Deck 11: Phototrophic Energy Metabolism: Photosynthesis

Question 1

Each of the following is true regarding bacterial anoxygenic photosynthesis except

A)O₂ is released.
B)Hydrogen sulfide or thiosulfate can act as electron donors.
C)Bacteriochlorophyll b absorbs light energy in the far red range of the light spectrum.
D)Electron flow is coupled to unidirectional proton pumping across the bacterial plasma membrane.
E)Following electron flow,the electron is transferred from cytochrome c to bacteriochlorophyll b .

Answer 1

O₂ is released.

Question 2

Most reactions involving NADP⁺ are ________ reactions,whereas most reactions involving NAD⁺ are ________ reactions.

A)anabolic; catabolic
B)catabolic; anabolic
C)metabolic; anabolic
D)anabolic; both catabolic and anabolic
E)both catabolic and anabolic; catabolic

Answer 2

A

Question 3

Each of the following is part of the energy transduction from solar energy to chemical energy except

A)light absorption by chlorophyll.
B)electron flow through an electron transport system.
C)unidirectional proton pumping across a membrane.
D)an electrochemical proton gradient.
E)All are involved in the energy transduction.

Answer 3

E

Question 4

The plastids that give flowers and fruits their distinctive colors are

A)chloroplasts.
B)elaioplasts.
C)amyloplasts.
D)chromoplasts.
E)proteinoplasts.

Question 5

The Emerson enhancement effect

A)explains the lack of O₂ release during anoxygenic photosynthesis.
B)results from the activity of three photosystems.
C)explains the synergistic effect of two wavelengths of light on photosynthesis.
D)makes it possible for plants to avoid the glyoxylate pathway.
E)accounts for the major difference between C₃ and C₄ plants.

Question 6

Carbon dioxide generally enters a plant through pores called

A)mesophylls.
B)stomata.
C)cuticles.
D)connexons.
E)bacteriochlorophylls.

Question 7

In a chloroplast,the stroma is

A)a pore in the outer membrane.
B)a stack of thylakoids.
C)the region between in the inner and outer membranes.
D)a connection between the grana.
E)a gel-like matrix between the inner chloroplast membrane and the thylakoid membrane.

Question 8

Which of the following is not an accessory pigment used to absorb photons that cannot be captured by chlorophyll?

A)β-carotene
B)phycoerythrin
C)lutein
D)phycochlorophyll
E)phycocyanin

Question 9

Which of the following initially traps solar energy in the process of photosynthesis?

A)water
B)chlorophyll
C)triose phosphate
D)NADP⁺
E)ATP

Question 10

Photoheterotrophs are best described as organisms that obtain energy to make ATP

A)from organic compounds but use sunlight to produce carbon sources.
B)and organic compounds from sunlight.
C)from sunlight but cannot make organic compounds from CO₂.
D)from NADH.
E)from organic compounds.

Question 11

The process by which photosynthetic organisms use light energy for ATP production is known as

A)photorespiration.
B)photosynthesis.
C)phototaxis.
D)photophosphorylation.
E)photoreduction.

Question 12

The relationship between photosystem I (PSI)and photosystem II (PSII)is correctly described by which of the following statements?

A)PSI precedes PSII in photosynthesis.
B)Electrons are excited by PSI or PSII,but not both.
C)Chlorophyll molecules in the reaction centers of PSI and PSII are designated P700 and P680,respectively,to reflect the wavelengths of their light absorption maxima.
D)PSII was discovered before PSI.
E)Only PSI contains a special pair of chlorophyll a molecules.

Question 13

Having various types of chlorophylls and accessory pigments for the photosynthetic process

A)allows for a variation in color among plants.
B)allows many wavelengths of light to be captured to provide energy for photosynthesis.
C)allows light to be harvested specifically in a stepwise manner.
D)shifts the equilibrium of photosynthesis toward the formation of products.
E)increases the efficiency of the Calvin cycle.

Question 14

The ATP synthase complex associated with the thylakoid membrane

A)contains a CF₁ proton channel and a CF_o ATPase complex.
B)is identical to the F_oF₁ complex of mitochondria.
C)performs photophosphorylation in oxygenic phototrophs.
D)is a soluble enzyme complex peripherally associated with PSI.
E)accepts electrons from PSI.

Question 15

Which of the following pigments enables red algae to utilize the dim light that penetrates ocean surface water as a source of energy?

A)chlorophyll a
B)chlorophyll c
C)lutein
D)phycoerythrin
E)?-carotene

Question 16

When a photon is absorbed by a pigment (light-absorbing molecule),such as chlorophyll,the energy of the photon is transferred to

A)D1 protein to activate PSII.
B)ATP synthase to make ATP.
C)an electron to move it from a low to a high energy orbital.
D)Plastocyanin to be passed on to PSI.
E)NADP⁺ to make NADPH.

Question 17

Of the following plastids,which is not paired with its proper function?

A)amyloplasts; sugar synthesis
B)chromoplasts; contain non-chlorophyll pigment that give flowers distinctive colors
C)chloroplasts; photosynthesis
D)proteinoplasts; protein storage
E)elaioplasts; lipid storage

Question 18

The plastoquinol (Q₈H₂)transfers electrons from

A)cytochrome b₆/f to PSII.
B)PSII to the cytochrome b₆/f complex.
C)water to PSII.
D)light harvesting complex II to PSII.
E)cytochrome b₆/f to plastoquinone.

Question 19

Plastocyanin (PC)

A)is a mobile electron carrier.
B)is functionally similar to plastoquinol.
C)carries only one electron at a time.
D)carries electrons to PSI.
E)All of the above are true of PC.

Question 20

The endosymbiont theory states that chloroplasts originated

A)by spontaneous generation in the cytoplasm of an ancestral cell.
B)by fusion of several prokaryotes.
C)from cyanobacteria entering and remaining in the cytoplasm of another cell.
D)by fusion of mitochondria and peroxisomes.
E)through evolutionary change in a mitochondrion.

Question 21

In crassulacean acid metabolism (CAM)plants

A)stomata open during the day.
B)malate is stored in large vacuoles.
C)CO₂ is transported directly into mesophyll cells.
D)the amount of carbon assimilated for each water molecule transpired is only 25 percent of that in C₃ plants.
E)carboxylation and decarboxylation reactions occur in the same location at the same time.

Question 22

Based on the comparisons of anoxygenic and oxygenic photosynthesis,the entry of oxygen into the atmosphere is most directly attributed to

A)PSI activity.
B)Calvin cycle activity.
C)photophosphorylation.
D)Hatch-Slack pathway activity.
E)Q cycle activity.

Question 23

In the Calvin cycle,the enzyme that catalyzes the capture of carbon dioxide and the formation of 3-phosphoglycerate is

A)phosphoglycerokinase.
B)ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco).
C)triose phosphate isomerase.
D)ferredoxin-NADP⁺ reductase.
E)glyceraldehyde-3-phosphate dehydrogenase.

Question 24

Each of the following statements accurately describes the Calvin cycle except

A)It is found in all oxygenic and most anoxygenic phototrophs.
B)Carbon dioxide is fixed by reduction to form organic sugars.
C)Its products enter a variety of metabolic pathways including sugar and starch biosynthesis.
D)It involves ribulose-1,5-bisphosphate (RuBP).
E)It is confined to the cytoplasm in plants and algae.

Question 25

Each of the following is an essential feature of electron transfer from water to NADP⁺ except

A)PSII.
B)PSI.
C)coenzyme Q.
D)plastocyanin (PC).
E)cytochrome b_6/f complex.

Question 26

Which of the following is the site of photosynthesis in cyanobacteria?

A)peroxisomes
B)mitochondria
C)photosynthetic membranes
D)outer walls
E)thylakoid lumens

Question 27

The transfer of energy directly from a photoexcited electron in a pigment molecule to another electron in an adjacent pigment molecule occurs by

A)photoexcitation.
B)photochemical reduction
C)photophosphorylation.
D)resonance energy transfer.
E)photorespiration.

Question 28

The Calvin cycle occurs in the chloroplast

A)stroma.
B)grana.
C)thylakoid lumen.
D)thylakoid membrane.
E)outer membrane.

Question 29

Which of the following types of organisms makes use of the Hatch-Slack cycle?

A)algae
B)C₃ plants
C)C₄ plants
D)cyanobacteria
E)photosynthetic bacteria

Question 30

Continuous carbon assimilation in the Calvin cycle is made possible by the regeneration of

A)glyceraldehyde-3-phosphate.
B)dihydroxyacetone phosphate.
C)ribulose-1,5-bisphosphate.
D)glycerate-1,3-bisphosphate.
E)3-phosphoglycerate.

Question 31

Which three organelles are involved in the glycolate pathway?

A)lysosome,chloroplast,rough endoplasmic reticulum
B)mitochondrion,nucleus,lysosome
C)peroxisome,smooth endoplasmic reticulum,chloroplast
D)peroxisome,chloroplast,mitochondrion
E)Golgi complex,peroxisome,lysosome

Question 32

Which of the following statements correctly describes cyclic electron flow pathways?

A)Water molecules are split.
B)Both PSI and PSII are required.
C)Proton gradients are never formed.
D)No exogenous electron source is required.
E)O₂ is released.

Question 33

C₃ and C₄ plants get their classification from the number of carbons in the first detectable product of carbon dioxide fixation.The C₃ product is ________,whereas the C₄ product is ________.

A)glycerol; malate
B)triose phosphate; oxaloacetate
C)3-phosphoglycerate; malate
D)ribose; phosphoenolpyruvate
E)3-phosphoglycerate; oxaloacetate

Question 34

Each of the following compounds is a source of electrons for anoxygenic photosynthesis except

A)S^2- (sulfide).
B)S₂O₃^2- (thiosulfate).
C)H2O (water).
D)succinate.
E)All of the above are sources of electrons for anoxygenic photosynthesis.

Question 35

When energy captured by antenna pigments of LHCII is funneled to the reaction center it changes the reduction potential of a P680 chlorophyll a molecule to ________,making it a better electron ________.

A)−0.80 V; donor
B)−0.80 V; acceptor
C)+0.80 V; donor
D)+0.80 V; acceptor
E)None of the above are correct.

Question 36

Which molecule in the Calvin cycle is used to synthesize starch and sucrose?

A)3-phosphoglycerate
B)glyceraldehyde-3-phosphate
C)ribulose-1,5-bisphosphate
D)1,3-bisphosphoglycerate
E)ribulose-5-phosphate

Question 37

Each of the following can be used in the Calvin cycle except

A)phosphoglycolate.
B)NADPH.
C)3-phosphoglycerate.
D)CO₂.
E)ribulose-1,5-bisphosphate.

Question 38

Bacteriochlorophyll differs from chlorophyll a and b in structure and function.Which of the following statements correctly contrasts these types of chlorophyll?

A)Bacteriochlorophyll has a heme ring,but chlorophyll a and b each have a porphyrin ring.
B)Chlorophyll a and b each have a phytol side chain,which is missing from bacteriochlorophyll.
C)Chlorophyll a has a methyl group attached to the porphyrin ring,but bacteriochlorophyll has a formyl group.
D)Bacteriochlorophyll has a saturated carbon-carbon bond at one location in the porphyrin ring that is not saturated in chlorophyll a and b.
E)Chlorophyll a and b porphyrin rings bind Mg²⁺,but the bacteriochlorophyll ring binds Fe³⁺.

Question 39

Your house plant is growing slowly and lacks its normal bright green color,so you call a botanist for advice.She suggests that the plant may be deficient in magnesium (Mg²⁺).Why are these symptoms associated with Mg²⁺ deficiency?

A)Mg²⁺ is important in the structure of many amino acids.
B)Lack of Mg²⁺ in the soil allows pathogenic bacteria to grow.
C)Mg²⁺ is a cofactor for NADPH function.
D)Mg²⁺ is an important component in chlorophyll.
E)Cytochromes require Mg²⁺ to function properly.

Question 40

Biosynthesis of sucrose occurs in the

A)cytosol.
B)stroma.
C)thylakoid lumen.
D)chloroplast intermembrane space.
E)vacuole.

Question 41

The highest intensity of the Sun's radiation at the Earth surface is in the visible light wavelength ranges of between ~400 to 700 nm.
Questions:
a)Explain how plants maximize the uptake of sunlight energy.In your answer,consider chlorophyll and antenna pigment structures and functions.
b)Why does the photosynthetic part of plants appear green?
c)The leaves of some plants lose their green color in the fall,often appearing red or yellow.Use your knowledge of plant pigments to propose a possible reason for these color changes.

Question 42

________ organisms such as green and purple bacteria derive electrons from sulfide,thiosulfate,and succinate to generate NADPH.

Question 43

________ proteins stabilize the arrangement of the chlorophyll within a photosystem and modify the absorption spectra of specific chlorophyll molecules.

Question 44

When atmospheric CO₂ concentrations decrease,the ________ cycle gives C₄ plants an advantage over C₃ in carbon fixation.

Question 45

The light-dependent generation of NADPH is referred to as ________.

Question 46

Plastocyanin (PC)is a copper-containing protein that,like plastoquinol,is a mobile ________ carrier in photosynthesis.

Question 47

Some herbicides,such as paraquat,cause oxidation of NADPH to NADP⁺.How does paraquat interfere with plant energy metabolism?

Question 48

Crassulacean acid metabolism (CAM)plants open their stomata only during the ________ to minimize water loss.

Question 49

3-phosphoglycerate is to C₃ plants as ________ is to C₄ plants.

Question 50

Light behaves as a stream of discrete particles called ________,each carrying a ________ (indivisible packet)of energy.

Question 51

Chlorophyll is comprised of a central ________ containing a(n)________ ion and a(n)________ side chain.

Question 52

Each of the following directly regulates the Calvin cycle activity to ensure maximum efficiency except

A)stromal pH.
B)Mg²⁺ concentration.
C)chlorophyll photon absorption.
D)NADPH concentration.
E)ATP concentration.

Question 53

Diatoms have both chlorophyll a and chlorophyll ________.

Question 54

There has been and remains great interest in developing safe and effective herbicides.In some situations,it would be desirable to have a herbicide that killed a wide variety of different plants,but in other cases it would be best to have a herbicide that was much more selective.
a)What plant activity would you target to kill the widest variety of plants?
b)What plant activity would you target to kill C₄ plants?
c)What plant activity would you target to kill CAM plants?
Be as specific as possible.

Question 55

The Calvin cycle in C₃ plants occurs in ________ cells,whereas the Calvin cycle in C₄ plants occurs in the ________.

Question 56

Rubisco is an important enzyme in the Calvin cycle because it acts as a carboxylase to catalyze addition of carbon dioxide and water to ribulose-1,5-bisphosphate,which then forms two molecules of 3-phosphoglycerate.Rubisco also acts as an oxygenase to catalyze addition of molecular oxygen rather than carbon dioxide to ribulose-1,5-bisphosphate.
a)What is (are)the product(s)of the rubisco oxygenase reaction activity and why is this a problem for plants?
b)Explain why rubisco's much lower affinity for oxygen than for carbon dioxide does not mitigate the rubisco oxygenase problem for plants.
c)Identify the pathway plants use to metabolize the problematic product of rubisco oxygenase and the final fate of its carbons.
d)Explain why the oxygenase activity of rubisco is particularly problematic for plants in arid environments.
e)What strategies do plants in arid environments use to deal with this problem?

Question 57

The energy transduction reactions of photosynthesis convert solar energy into chemical energy in the form of ________ and ________.

Question 58

The glycolate pathway performs the process of ________ by consuming O₂ and releasing CO₂ in a light-dependent manner.