a pigment. is the relative effectiveness of different wavelengths for a specific process.

The Role of Pigments; p. 126; difficult; ans: c Which of the following is the very next event that occurs when a chlorophyll molecule absorbs light? a. b. c. d. e.

9.

blue and green green and violet blue and violet violet and green green and red

The energy is released as heat. Fluorescence occurs. The electron is boosted to an excited state. Resonance energy transfer occurs. The electron is transferred to an electron transport chain.

The Role of Pigments; p. 129; easy; ans: a Which pigment occurs in all photosynthetic eukaryotes? a. b. c. d. e.

Chlorophyll a Chlorophyll b Chlorophyll c Bacteriochlorophyll Chlorobium chlorophyll

10. The Role of Pigments; p. 129; easy; ans: b The primary function of ______ is as an anti-oxidant. a. b. c. d. e.

chlorophyll a carotenoids phycobilins bacteriochlorophyll chlorobium chlorophyll

11. The Role of Pigments; p. 129; easy; ans: c

Xanthophylls and carotenes: a. b. c. d. e.

are the principal photosynthetic pigments in green plants. are the principal sources of vitamin C for humans. are carotenoids. are normally present in the cytosol rather than in plastids. can substitute for chlorophylls in photosynthesis.

12. The Reactions of Photosynthesis; p. 129; easy; ans: a The energy-transduction reactions of photosynthesis are also called the ______ reactions. a. b. c. d. e.

light dark light-independent carbon-fixation biosynthetic

13. The Reactions of Photosynthesis; p. 130; moderate; ans: e Which of the following statements about an antenna complex is FALSE? a. b. c. d. e.

It is part of a photosystem. It “funnels” energy to the reaction center. It contains chlorophyll molecules. It contains carotenoid pigments. It converts light energy into chemical energy.

14. The Reactions of Photosynthesis; pp. 130-131; difficult; ans: b The light-harvesting complex is different from a photosystem in that the light-harvesting complex: a. b. c. d. e.

lacks chlorophyll a. lacks a reaction center. lacks carotenoids. collects light energy. contains pigment-binding proteins.

15. The Reactions of Photosynthesis; p. 131; moderate; ans: c In the antenna complex, light energy is transferred from one pigment molecule to another by: a. b. c. d. e.

pigment activation. fluorescence. resonance energy transfer. reduction. oxidation.

16. The Reactions of Photosynthesis; p. 131; moderate; ans: c

In contrast to Photosystem I, Photosystem II is located primarily: a. b. c. d. e.

in the chloroplast. in the cytosol. in grana thylakoids. in stroma thylokoids in the plasma membrane.

17. The Reactions of Photosynthesis; p. 131; moderate; ans: e In Photosystem II, energized electrons are transferred from pheophytin directly to: a. b. c. d. e.

chlorophyll a. NADP+. the oxygen-evolving complex. plastoquinol. PQA.

18. The Reactions of Photosynthesis; p. 132; difficult; ans: a In the light reactions, the cytochrome b6/f complex receives electrons directly from: a. b. c. d. e.

plastoquinol. ferredoxin. pheophytin manganese. plastocyanin.

19. The Reactions of Photosynthesis; p. 132; difficult; ans: a Following photolysis, the resulting protons are released into the ______, contributing to the proton gradient across the ______ membrane. a. b. c. d. e.

lumen of the thylakoid; thylakoid chloroplast stroma; outer chloroplast chloroplast stroma; thylakoid chloroplast matrix; inner chloroplast cytosol; inner mitochondrial

20. The Reactions of Photosynthesis; pp. 132-133; moderate; ans: e The ______ complex links photosystems I and II. a. b. c. d. e.

ATP synthase light-harvesting oxygen-evolving water photolysis cytochrome b6/f

21. The Reactions of Photosynthesis; p. 133; moderate; ans: b

In photophosphorylation, the role of the ATP synthase complex is to provide a channel for protons to flow back into the: a. b. c. d. e.

lumen of the thylakoid. chloroplast stroma. intermembrane space of the mitochondrion. intermembrane space of the chloroplast. cytosol.

22. The Reactions of Photosynthesis; pp. 133-134; moderate; ans: c Which of the following events is NOT associated with Photosystem I? a. b. c. d. e.

absorption of light by antenna molecules excitation of an electron from P700 transfer of electrons from cytochromes to iron-sulfur proteins reduction of NADP+ reduction of Ao

23. The Reactions of Photosynthesis; p. 134; difficult; ans: b Which of the following statements concerning ferredoxin is FALSE? a. b. c. d. e.

It is the final electron acceptor of Photosystem I. It is found in the chloroplast grana. It transfers electrons to NADP+. It is an iron-sulfur protein. It is a mobile protein.

24. The Reactions of Photosynthesis; pp. 134-135; difficult; ans: d Which of the following is produced during noncyclic AND cyclic electron flow? a. b. c. d. e.

water NADPH sugar ATP O2

25. The Reactions of Photosynthesis; p. 135; easy; ans: c During cyclic electron flow, electrons are transferred directly from P700 to Ao to: a. b. c. d. e.

P700. P680. the photosynthetic electron transport chain. the photosynthetic ATP synthase. the lumen of the thylakoid.

26. The Carbon-Fixation Reactions; p. 135; moderate; ans: b

The Calvin cycle takes place in the: a. b. c. d. e.

lumen of the thylakoid. chloroplast stroma. thylakoid membrane. cytoplasm. mitochondrial matrix.

27. The Carbon-Fixation Reactions; p. 136; easy; ans: c Carbon dioxide is “fixed” by bonding to: a. b. c. d. e.

glyceraldehyde 3-phosphate. 3-phosphoglycerate. ribulose 1,5-bisphosphate. NADP+. ADP.

28. The Carbon-Fixation Reactions; p. 136; easy; ans: a The role of Rubisco is to catalyze the conversion of: a. b. c. d. e.

CO2 to an unstable six-carbon compound. CO2 to glyceraldehyde 3-phosphate. 3-phosphoglycerate to glyceraldehyde 3-phosphate. glyceraldehyde 3-phosphate to sucrose. glyceraldehyde 3-phosphate to starch.

29. The Carbon-Fixation Reactions; p. 136; easy; ans: a How many molecules of CO2 are fixed during each turn of the Calvin cycle? a. b. c. d. e.

one two three four five

30. The Carbon-Fixation Reactions; p. 136; difficult; ans: b Which of the following does NOT occur in the Calvin cycle? a. b. c. d. e.

ATP is hydrolyzed. ADP is phosphorylated to ATP. NADPH is oxidized. Ribulose 1,5-bisphosphate is regenerated. CO2 is fixed.

31. The Carbon-Fixation Reactions; p. 136; difficult; ans: e

Which of the following statements about the Calvin cycle is FALSE? a. b. c. d. e.

It requires more ATP than NADPH. Each reaction is catalyzed by a specific enzyme. It regenerates ribulose 1,5-bisphosphate. It fixes CO2. It uses ATP from noncyclic, but not cyclic, photophosphorylation.

32. The Carbon-Fixation Reactions; p. 138; easy; ans: d Most of the glyceraldehyde 3-phosphate not exported to the cytosol is converted to ______ and stored in the chloroplasts. a. b. c. d. e.

3-phosphoglycerate sucrose glucose starch ribulose 1,5-bisphosphate

33. The Carbon-Fixation Reactions; p. 138; easy; ans: b Rubisco can use ______ or CO2 as a substrate. a. b. c. d. e.

3-phosphoglycerate O2 glyceraldehyde 3-phosphate serine oxaloacetate

34. The Carbon-Fixation Reactions; p. 138; moderate; ans: a Which of the following statements about photorespiration is FALSE? a. b. c. d. e.

It yields ATP but not NADPH. Phosphoglycolate is an intermediate. It consumes oxygen and releases CO2. It is a wasteful process. Three cellular organelles participate in the process.

35. The Carbon-Fixation Reactions; p. 139; difficult; ans: d Which of the following conditions favors photorespiration? a. b. c. d. e.

a ratio of CO2 to O2 that favors CO2 conditions that cause the stomata to open plants growing far apart a hot, dry environment darkness

36. The Carbon-Fixation Reactions; p. 140; moderate; ans: b

One of the benefits of photorespiration is removing toxic: a. b. c. d. e.

3-phosphoglyceraldehyde. phosphoglycolate. ribulose-bisphosphate. 3-phosphoglycerate. oxaloacetate.

37. The Carbon-Fixation Reactions; p. 140; moderate; ans: e In the C4 pathway, the enzyme PEP carboxylase: a. b. c. d. e.

uses O2 as a substrate. uses CO2 as a substrate. operates inefficiently when the CO2 concentration is low. is active only in the chloroplasts of mesophyll cells. catalyzes the formation of oxaloacetate.

38. The Carbon-Fixation Reactions; p. 142; moderate; ans: a The malate or aspartate produced in the C4 pathway moves next into: a. b. c. d. e.

the bundle-sheath cells. the mesophyll cells. the stomata. Photosystem I. Photosystem II.

39. The Carbon-Fixation Reactions; p. 143; easy; ans: b Kranz anatomy is characterized by a layer of ____ around a layer of ____. a. b. c. d. e.

xylem cells; mesophyll cells mesophyll cells; bundle-sheath cells mesophyll cells; phloem cells bundle-sheath cells; phloem cells bundle-sheath cells; mesophyll cells

40. The Carbon-Fixation Reactions; p. 143; moderate; ans: c Suaeda aralocaspica is different from many other C4 plants because it: a. b. c. d. e.

has only one type of chloroplast. has Kranz anatomy. lacks Kranz anatomy. has bundle-sheath cells. lacks bundle-sheath cells.

41. The Carbon-Fixation Reactions; p. 143; difficult; ans: e

Compared with a C3 plant, a C4 plant: a. b. c. d. e.

carries out more photorespiration. has a lower photosynthetic efficiency. has more Rubisco. has a higher leaf nitrogen content. needs more ATP to fix CO2.

42. The Carbon-Fixation Reactions; p. 144; easy; ans: d Which of the following is a C4 plant? a. b. c. d. e.

rice oats Kentucky bluegrass crabgrass wheat

43. The Carbon-Fixation Reactions; p. 144; moderate; ans: d Compared with C3 plants, C4 plants: a. b. c. d. e.

are well adapted to low light intensities. are well adapted to low temperatures. are well adapted to moist areas. use nitrogen more efficiently. fix CO2 less efficiently.

44. The Carbon-Fixation Reactions; p. 145; easy; ans: a In CAM plants, malate formed as the end product of CO 2 fixation in the dark is stored as malic acid in the: a. b. c. d. e.

vacuole. chloroplast stroma. thylakoid lumen. cytosol. nucleus.

45. The Carbon-Fixation Reactions; p. 145; moderate; ans: c Which of the following is most likely to occur in a leaf cell of a CAM plant during the day? a. b. c. d. e.

entry of CO2 through stomata exit of water through stomata decarboxylation of malic acid fixation of CO2 by PEP carboxylase conversion of oxaloacetate to malate

46. The Carbon-Fixation Reactions; p. 145; easy; ans: e

Which of the following is not considered a CAM plant? a. b. c. d. e.

cactus pineapple Spanish “moss” Welwitschia wheat

47. The Carbon-Fixation Reactions; p. 146; difficult; ans: b Which of the following statements about CAM plants is FALSE? a. b. c. d. e.

Not all CAM plants are succulent. All CAM plants are flowering plants. They use both C3 and C4 pathways. They are dependent on nighttime accumulation of CO 2 for photosynthesis. Their water-use efficiency is higher than that of C3 and C4 plants.

True-False Questions 1.

Photosynthesis: A Historical Perspective; p. 124; moderate; ans: T C. B. van Neil’s experiments provided evidence that water, not carbon dioxide, was the source of the oxygen in photosynthesis.

2.

The Nature of Light; p. 125; easy; ans: F The energy of a photon of light is directly proportional to its wavelength.

3.

The Role of Pigment; p. 126; easy; ans: F Chlorophyll absorbs light principally in the green wavelength.

4.

The Role of Pigments; p. 126; moderate: ans: T An action spectrum can be used to demonstrate the relative effectiveness of different wavelengths of light for photosynthesis.

5.

The Role of Pigments; p. 129; moderate; ans: F Accessory pigments are directly involved in the energy-transduction processes of photosynthesis.

6.

The Role of Pigments; p. 129; easy; ans: F All photosynthetic eukaryotes contain both chlorophylls a and b.

7.

The Role of Pigments; p. 129; easy; ans: T Phycobilins are water-soluble accessory pigments found in cyanobacteria and red algae.

8.

The Reactions of Photosynthesis; pp. 130-131; moderate; ans: T The light-harvesting complex contains does not contain a reaction center.

9.

The Reactions of Photosynthesis; p. 131; easy; ans: F At the reaction center of Photosystem II is P700.

10. The Reactions of Photosynthesis; p. 131; moderate; ans: T

In Photosystem II, pheophytin passes an electron directly to plastoquinone. 11. The Reactions of Photosynthesis; pp. 131-132; easy; ans: T The photolysis of water occurs in conjunction with Photosystem II but not Photosystem I. 12. The Reactions of Photosynthesis; pp. 132-133; easy; ans: T The cytochrome b6/f complex links Photosystems II and I. 13. The Reactions of Photosynthesis; p. 133; moderate; ans: F Protons flow through the ATP synthesis from the stroma into the thylakoid lumen. 14. The Reactions of Photosynthesis; p. 135; easy; ans: F In the process of cyclic photophosphorylation, both ATP and NADPH are produced. 15. The Carbon-Fixation Reactions; p. 135; moderate; ans: T The ATP and NADPH generated by the light reactions are used in the Calvin cycle. 16. The Carbon-Fixation Reactions; p. 138; easy; ans: T Rubisco can use either O2 or CO2 as a substrate. 17. The Carbon-Fixation Reactions; p. 138; easy; ans: F Photorespiration is an energetically wasteful process that seldom occurs in nature. 18. The Carbon-Fixation Reactions; p. 138; easy; ans: F The concentration of CO2 in the Earth’s atmosphere is approximately 3 percent. 19. The Carbon-Fixation Reactions; p. 140; moderate; ans: T One of the benefits of photorespiration is to remove phosphoglycolate from the plant. 20. The Carbon-Fixation Reactions; p. 142; easy; ans: T The leaf anatomy of C4 plants provides a spatial separation between the C4 pathway and the Calvin cycle. 21. The Carbon-Fixation Reactions; p. 145; moderate; ans: F C3-C4 intermediates provide evidence for the evolution of C3 plants from C4 ancestors. 22. The Carbon-Fixation Reactions; p. 145; easy; ans: T Some CAM plants can keep their stomata closed night and day. 23. The Carbon-Fixation Reactions; p. 147; moderate; ans: T Under extremely dry conditions, CAM plants outcompete C3 and C4 plants.

Essay Questions

1.

Photosynthesis: A Historical Perspective; pp. 122–124; moderate Summarize the key historical events in the elucidation of the photosynthetic process.

2.

The Role of Pigments; pp. 126–127; moderate Discuss the three possible fates of an electron of a chlorophyll molecule once that electron has been raised to an excited state.

3.

The Role of Pigments; pp. 127–129; moderate List the main accessory pigments found in photosynthetic organisms. What roles do they play?

4.

The Reactions of Photosynthesis; p. 130 (Fig. 7-9); difficult Make a drawing of a chloroplast, and label the following components: inner chloroplast membrane, grana, stroma, thylakoids, and thylakoid lumen. Then, indicate the location where the Calvin cycle occurs. Finally, use arrows to show how the following molecules are involved in photosynthesis: CO2, O2, H2O, ATP, ADP, NAD+, and NADPH.

5.

The Reactions of Photosynthesis; pp. 130–132; moderate How is Photosystem I different from Photosystem II? How is it similar?

6.

The Reactions of Photosynthesis, pp. 134–135; moderate Explain the similarities and differences between (a) cyclic and noncyclic electron flow and (b) cyclic and noncyclic photophosphorylation.

7.

The Carbon-Fixation Reactions; p. 136; moderate Summarize the three main stages of the Calvin cycle.

8.

The Carbon-Fixation Reactions; pp. 138–139; moderate Describe the main events occurring in photorespiration. Under what conditions is photorespiration enhanced?

9.

The Carbon-Fixation Reactions; pp. 143-144; difficult What factors enable C4 plants to maintain a high CO2:O2 ratio at the site of Rubisco action?

10. The Carbon-Fixation Reactions; pp. 143–144; moderate Even though C4 photosynthesis requires more ATP than C3 photosynthesis, the C4 pathway is more efficient. Explain this apparent contradiction. 11. The Carbon-Fixation Reactions; pp. 144–145; difficult Design an experiment to show how Kentucky bluegrass could overwhelm crabgrass under certain environmental conditions, but just the opposite would occur under other conditions. 12. The Carbon-Fixation Reactions; pp. 135–147; difficult Compare and contrast C3, C4, and CAM photosynthesis....