Cell bio ch. 11 Flashcards

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

A. from organic compounds but use sunlight to produce carbon sources.

B. from some forms of chemicals.

C. from sunlight but cannot make organic compounds from CO₂.

D. from organic compounds.

E. and organic compounds from sunlight.

Carbon dioxide generally enters the plant through pores called

A. stomata.

B. connexons.

C. bacteriochlorophylls.

D. mesophyll.

E. the cuticle.

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

A. photoligase

B. photophosphorylation.

C. photorespiration.

D. phototaxis.

E. photosynthesis.

The endosymbiotic theory states that mitochondria originated from

A. a long, intense period of lightning.

B. the slow evolution of various organelles over millions of years, particularly during the time of the dinosaurs.

C. the fusion of several prokaryotes.

D. a routine step in evolution.

E. purple bacteria entering and remaining in the cytoplasm of another cell.

All of the following are true regarding anoxygenic photosynthesis except

A. it is a light-driven oxidation-reduction process.

B. absorbed light energy is typically in the near ultraviolet and far red ranges of the light spectrum.

C. NADPH is regenerated by photoreduction.

D. a water molecule is split.

E. sulfide or thiosulfate can act as electron donors.

In a chloroplast, the stroma is the

A. region between in the inner and outer membranes.

B. stack of thylakoids.

C. central semifluid region.

D. connection between the grana.

E. cytochromes associated with the thylakoids.

The proplastids associated with giving flowers and fruits their distinctive colors are the

A. plastids.

B. chromoplasts.

C. amyloplasts.

D. chloroplasts.

E. elaioplasts.

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

A. a phycobilin

B. beta-carotene

C. lutein

D. phycochlorophyll

E. phycocyanin

What is the advantage to having various types of chlorophylls and accessory pigments for the photosynthetic process?

A. It allows for a variation in color amongst plants.

B. It allows for light in many wavelengths to be utilized for photosynthesis.

C. It allows light to be harvested specifically in a step-wise manner.

D. It shifts the equilibrium of photosynthesis toward the formation of products.

E. It allows light to be harvested specifically in a step-wise manner and it shifts the equilibrium of photosynthesis toward the formation of products.

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

A. chlorophyll

B. triose phosphate

C. water

D. ATP

E. NADP⁺

Which of the following pigments is found exclusively in red algae?

A. β-carotene

B. phycoerythrin

C. chlorophyll c

D. lutein

E. chlorophyll a

NADPH contains the pentose sugar ________ and the nitrogenous base ________.

A. ribose; adenine

B. glucose; thymine

C. deoxyribose; nicotinamide

D. deoxyribose; cytosine

E. ribose; nicotinamide

NADP⁺ is the coenzyme of choice in ________ reactions, while NAD⁺ is the coenzyme of choice in ________ reactions.

A. catabolic; anabolic

B. anabolic; catabolic

C. metabolic; anabolic

D. both catabolic and anabolic; catabolic

E. anabolic; both catabolic and anabolic

Which of the following statements correctly characterizes the relationship between NADP⁺/NADPH and NAD⁺/NADH?

A. Only NAD⁺/NADH is used to transport electrons and protons.

B. Both are used extensively during photosynthesis in oxygenic phototrophs.

C. Neither are helpful to oxygenic phototrophs.

D. NADP⁺/NADPH is used primarily for catabolic reactions.

E. NADP⁺/NADPH has an extra phosphate compared to NAD⁺/NADH.

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

A. PSI is designated P700, whereas PSII is designated P680.

B. Electrons are excited by PSI or PSII, but not both.

C. PSI absorbs only short wavelengths of light.

D. The absorption maximum of PSI is 680 nm.

E. The absorption maximum of PSII is 700 nm.

Plastocyanin (PC)

A. is a mobile electron carrier.

B. is also called plastoquinol.

C. carries only a single electron at a time.

D. is a mobile electron carrier and carries only a single electron at a time.

E. is a mobile electron carrier, it is also called plastoquinol and it carries only a single electron at a time.

Plastoquinol transfers electrons from

A. cytochrome b_6/f to plastiquinone.

B. photosystem II to photosystem I.

C. light harvesting complex II to photosystem II.

D. water to photosystem II.

E. cytochrome b_6/f complex to coenzyme Q

The ATP synthase complex in the thylakoid membrane

A. is identical to the F_oF₁ complex of mitochondria.

B. performs photophosphorylation in oxygenic phototrophs.

C. contains an assembly of hydrophobic polypeptides that function in ATP synthesis.

D. contains an embedded CF₁ component and a protruding CF_o component.

E. all of the above

Which of the following is not an essential feature of electron transfer from water to NADP⁺?

A. photosystem II complex

B. plastocyanin (PC)

C. coenzyme Q

D. cytochrome b_6/f complex

E. photosystem I complex

The transfer of energy from a photoexcited electron to another electron of an adjacent pigment molecule is known as

A. photophosphorylation.

B. quantum leap.

C. resonance energy transfer.

D. photorespiration.

E. photoexcitation.

A house plant seems to be growing slowly and lacks its normal bright green color. 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. Cytochromes require Mg²⁺ to function properly.

D. Mg²⁺ is required before NADPH can function.

E. Mg²⁺ is an important component in chlorophyll.

Which of the following minerals are directly involved with light absorption in photosynthesis?

A. Zn

B. Na

C. Ca

D. Fe

E. Mg

Which of the following statements accurately describes the Calvin cycle?

A. It occurs in the chloroplast stroma.

B. The Calvin cycle is a means of carbon fixation.

C. It is a carbon assimilation process.

D. In this process, carbon dioxide is reduced to organic sugars.

E. all of the above

The Calvin cycle occurs in the ________ region of the chloroplast.

A. stroma

B. thylakoid lumen

C. grana

D. thylakoid membrane

E. outer membrane

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

A. triose phosphate isomerase.

B. phosphoribulokinase.

C. phosphoglycerokinase.

D. glyceraldehyde-3-phosphate dehydrogenase.

E. ribulose bisphosphate carboxylase/oxygenase (rubisco).

Which of the following statements is correct regarding cyclic photosynthetic pathways?

A. No exogenous electron source is required.

B. Proton gradients are not formed.

C. Water molecules need to be split.

D. Both PSI and PSII are required.

E. all of the above

The regeneration of what CO₂ acceptor molecule allows for continuous carbon assimilation in the Calvin cycle?

A. glycerate-1,3-bisphosphate

B. glyceraldehyde-3-phosphate

C. dihydroxyacetone phosphate

D. 3-phosphoglycerate

E. ribulose-1,5-bisphosphate

Which two triose phosphates are produced during the Calvin cycle and are the starting points for starch and sucrose synthesis?

A. dihydroxyacetone phosphate and glycerate-1,3-bisphosphate

B. 3-phosphoglycerate and glyceraldehyde-3-phosphate

C. 3-phosphoglycerate and ribulose-1,5-bisphosphate

D. dihydroxyacetone phosphate and glyceraldehyde-3-phosphate

E. ribulose-1,5-bisphosphate and glycerol phosphate

Biosynthesis of sucrose occurs in the

A. thylakoid lumen.

B. cytoplasm.

C. stroma thylakoids.

D. intermembrane space.

E. stroma.

Bacteria do not have organelles. How are they able to carry out photosynthesis?

A. They use their cell membrane to carry out photosynthesis.

B. They are parasites of plants that do have organelles.

C. 70S ribosomes function as photosystems.

D. They interact in a symbiotic relationship with eukaryotic plants.

E. DNA in the nucleoid captures solar energy.

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

A. photoreactivation.

B. bacteriorhodopsin.

C. photosystem I.

D. the Calvin cycle.

E. photosystem II.

The plants referred to as C₃ and C₄ plants get this designation based on the number of carbons in the first detectable product of carbon dioxide fixation. The C₃ product is ________, whereas the C₄ product is ________.

A. 3-phosphoglycerate; malate

B. ribose; phosphoenolpyruvate

C. 3-phosphoglycerate; oxaloacetate

D. triose phosphate; oxaloacetate

E. glycerol; malate

Which of the following products cannot be used in the Calvin cycle?

A. 3-phosphoglycerate

B. CO₂

C. phosphoglycolate

D. ribulose-1, 5-bisphosphate

E. NADPH

Which of these equations best summarizes photosynthesis?

A. 6 CO₂ + 6 O₂ → C₆H₁₂O₆ + 6 H₂O

B. H₂O → 2 H⁺ + 1/2 O₂ + 2e^-

C. C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 12 H₂O

D. 6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂

E. C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + Energy

The light reactions of photosynthesis use _____ and produce _____.

A. water ... NADPH

B. carbon dioxide ... oxygen

C. NADPH ... NADP⁺

D. NADPH ... oxygen

E. carbon dioxide ... sugar

Which process produces oxygen?

A. Cellular respiration

B. Photosynthesis

Which set of reactions uses H₂O and produces O₂?

A. The light-independent reactions

B. The light-dependent reactions

What is the importance of the light-independent reactions in terms of carbon flow in the biosphere?

A. The light-independent reactions turn sugar into ATP for energy.

B. The light-independent reactions turn CO₂, a gas, into usable carbon in the form of sugars.

C. The light-independent reactions turn glucose, a sugar, into CO₂ gas.

D. The light-independent reactions use CO₂ to make ATP.

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

A. True

B. False

Which of the following molecules is the primary product of photosystem I?

A. ATP

B. Carbon dioxide

C. NADPH

D. Oxygen

What is the biological significance of the light-independent reactions of photosynthesis?

A. They convert carbon dioxide to sugar.

B. They make oxygen.

C. They generate ATP and NADPH.

D. They convert ATP to sugar.

Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis?

A. The light-dependent reactions produce carbon dioxide, which is then used by the light-independent reactions.

B. The light-dependent reactions pass electrons through an electron transport chain to the light-independent reactions.

C. The light-independent reactions release energy, and the light-dependent reactions require energy.

D. The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.

Which of the following reactions ensures that the Calvin cycle can make a continuous supply of glucose?

A. Regneration of RuBP

B. Production of 3-phosphoglycerate

C. Carbon fixation

D. Production of G3P

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

A. photophosphorylation.

B. phototaxis.

C. photorespiration.

D. photosynthesis.

E. photoreduction.

In a chloroplast, the stroma is

A. a stack of thylakoids.

B. a pore in the outer membrane.

C. a gel-like matrix between the inner chloroplast membrane and the thylakoid membrane.

D. a connection between the grana.

E. the region between in the inner and outer membranes.

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

A. unidirectional proton pumping across a membrane.

B. light absorption by chlorophyll.

C. an electrochemical proton gradient.

D. electron flow through an electron transport system.

E. All are involved in the energy transduction.

The ATP synthase complex associated with the thylakoid membrane

A. accepts electrons from PSI.

B. performs photophosphorylation in oxygenic phototrophs.

C. contains a CF₁ proton channel and a CF_o ATPase complex.

D. is a soluble enzyme complex peripherally associated with PSI.

E. is identical to the F_oF₁ complex of mitochondria.

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

A. PSII.

B. PSI.

C. plastocyanin (PC).

D. cytochrome b _6/f complex.

E. coenzyme Q.

Biosynthesis of sucrose occurs in the

A. vacuole.

B. stroma.

C. thylakoid lumen.

D. chloroplast intermembrane space.

E. cytosol.

Which of the following explains why photosystem units contain a high proportion of antenna pigments compared to reaction centers?

A. Antenna pigments contain rubisco.

B. Antenna pigments help reduce the reaction centers.

C. Antenna pigments split water.

D. Antenna pigments allow more wavelengths of light and more photons to be captured, increasing the efficiency of light capture.

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

A. allows light to be harvested specifically in a stepwise manner.

B. shifts the equilibrium of photosynthesis toward the formation of products.

C. increases the efficiency of the Calvin cycle.

D. allows many wavelengths of light to be captured to provide energy for photosynthesis.

E. allows for a variation in color among plants.

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

A. ATP synthase to make ATP.

B. an electron to move it from a low to a high energy orbital.

C. D1 protein to activate PSII.

D. NADP⁺ to make NADPH.

E. Plastocyanin to be passed on to PSI.

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. Only PSI contains a special pair of chlorophyll a molecules.

D. PSII was discovered before PSI.

E. 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.

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

A. photophosphorylation.

B. photorespiration.

C. resonance energy transfer.

D. photoexcitation.

E. photochemical reduction

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.

The NADPH required for CO₂ fixation is produced __________.

A. in direct proportion to the amount of O₂ produced

B. by the hydrolysis of ATP

C. by the reduction of O₂

D. by cyclic photophosphorylation

Which is the correct order of flow of electrons through the thylakoid membrane during energy transduction reactions?

A. cytochrome complex, photosystem I, photosystem II

B. photosystem II, photosystem I, cytochrome complex

C. cytochrome complex, photosystem II, photosystem I

D. photosystem II, cytochrome complex, photosystem I

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

A. anabolic; both catabolic and anabolic

B. anabolic; catabolic

C. catabolic; anabolic

D. metabolic; anabolic

E. both catabolic and anabolic; catabolic

Plastocyanin (PC)

A. carries only one electron at a time.

B. is functionally similar to plastoquinol.

C. is a mobile electron carrier.

D. carries electrons to PSI.

E. All of the above are true of PC.

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

A. Q cycle activity.

B. photophosphorylation.

C. PSI activity.

D. Calvin cycle activity.

E. Hatch - Slack pathway activity.

Which process in photosynthesis will be most directly compromised by inhibition of the cytochrome b ₆ f complex?

A. water splitting

B. carbon dioxide fixation

C. NADP⁺ reduction

D. proton pumping

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

A. No exogenous electron source is required.

B. Proton gradients are never formed.

C. Both PSI and PSII are required.

D. O₂ is released.

E. Water molecules are split.

Carbon fixation involves the addition of carbon dioxide to _____.

A. RuBP

B. NADPH

C. Rubisco

D. G3P

E. 3-PGA

After 3-PGA is phosphorylated, it is reduced by _____.

A. ADP

B. ATP

C. NADPH

D. NADP⁺

E. CO₂

How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?

A. 6

B. 8

C. 2

D. 10

E. 4

In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?

A. 3

B. 5

C. 2

D. 1

E. 4

The reactions of the Calvin cycle are NOT directly dependent on light, but they usually do NOT occur at night. Why?

A. Carbon dioxide concentrations decrease at night.

B. The Calvin cycle depends on ATP and NADPH, which are most readily available from the light reactions.

C. It is often too cold at night for these reactions to take place.

D. Plants usually open their stomata at night.

Which of the following enzymes represents the link between the light and dark reactions of photosynthesis?

A. photosystem I

B. rubisco

C. ferredoxin-NADP⁺ reductase

D. photosystem II

Each of the following statements accurately describes the Calvin cycle except

A. It involves ribulose-1,5-bisphosphate (RuBP).

B. It is found in all oxygenic and most anoxygenic phototrophs.

C. Carbon dioxide is fixed by reduction to form organic sugars.

D. It is confined to the cytoplasm in plants and algae.

E. Its products enter a variety of metabolic pathways including sugar and starch biosynthesis.

The Calvin cycle occurs in the chloroplast

A. thylakoid lumen.

B. grana.

C. outer membrane.

D. thylakoid membrane.

E. stroma.

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

A. ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco).

B. ferredoxin-NADP⁺ reductase.

C. phosphoglycerokinase.

D. glyceraldehyde-3-phosphate dehydrogenase.

E. triose phosphate isomerase.

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

A. 3-phosphoglycerate.

B. glyceraldehyde-3-phosphate.

C. dihydroxyacetone phosphate.

D. ribulose-1,5-bisphosphate.

E. glycerate-1,3-bisphosphate.

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

For which of the following reasons should glucose NOT be considered a primary product of photosynthesis?

A. The carbon fixation reactions fix one CO₂ at a time, not six.

B. The first reduced sugar formed is 3-phosphoglyceraldehyde (3 carbons).

C. Starch is the storage form of fixed carbon.

D. All of the answers are correct.