Chapter 10 MB

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. orange c. blue d. Any color will work equally well.

c

C4 plants differ from C3 and CAM plants in that C4 plants _____. a. are better adapted to wet conditions b. open their stomata only at night c. transfer fixed carbon dioxide to cells in which the Calvin cycle occurs d. use PEP carboxylase to fix carbon dioxide e. use malic acid to transfer carbon dioxide to the Calvin cycle

c

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. ribulose bisphosphate (RuBP) c. O2 d. glucose

c

Plants photosynthesize _____. a. and respire only in the light b. only in the light but respire only in the dark c. only in the light but respire in light and dark d. only in the dark but respire only in the light

c

Select the most accurate statement describing the basic function of the light reactions of photosynthesis. a. The basic function of the light reactions of photosynthesis is the production of glucose. b. The basic function of the light reactions of photosynthesis is the trapping of light energy. c. The basic function of the light reactions of photosynthesis is the conversion of solar energy to chemical energy.

c

How is photosynthesis similar in C4 plants and CAM plants? a. In both cases, thylakoids are not involved in photosynthesis. b. Both types of plants make sugar without the Calvin cycle. c. Both types of plants make most of their sugar in the dark. d. In both cases, rubisco is not used to fix carbon initially. e. In both cases, only photosystem I is used.

d

In C3 plants the conservation of water promotes _____. a. a shift to C4 photosynthesis b. the light reactions c. the opening of stomata d. photorespiration e. photosynthesis

d

In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells. a. stomata b. stroma c. grana d. cytoplasm e. thylakoids

d

In autumn, the leaves of deciduous trees change colors. This is because chlorophyll is degraded and _____. a. water supply to the leaves has been reduced b. the degraded chlorophyll changes into many other colors c. sugars are sent to most of the cells of the leaves d. carotenoids and other pigments are still present in the leaves

d

In mitochondria, chemiosmosis moves protons from the intermembrane space into the matrix, 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

d

Plants are photoautotrophs. What does this mean? a. They are the primary consumers of the biosphere. b. They synthesize their own food from inorganic materials. c. They generate oxygen. d. They are attracted to light. e. They use light energy to drive the synthesis of organic molecules from inorganic materials.

d

Referring to the accompanying figure, oxygen would inhibit the CO2 fixation reactions in _____. a. neither cell I nor cell II b. both cell I and cell II c. cell I only d. cell II only

d

The process of photosynthesis probably originated _____. a. in plants b. in fungi c. three separate times during evolution d. in prokaryotes

d

The ultimate source of energy to support most life on Earth is _____. a. chemosynthetic microbes b. the carbon cycle c. photosynthetic plants d. sunlight e. geothermal heat

d

What is the biological significance of the light-independent reactions of photosynthesis? a. They convert ATP to sugar. b. They make oxygen. c. They generate ATP and NADPH. d. They convert carbon dioxide to sugar.

d

What is the importance of the light-independent reactions in terms of carbon flow in the biosphere? a. The light-independent reactions use CO2 to make ATP. b. The light-independent reactions turn glucose, a sugar, into CO2 gas. c. The light-independent reactions turn sugar into ATP for energy. d. The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.

d

Which of the following reactions ensures that the Calvin cycle can make a continuous supply of glucose? a Carbon fixation b. Production of G3P c. Production of 3-phosphoglycerate d. Regneration of RuBP

d

In mechanism, photophosphorylation is most similar to a. substrate-level phosphorylation in glycolysis. b. carbon fixation. c. the Calvin cycle. d. reduction of NADP+. e. oxidative phosphorylation in cellular respiration.

e

Which of the following does not occur during the Calvin cycle? a. regeneration of the CO2 acceptor b. consumption of ATP c. carbon fixation d. oxidation of NADPH e. release of oxygen

e

Which of the following is a product of the light reactions of photosynthesis? a. NADP+ and RuBP b. glyceraldehyde-3-phosphate c. high-energy photons d. water and CO2 e. oxygen, ATP, and NADPH

e

he overall function of the Calvin cycle is _____. a. splitting water b. oxidizing glucose c. producing carbon dioxide d. capturing sunlight e. making sugar

e

CAM plants keep stomata closed in the daytime, thus reducing loss of water. They can do this because they _____. a. fix CO2 into pyruvate in the mesophyll cells b. fix CO2 into organic acids during the night c. use photosystem I and photosystem II at night d, fix CO2 into sugars in the bundle-sheath cells

b

Every ecosystem must have _____. a. producers and primary consumers b. autotrophs c. autotrophs and heterotrophs d. photosynthesizers

b

In a plant, the reactions that produce molecular oxygen (O2) take place in _____. a. the Calvin cycle alone b. the light reactions alone c. the light reactions and the Calvin cycle d. neither the light reactions nor the Calvin cycle

b

Select the correct statement about the Calvin cycle. a. The Calvin cycle takes place primarily in the dark. b. The Calvin cycle has three phases: carbon fixation, reduction, and regeneration of RuBP. c. The basic function of the Calvin cycle is the conversion of solar energy to chemical energy.

b

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. water c. oxygen d. photosystem I

b

The light reactions of photosynthesis supply the Calvin cycle with a. CO2 and ATP. b. ATP and NADPH. c. H2O and NADPH. d. light energy. e. sugar and O2.

b

What compound provides the reducing power for Calvin cycle reactions? a. NADH b. NADPH c. ATP d. NADP+

b

Which process is most directly driven by light energy? a. carbon fixation in the stroma b. removal of electrons from chlorophyll molecules c. creation of a pH gradient by pumping protons across the thylakoid membrane d. reduction of NADP+ molecules e. ATP synthesis

b

Which process produces oxygen? a. Cellular respiration b. Photosynthesis

b

Why are C4 plants able to photosynthesize with no apparent photorespiration? a. They conserve water more efficiently. b. They use PEP carboxylase to initially fix CO2. c. They do not participate in the Calvin cycle. d. They exclude oxygen from their tissues.

b

n autotrophic bacteria, where is chlorophyll located? a. in the infolded plasma membrane b. in the nucleoid c. in chloroplast membranes d. in the ribosomes

a

Which wavelengths of light drive the highest rates of photosynthesis? Select the two best answers. a. 400-450 nm b. 500-600 nm c. 550-700 nm d. 670-680 nm

a & d

Carbon dioxide is split to form oxygen gas and carbon compounds _____. a. in neither photosynthesis nor respiration b. during respiration c. during photosynthesis and respiration d. during photosynthesis

a

In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____. a. ultraviolet radiation and infrared radiation b. X-rays and ultraviolet radiation c. radio waves and microwaves d. infrared radiation and radio waves e. infrared radiation and microwaves

a

Photosynthesis is a redox reaction. This means that H2O is _____ during the light reactions and CO2 is _____ during the Calvin cycle. a. oxidized...reduced b. reduced...oxidized c. consumed...consumed d. consumed...reduced e. reduced...reduced

a

Refer to the figure. To identify the molecule that accepts CO2, Calvin and Benson manipulated the carbon-fixation cycle by either cutting off CO2 or cutting off light from cultures of photosynthetic algae. They then measured the concentrations of various metabolites immediately following the manipulation. How would these experiments help identify the CO2 acceptor? a. The CO2 acceptor concentration would increase when the CO2 is cut off, but decrease when the light is cut off. b. The CO2 acceptor concentration would decrease when the CO2 is cut off, but increase when the light is cut off. c. The CO2 acceptor concentration would decrease when either the CO2 or light are cut off. d, The CO2 acceptor concentration would increase when either the CO2 or light are cut off.

a

Select the correct molecule that is the main product of the Calvin cycle. a. G3P b. Glucose c. NADPH

a

True or false? The light-dependent reactions of photosynthesis use water and produce oxygen. a. True b. False

a

What are the products of linear electron flow? a. ATP and NADPH b. heat and fluorescence c. ATP and P700 d. ADP and NADP+

a

What is the basic role of CO2 in photosynthesis? a. CO2 is fixed or incorporated into organic molecules. b. CO2 is taken in by plants as a form of inverse respiration, in which carbon dioxide is "breathed in" and oxygen is "breathed out." c. CO2 is a source of electrons in the formation of organic molecules.

a

What is the primary function of the Calvin cycle? a. synthesize simple sugars from carbon dioxide b. transport RuBP out of the chloroplast c. use NADPH to release carbon dioxide d. split water and release oxygen

a

Which of the following statements is a correct distinction between autotrophs and heterotrophs? a. Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic. b. Only heterotrophs have mitochondria. c. Cellular respiration is unique to heterotrophs. d. Only heterotrophs require oxygen. e. Only heterotrophs require chemical compounds from the environment.

a

Which set of reactions uses H2O and produces O2? a. The light-dependent reactions b. The light-independent reactions

a

Students conducted an experiment to determine the effect of light intensity on the rate of photosynthesis. They punched 40 leaf disks from spinach leaves and used a syringe partially filled with water to pull the gases from the leaf disks so that all leaf disks sunk to the bottom of the syringe. Ten (10) leaf disks from the syringe were placed in each of four cups and covered with 50 ml of the solutions as indicated below. All leaf disks were resting on the bottom of the cups when the experiment began. The volume of liquid in each cup and the temperature of the solutions were held constant. All cups were placed 0.5 meters from the designated light source. A large beaker of water was placed between the light and the cups to act as a heat sink to prevent a change in temperature. At the end of 10 minutes, the number of disks floating in each cup was recorded. Trial Grams of baking soda (CO22 source) Wattage of light bulb Disks floating at 10 minutes 1 0.5 25 3 2 0.5 50 5 3 0.5 75 9 4 0 75 0 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. a. 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. b. Cup 3 had the same rate of photosynthesis as Cup 1 because they had the same ratio of disks floating to wattage of light. c. Cup 4 had the slowest rate of photosynthesis because it had the least baking soda. d. Cup 1 had a low rate of photosynthesis because 0.5 grams of baking soda did not provide a sufficient amount of CO2.

c

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. green and yellow b. blue, green, and red c. blue and violet d. red and yellow

c

The photosynthetic membranes are found in the _____ in plant cells. a. endoplasmic reticulum b. nucleus c. chloroplasts d. mitochondria e. Golgi apparatus

c

When light strikes chlorophyll molecules, they lose electrons, which are ultimately replaced by _____. a. removing them from NADPH b. oxidizing glucose c. splitting water d. breaking down ATP e. fixing carbon

c

Which of the following molecules is the primary product of photosystem I? a. Oxygen b. Carbon dioxide c. NADPH d. ATP

c

Which of the following products of the light reactions of photosynthesis is consumed during the Calvin cycle? a. sugar b. oxygen c. NADPH d. water e. ADP + Pi

c

Which of the following sequences correctly represents the flow of electrons during photosynthesis? a. NADPH → O2 → CO2 b. H2O → photosystem I → photosystem II c. H2O → NADPH → Calvin cycle d. NADPH → electron transport chain → O2 e. NADPH → chlorophyll → Calvin cycle

c

Why are plants classified as producers? a. Plants are classified as producers because they produce oxygen. b. Plants are classified as producers because they are at the bottom of the food chain. c. Plants are classified as producers because they fix inorganic carbon into organic molecules.

c

Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis? a. The light-independent reactions release energy, and the light-dependent reactions require energy. b. The light-dependent reactions pass electrons through an electron transport chain to the light-independent reactions. c. The light-dependent reactions produce carbon dioxide, which is then used by the light-independent reactions. d. The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.

d