SHTB bài 5

Multiple Choice

What happens to the free energy released as electrons are passed from photosystem II to photosystem I through a series of electron carriers?

• It excites electrons of the reaction center in photosystem I.

• It is used to synthesize ATP through substrate-level phosphorylation.

• It is used to establish and maintain a proton gradient.

• It is used to phosphorylate NAD+ to NADPH.

Multiple Choice

Use the following figure to answer the question:  If photosynthesizing green algae are provided with CO2 containing heavy oxygen (18-O), which of the following molecules produced by the algae (refer to the accompanying figure) will fail to contain 18-O in later biochemical analyses?

• 3-phosphoglycerate

• ADP

• ribulose bisphosphate (RuBP)

• glyceraldehyde 3-phosphate (G3P)

Multiple Choice

Which of the following processes occurs during the Calvin cycle?

• regeneration of the CO2 acceptor

  
  

• reduction of NADPH

• release of oxygen

• production of ATP

Multiple Choice

To identify the molecule that accepts CO2, Calvin and Benson manipulated the carbonfixation 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?

• The CO2 acceptor concentration would increase when the CO2 is cut off, but decrease when the light is cut off.

  
  

• The CO2 acceptor concentration would decrease when either the CO2 or light are cut off.

• The CO2 acceptor concentration would decrease when the CO2 is cut off, but increase when the light is cut off.

• The CO2 acceptor concentration would increase when either the CO2 or light are cut off.

Multiple Choice

Which process is most directly driven by light energy?

• transfer of energy from pigment molecule to pigment molecule

• creation of a pH gradient by pumping protons across the thylakoid membrane

• ATP synthesis

• reduction of NADP+ molecules

Multiple Choice

Which of the following sequences correctly represents the flow of electrons during photosynthesis?

• NADPH → chlorophyll → photosystem I → Calvin cycle

• H2O → plastoquinone → cytochrome b6-f → plastocyanin → ferredoxin → NADPH → Calvin cycle

• NADPH → O2 → plastoquinone → CO2

• NADPH → electron transport chain → O2

Multiple Choice

Which of the following molecules are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

• CO2 and glucose

• H2O and O2

• ADP, Pi, and NADP+

• ATP and NADPH

Multiple Choice

In mitochondria, an electron transport chain pumps protons from the matrix into the intermembrane space, whereas in chloroplasts, an electron transport chain pumps protons from the ________.

• thylakoid space to the stroma

• stroma to the thylakoid space

• thylakoid space to the matrix

• matrix to the stroma

Multiple Choice

A flask containing photosynthetic green algae and a control flask containing water with no algae are both placed under a bank of lights that is set to cycle between 12 hours of light and 12 hours of dark. The dissolved oxygen concentrations in both flasks are monitored. Predict what the relative dissolved oxygen concentrations will be in the flask with algae compared to the control flask. The dissolved oxygen in the flask with algae will ________.

• be higher in the light, but lower in the dark

• always be lower

• be higher in the light, but the same in the dark

• always be higher

Multiple Choice

In which of the following organisms did the process of photosynthesis most likely originate?

• in fungi

• in prokaryotes

• in plants

• three separate times during evolution

Multiple Choice

Which molecule is the final electron acceptor for electrons from photosystem I?

• NADP+

• oxygen

• chlorophyll in photosystem II

• carbon dioxide

Multiple Choice

As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in one hour. You find that 30,000 molecules of ATP were consumed, but only 20,000 molecules of NADPH were consumed. What is the source of the extra ATP molecules?

• linear electron flow

• cyclic electron flow

• photosystem II

• photosystem I

Multiple Choice

What are the products of cyclic electron flow during the light reactions of photosynthesis?

• heat and fluorescence

• ATP and NADPH

• ATP

• ADP and NADP+

Multiple Choice

The mechanism of photophosphorylation is most similar to which of the following processes?

• substrate-level phosphorylation in glycolysis

• the Calvin cycle

• reduction of NADP+

• oxidative phosphorylation in cellular respiration

Multiple Choice

Which of the following events are associated with chemiosmosis in chloroplasts?

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• The pH of the stroma increases and ATP is synthesized.

• The pH of the stroma decreases and ATP is hydrolyzed

• The pH of the thylakoid space increases and ATP is synthesized.

• The pH of the cytoplasm outside the chloroplast decreases and ATP is synthesized

Multiple Choice

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?

• green

• orange

• Any color will work equally well.

• blue

Multiple Choice

What are the products of linear electron flow during the light reactions of photosynthesis?

• ATP and NADPH

• heat and fluorescence

• ATP and P700

• ADP and NADP+

Multiple Choice

The oxygen released by photosynthesis is produced by which of the following processes?

• the electron transfer system of photosystem II

• splitting water molecules

• the electron transfer system of photosystem I

• chemiosmosis

Multiple Choice

Which of the following processes is most directly driven by light energy?

• carbon fixation in the stroma

• removal of electrons from chlorophyll molecules

• reduction of NADP+ molecules

• creation of a pH gradient by pumping protons across the thylakoid membrane

Multiple Choice

When a molecule of chlorophyll in an antenna complex absorbs a photon, the excited electron is rapidly transferred from one chlorophyll molecule to another until it reaches the photochemical reaction center.

• true

• false

Multiple Choice

Which of the following processes is directly associated with photosystem I?

• generation of molecular oxygen

• receiving electrons from the thylakoid membrane electron transport chain

• passing electrons to NADP+ ( chat GPT)

• extraction of hydrogen electrons from the splitting of water

Multiple Choice

Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. Which of the following approaches would be the best way to detect the lack of photosystem II in these organisms?

• Determine whether they produce O2 in the light.

• Determine the action spectrum for photosynthesis in these organisms.

• Determine whether they consume CO2 in the dark.

• Determine whether they have thylakoid membranes.

Multiple Choice

Under what conditions do photosynthesis and cellular respiration occur in plants?

• Photosynthesis and cellular respiration occur only in the light.

• Photosynthesis occurs only in the light, and cellular respiration occurs only in the dark

• Photosynthesis and cellular respiration occur in both the dark and the light.

• Photosynthesis occurs only in the light, and cellular respiration occurs in both the dark and the light.

Multiple Choice

Which of the following events accompanies absorption of energy by chlorophyll molecules of the reaction-center complex?

• ATP is synthesized from the energy absorbed.

• NADP+ is reduced to NADPH.

• An electron is excited.

• A molecule of water is split.

Multiple Choice

In photosynthetic cells, synthesis of ATP by chemiosmosis occurs during ________.

• photosynthesis only

• respiration only

• photosynthesis, respiration, and fermentation

• photosynthesis and respiration

Multiple Choice

In the initial step in carbon fixation, a molecule of CO2 is attached to RuBP to produce a six-carbon molecule, which is immediately split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to occur to complete the Calvin cycle?

• regeneration of ATP from ADP

• addition of a pair of electrons from NADPH

• regeneration of NADP+

• regeneration of RuBP

Multiple Choice

 What is the relationship between the wavelength of light and the quantity of energy per photon?

• They are separate phenomena.

• They are inversely related.

• They have a direct, linear relationship.

• They are logarithmically related.

Multiple Choice

Which of the following processes would be most directly affected if a thylakoid membrane is punctured so that the interior of the thylakoid is no longer separated from the stroma?

• splitting of water

• synthesis of ATP

• reduction of NADP+

• flow of electrons from photosystem II to photosystem I

Multiple Choice

Chlorophyll P680+ is said to be the strongest biological oxidizing agent. Given its function, why is this necessary?

• It transfers its electrons to reduce NADP+ to NADPH.

• It is the receptor for the most excited electron in either photosystem of photosynthesis.

• It is the molecule that transfers electrons to plastoquinone (Pq) of the electron transfer system.

• It obtains electrons from the oxygen atom in a water molecule, so it must have a stronger attraction for electrons than oxygen has.

Multiple Choice

In autumn, chlorophyll is degraded in the leaves of deciduous trees. Why do the leaves change color to shades of yellow, orange, or red?

• Other pigments such as carotenoids are still present in the leaves.

• Sugars from sap fill the leaves prior to winter.

• Degraded chlorophyll changes into many other colors.

• In the absence of photosynthesis, the leaves produce energy exclusively by aerobic cellular respiration.

Multiple Choice

What is the function of the pigment molecules in a light-harvesting complex in the thylakoid membranes?

• They split water and release oxygen from the reaction-center chlorophyll.

• They absorb and transfer light energy to the reaction-center chlorophyll.

• They synthesize ATP from ADP and Pi.

• They transfer electrons to NADP+

Multiple Choice

Part of a photosystem that captures light energy and channels it into the photochemical reaction center.

• photosynthetic electron transfer

• antenna complex

• stroma

• photochemical reaction center

Multiple Choice

In a plant, which of the following reactions produce molecular oxygen (O2)?

• the Calvin cycle alone

• neither the light reactions nor the Calvin cycle

• the light reactions and the Calvin cycle

• the light reactions alone

Multiple Choice

Where are ATP synthase complexes located in plant cells?

• thylakoid membrane and plasma membrane

• thylakoid membrane only

• thylakoid membrane and inner mitochondrial membrane

• inner mitochondrial membrane only