Exam 2 Chapter 8 (Practice Questions)

Front 1

During the light reactions of photosynthesis, the synthesis of ________ is coupled to thediffusion of protons.

Back 1

ATP

Front 2

Atmospheric carbon dioxide enters plant leaves through openings called ________.

Back 2

stomata

Front 3

In the 1800s, the summarized chemical reaction for photosynthesis was incorrect becauseit left out ________as a product.

Back 3

water

Front 4

In noncyclic photophosphorylation, the electrons for the reduction of chlorophyll inphotosystem II come from ________.

Back 4

water

Front 5

When ________ are exposed to light and CO2, four-carbon compounds are the firstcarbon-containing products.

Back 5

C4 plants

Front 6

During the process of ________ rubisco catalyzes the reaction of RuBP with oxygen.

Back 6

photorespiration

Front 7

A group of scientists led by ________ conducted experiments demonstrating that RuBPis the CO2 acceptor in the dark reactions of photosynthesis.

Back 7

Calvin

Front 8

When isolated chloroplasts are shifted from a low pH solution to a more alkaline solution, ATP synthesis occurs, even in the absence of light. This experiment was used to support the ________ mechanism of ATP formation in chloroplasts.

Back 8

?

Front 9

During cyclic photophosphorylation, the energy of photons is converted to the chemicalenergy of the product, ________.

Back 9

ATP

Front 10

In C3 plants, the CalvinñBenson cycle occurs in the chloroplasts of ________ cells, but inC4 plants the cycle occurs in the ________ cells.

Back 10

mesophyll;bundle sheath

Front 11

In both photosynthesis and respiration, ________ synthesis is coupled to the diffusion ofprotons across a membrane.

Back 11

ATP

Front 12

The dark reactions take place in the ________.

Back 12

light

Front 13

NADP is the abbreviation for ________

Back 13

nicotinamideadenine dinucleotide phosphate

Front 14

The Calvin-Benson cycle is sometimes called the ________.

Back 14

darkreactions

Front 15

The oxygen found in Earth's atmosphere is generated from the photosystem ________ ofnoncyclic photophosphorylation.

Back 15

2?????

Front 16

________ instead of NADP+ receives the electron from ferredoxin during cyclicphotophosphorylation.

Back 16

plastoquinone

Front 17

The most abundant enzyme in the biosphere is ________.

Back 17

rubisco(or RuBP carboxylase)

Front 18

To obtain free energy, heterotrophs require a source of A) partially reduced organic compounds. B) light energy. C) kinetic energy. D) carbon dioxide. E) water.

Back 18

?????

Front 19

How do red and blue light differ from one another? A) They differ in intensity. B) They have a different number of photons in each quantum. C) Their wavelengths are different. D) They differ in duration. E) Red is radiant, and blue is electromagnetic.

Back 19

C

Front 20

The wavelength of X rays is shorter than the wavelength of infrared rays. Which of thefollowing is true? A) X rays have more energy per photon than infrared rays. B) X rays have a smaller value for Planck's constant than infrared waves. C) X rays have a different absorption spectrum than infrared waves. D) X rays and infrared waves have the same frequency. E) Infrared waves are in the ground state, and X rays are in the excited state.

Back 20

A

Front 21

Brightness of light is a function of A) the wavelengths of the light. B) the photons striking an area per unit time. C) wattage. D) the color of an environment. E) All of the above

Back 21

B

Front 22

A molecule has an absorption spectrum that shows maximum absorption within thewavelengths of visible light. This molecule is A) a reducing agent. B) a quantum. C) a photon. D) electromagnetic radiation. E) a pigment.

Back 22

E

Front 23

When white light strikes a blue pigment, blue light is A) reduced. B) absorbed. C) converted to chemical energy. D) reflected or transmitted. E) used to synthesize ATP.

Back 23

D

Front 24

A graph that plots the rate at which carbon dioxide is converted to glucose versus thewavelength of light illuminating a leaf is called A) a Planck equation. B) an absorption spectrum. C) enzyme kinetics. D) an electromagnetic spectrum. E) an action spectrum.

Back 24

E

Front 25

The photosynthetic pigment chlorophyll a absorbs A) infrared light. B) red and blue light. C) X rays. D) gamma rays. E) white light.

Back 25

B

Front 26

Accessory pigments A) play no role in photosynthesis. B) transfer energy from chlorophyll to the electron transport chain. C) absorb only in the red wavelengths. D) allow plants to harvest visible light of intermediate wavelengths. E) transfer electrons to NADP.

Back 26

D

Front 27

Why are the absorption spectrum of chlorophyll a and the action spectrum ofphotosynthesis not identical? A) Accessory pigments contribute energy to drive photosynthesis. B) Chlorophyll a absorbs both red and blue light. C) Chlorophyll a reflects green light. D) Different wavelengths of light have different energies. E) Chlorophyll a can be activated by absorbing a photon of light.

Back 27

A

Front 28

Excited chlorophyll is a better reducing agent than ground-state chlorophyll because A) excited chlorophyll can release energy by fluorescence. B) one of the electrons is farther from the atomic nucleus. C) excited chlorophyll is reduced by NADPH. D) excited chlorophyll absorbs light in the green wavelengths. E) only excited chlorophyll contains a porphyrin ring.

Back 28

B?????

Front 29

In cyclic photophosphorylation, chlorophyll is reduced by A) NADPH. B) a chemiosmotic mechanism. C) plastoquinone. D) ATP. E) hydrogens liberated by the splitting of a water molecule.

Back 29

C

Front 30

The energy difference between an electron excited by a photon and its ground state is A) lost. B) less than the photon. C) the same as what was in the photon. D) greater than the energy of the photon. E) greater when released by the electron.

Back 30

C

Front 31

The precise moment when light energy is captured in chemical energy is when A) light shines on chlorophyll. B) water is hydrolyzed. C) chlorophyll is oxidized. D) chlorophyll is reduced. E) the CO2 from air is captured in a sugar.

Back 31

C

Front 32

Free energy is released in cyclic photophosphorylation A) by the formation of ATP. B) during the excitation of chlorophyll. C) during the fluorescence of chlorophyll. D) during each of the redox reactions of the electron transport chain.E) when electrons are transferred from photosystem I to photosystem II.

Back 32

D

Front 33

During cyclic photophosphorylation, the energy to produce ATP is provided by A) heat. B) NADPH. C) ground state chlorophyll. D) the redox reactions of the electron transport chain. E) the CalvinñBenson cycle.

Back 33

D

Front 34

In noncyclic photophosphorylation, water is used for the A) hydrolysis of ATP. B) excitation of chlorophyll. C) reduction of chlorophyll. D) oxidation of NADPH. E) synthesis of chlorophyll.

Back 34

C

Front 35

Photophosphorylation provides the CalvinñBenson cycle with A) protons and electrons. B) CO2 and glucose. C) water and photons. D) light and chlorophyll. E) ATP and NADPH.

Back 35

E

Front 36

In noncyclic photophosphorylation, the chlorophyll in photosystem I is reduced by A) water. B) an electron from the transport chain of photosystem II. C) two photons of light. D) NADPH. E) ATP.

Back 36

B

Front 37

The enzyme ATP synthase couples the synthesis of ATP to A) the diffusion of protons. B) the reduction of NADP+. C) the excitation of chlorophyll. D) the reduction of chlorophyll. E) carbon dioxide fixation.

Back 37

A

Front 38

Use the following to answer questions 38-39:

A suspension of algae is incubated in a flask in the presence of both light and CO2. When transferred to the dark, you block the reduction of 3-phosphoglycerate to glyceraldehyde 3-phosphate.

Why does this reaction stop when the algae are placed in the dark? A) It requires carbon dioxide. B) It is an exergonic reaction. C) It requires ATP and NADPH + H+. D) It requires oxygen. E) Chlorophyll is not synthesized in the dark.

Back 38

C

Front 39

Use the following to answer questions 38-39:A suspension of algae is incubated in a flask in the presence of both light and CO2. When transferred to the dark, you block the reduction of 3-phosphoglycerate to glyceraldehyde 3-phosphate.

When the reduction of 3-phosphoglycerate to glyceraldehyde 3-phosphate is blocked, theconcentration of ribulose bisphosphate declines. Why? A) Ribulose bisphosphate is synthesized from glyceraldehyde 3-phosphate. B) Glyceraldehyde 3-phosphate is converted to glucose. C) Ribulose bisphosphate is used to synthesize 3-phosphoglycerate. D) a and c E) a and b

Back 39

E

Front 40

The enzyme rubisco is found in A) chloroplasts. B) mitochondria. C) the cytoplasm. D) the nucleus. E) yeast.

Back 40

A

Front 41

During carbon dioxide fixation, carbon dioxide combines with A) NADPH. B) 3PG. C) G3P. D) water. E) ribulose bisphosphate.

Back 41

E

Front 42

__________ mole(s) of carbon dioxide must enter the CalvinñBenson cycle for thesynthesis of one mole of glucose. A) One B) Two C) Three D) Six E) Twelve

Back 42

D

Front 43

In the experiments conducted to identify the first compound that is formed during CO2fixation, why weren't all of the compounds of the CalvinñBenson cycle labeled with 14C? A) The cells were incubated with 14CO2 for a very short time. B) The cells were incubated in the dark. C) The cells were incubated in the absence of CO2. D) The cells were incubated at very low concentrations of CO2. E) The cells were incubated in the absence of water.

Back 43

?

Front 44

The NADPH required for the reduction of 3PG to G3P comes from A) the dark reactions. B) the light reactions. C) the synthesis of ATP. D) the CalvinñBenson cycle. E) oxidative phosphorylation.

Back 44

B

Front 45

In C4 plants, the function of the four-carbon compound that is synthesized in themesophyll cells is to A) reduce NADP+. B) combine with CO2 to produce glucose. C) carry CO2 to the bundle sheath cells. D) drive the synthesis of ATP. E) close the stomata.

Back 45

C

Front 46

In the mesophyll layer of C4 plants, light energy is used to synthesize A) O2. B) G3P. C) 3PG from RuBP. D) CO2. E) oxaloacetate.

Back 46

E

Front 47

In C4 plants, starch grains are found in the chloroplasts of A) the thylakoids. B) mesophyll cells. C) the intracellular space. D) the stroma. E) bundle sheath cells.

Back 47

E

Front 48

During photorespiration, rubisco uses __________as a substrate. A) carbon dioxide B) oxygen C) glyceraldehyde 3-phosphate D) 3-phosphoglycerate E) NADPH

Back 48

B

Front 49

Photorespiration starts A) in mitochondria. B) in chloroplasts. C) only in C4 plants. D) in the microbodies. E) in the cytoplasm.

Back 49

B

Front 50

In plants, the reactions of glycolysis occur A) only in C3 plants. B) in the mitochondria. C) in the chloroplasts. D) only in the presence of light. E) in the cytosol.

Back 50

E

Front 51

In both photosynthesis and respiration, protons are pumped across a membrane during A) electron transport. B) photolysis. C) CO2 fixation. D) reduction of oxygen. E) glycolysis.

Back 51

A

Front 52

The enzyme PEP carboxylase A) can trap CO2 even at relatively low CO2 concentrations. B) catalyzes the synthesis of RuBP. C) catalyzes the synthesis of 3PG. D) is found in the chloroplasts of bundle sheath cells. E) couples the synthesis of ATP to the diffusion of protons.

Back 52

A

Front 53

The function of photorespiration is A) CO2 fixation. B) unknown. C) ATP production. D) to generate a proton gradient. E) to synthesize glucose.

Back 53

B

Front 54

The NADPH required for CO2 fixation is formed A) by the reduction of oxygen. B) by the hydrolysis of ATP. C) during the light reactions. D) only in C4 plants. E) in the mitochondria.

Back 54

C

Front 55

The O2 gas produced during photosynthesis is derived from A) carbon dioxide. B) glucose. C) water. D) carbon monoxide. E) bicarbonate ions.

Back 55

C

Front 56

Photosynthesis and respiration have which of the following in common? A) In eukaryotes, both processes reside in specialized organelles. B) ATP synthesis in both processes relies on the chemiosmotic mechanism. C) Both use electron transport. D) Both require light. E) a, b, and c

Back 56

E

Front 57

The expression "We are creatures of the chloroplasts" means that A) all life possesses chloroplasts. B) all life depends ultimately on photosynthesis. C) chloroplasts are models of all organelles. D) a and c E) None of the above

Back 57

?

Front 58

When a photon interacts with molecules such as those within chloroplasts, the photonsmay A) bounce off the molecules, having no effect. B) pass through the molecules, having no effect. C) be absorbed by the molecules. D) a and c E) a, b, and c

Back 58

E

Front 59

Which of the following scientific tools "cracked" the CalvinñBenson cycle? A) Isotopes B) Paper chromatography C) Crystallography D) Centrifugation and electron microscopy E) a and b

Back 59

E

Front 60

In noncyclic photophosphorylation, electrons from which source replenish chlorophyllmolecules that have given up electrons? A) Carbon dioxide B) Water C) NADPH + H+ D) Gaseous oxygen E) None of the above

Back 60

B

Front 61

In our past evolutionary history, noncyclic photophos- phorylation by cyanobacteria,algae, and plants poured enough gas into the atmosphere to make possible the evolution of cellular respiration. That gas was A) oxygen. B) methane. C) hydrogen. D) nitrogen. E) chlorine.

Back 61

A

Front 62

After World War II, the Berkeley group (Calvin et al.) made progress in understandingthe dark reactions when these researchers devised a way to grow dense quantities of algae in a flask that looked like a A) long test tube. B) condenser. C) pipette. D) lollipop. E) culture dish.

Back 62

?

Front 63

Which of the following biological groups is dependent on photosynthesis for its survival? A) Vertebrates B) Class Mammalia C) Fish D) a and b E) a, b, and c

Back 63

E

Front 64

Photosynthesis is divided into two main phases, the first of which is a series of reactionsthat requires the absorption of photons. This phase is referred to as the A) reduction phase. B) dark reactions phase. C) carbon fixation phase. D) light reactions phase, or photophosphorylation. E) None of the above

Back 64

D

Front 65

Based on its electronic structure, a molecule has a range of photon energies. These photon energies are known as the molecule's A) chloroplasts. B) light reactions. C) absorption spectrum. D) photosystems I and II. E) None of the above

Back 65

?

Front 66

The energy to hydrolyze water comes from A) oxidized chlorophyll. B) reduced chlorophyll. C) the proton gradient. D) ATP. E) NADPH+H+.

Back 66

A

Front 67

Heterotrophs are dependent on autotrophs for their food supply. Autotrophs can maketheir own food by A) feeding on bacteria and converting the nutrients into usable energy. B) using light and an inorganic carbon source to make reduced carbon compounds. C) synthesizing it from water and carbon dioxide. D) All of the above E) None of the above

Back 67

B

Front 68

Photosynthesis is the process that uses light energy to extract H atoms from which of thefollowing sources? A) Glucose B) Chlorophyll C) Carbon dioxide D) Water E) None of the above

Back 68

D

Front 69

Which of the following occurs during the dark reactions of photosynthesis? A) Water is converted into hydrogen and water. B) Carbon dioxide is converted into sugars. C) Chlorophyll acts as an enzyme only in the dark. D) Nothing occurs; the plant rests in the dark. E) None of the above

Back 69

B

Front 70

In bright light, the pH of the thylakoid space A) can become more acidic. B) can become more alkaline. C) stays the same; the pH of thylakoid spaces never changes. D) can become neutral. E) None of the above

Back 70

A

Front 71

When a photon is absorbed by a molecule, what exactly happens to the photon? A) It loses its ability to generate any energy. B) It raises the molecule from a ground state of low energy to an excited state. C) The exact relationship of the photon to the molecule is not clearly understood. D) It causes a change in the velocity of the wavelengths. E) None of the above

Back 71

B

Front 72

A range of energy that cannot be seen by human eyes, but has slightly more energy perphoton than visible light, is A) adaptive radiation. B) solar radiation. C) gamma radiation. D) ultraviolet radiation. E) None of the above

Back 72

D

Front 73

The main photosynthetic pigments in plants are A) chlorophyll s and chlorophyll a. B) chlorophyll x and chlorophyll y. C) retinal pigment and accessory pigment. D) chlorophyll a and chlorophyll b. E) None of the above

Back 73

D

Front 74

If one were to compare long wavelengths to short wavelengths, it would be evident thatshort-wavelength photons have A) an insignificant amount of energy. B) more energy. C) energy not available to plant cells. D) a ladder of energy. E) None of the above

Back 74

B

Front 75

The chemiosmotic hypothesis states that the energy for the production of ATP comesfrom A) the transfer of phosphate from intermediate compounds. B) the reduction of NADP. C) a proton gradient set up across the thylakoid membrane. D) the oxidation of carbon dioxide. E) None of the above

Back 75

C

Front 76

When carbon dioxide is added to RuBP, the first stable product synthesized is A) pyruvate. B) glyceraldehyde 3-phosphate. C) phosphoglycerate. D) ATP. E) None of the above

Back 76

C

Front 77

Photosynthesis takes place in plants only in the light. Respiration takes place A) in the dark only. B) in the light only. C) in all organisms except for plants. D) both with and without light. E) None of the above

Back 77

D

Front 78

The revised, balancedequation for the generation of sugar from sunlight, water, and carbon dioxideis A) 6 CO2 + 6 H2O Æ C6H12O6 + O2. B) 6 CO2 + 12 H2O Æ C6H12O6 + 6 O2 + 6 H2O. C) 6 CO2 + 6 H2O Æ C6H12O6 + 6 O2. D) 12 CO2 + 12 H2O Æ 2 C6H12O6 + 2 O2. E) None of the above

Back 78

B

Front 79

After removal of the carbon, the oxygen in the carbon dioxide ends up in A) the air. B) the sugar. C) water molecules. D) the air and sugar. E) the sugar and water molecules.

Back 79

C

Front 80

The net energy outcome of cyclic photophosphory-lation is A) ATP. B) ATP and NADH. C) ATP and NADPH. D) sugar. E) NADPH.

Back 80

A

Front 81

The air contains around ___________ carbon dioxide. A) 36% B) 3.6% C) 0.36% D) 0.036% E) 0.0036%

Back 81

D

Front 82

The concentration of oxygen in the air is A) 21%. B) 2.1%. C) 0.21%. D) 0.02%. E) It depends on where in the world you are.

Back 82

A

Front 83

In C4 plants, CO2 is first fixed into a compound called A) pyruvate. B) glucose. C) oxaloacetate. D) ribulose bisphosphate. E) 3-phosphoglycerate.

Back 83

C

Front 84

In cacti, CO2 is stored for use in the CalvinñBenson cycle A) in the stems, roots, and leaves. B) during the evening. C) in glucose molecules. D) in the stroma. E) None of the above

Back 84

B

Front 85

Plants classified as CAM store CO2 A) by making oxaloacetate. B) by making PEP carboxylase. C) in malic acid. D) in crassulacean acid. E) a and c.

Back 85

E

Front 86

The energy a plant acquires from the sun A) can all be found in the plant. B) is mostly consumed by the plant. C) is mostly consumed by heterotrophs. D) accumulates in the soil. E) All of the above are sometimes true.

Back 86

?