Chapter 8 Review Questions From Book

Which molecule must enter the Calvin cycle continually for the light-independent reactions to take place? RuBisCO, RuBP, 3-PGA, or CO2.

CO2.

How many photons does it take to fully reduce one molecule of NADP+ to NADPH? 1, 2, 4, or 8.

2.

Why is the third stage of the Calvin cycle called the regeneration stage?

Because RuBP, the molecule needed at the start of the cycle, is regenerated from G3P.

Which of the following structures is not a component of a photosystem? ATP Synthase, Antenna Molecule, Reaction Center, or Primary Electron Acceptor.

ATP Synthase.

Why does it take three turns of the Calvin cycle to produce G3P, the initial product of photosynthesis?

Because G3P has three carbon atoms, and each turn of the cycle takes in one carbon atom in the form of carbon dioxide.

What are the roles of ATP and NADPH in photosynthesis?

Both of these molecules carry energy; in the case of NADPH, it has reducing power that is used to fuel the process of making carbohydrate molecules in light-independent reactions.

Figure 8.18: Which of the following statements is true? 1) In photosynthesis, oxygen, carbon dioxide, ATP, and NADPH are reactants. G3P and water are products. 2) In photosynthesis, chlorophyll, water, and carbon dioxide are reactants. G3P and oxygen are products. 3) In photosynthesis, water, carbon dioxide, ATP, and NADHPH are reactants. RuBP and oxygen are products. 4) In photosynthesis, water and carbon dioxide are reactants. G3P and oxygen are products.

In photosynthesis, water and carbon dioxide are reactants. G3P and oxygen are products.

Which complex is not involved in the establishment of conditions for ATP synthesis? Photosystem I, ATP Synthase, Photosystem II, or Cytochrome Complex.

Photosystem II.

Which order of molecular conversions is correct for the Calvin cycle? RuBP + G3P --> 3-PGA --> Sugar. RuBisCO --> CO2 --> RuBP --> G3P. RuBP + CO2 --> [RuBisCO] 3-PGA --> G3P. CO2 --> 3-PGA --> RuBP --> G3P.

RuBP + CO2 --> [RuBisCO] 3-PGA --> G3P.

In which compartment of the plant cell do the light-independent reactions of photosynthesis take place? Thylakoid, Stroma, Outer Membrane, or Mesophyll.

Stroma.

Which statement correctly describes carbon fixation? 1) The conversion of CO2 into an organic compound. 2) The use of RuBisCO to form 3-PGA. 3) The production of carbohydrate molecules from G3P. 4) The formation of RuBP from G3P molecules. 5) The use of ATP and NADPH to reduce CO2.

The conversion of CO2 into an organic compound.

What is the overall outcome of the light reactions in photosynthesis?

The outcome of light reactions in photosynthesis is the conversion of solar energy into chemical energy that the chloroplasts can use to do work (mostly anabolic production of carbohydrates from carbon dioxide.

Which part of the light-independent reactions would be affected if a cell could not produce the enzyme RuBisCO?

None of the cycle could take place, because RuBisCO its essential in fixing carbon dioxide. Specifically, RuBisCO catalyzes the reaction between carbon dioxide and RuBP at the start of the cycle.

From which component of the light-dependent reactions does NADPH form most directly? Photosystem II, Photosystem I, Cytochrome Complex, or ATP Synthase.

Photosystem I

What two main products result from photosynthesis? Oxygen and Carbon Dioxide, Chlorophyll and Oxygen, Sugars/Carbohydrates and Oxygen, or Sugars/Carbohydrates and Carbon Dioxide.

Sugars/Carbohydrates and Oxygen.

Which statement about thylakoids in eukaryotes is not correct? 1) Thylakoids are assembled into stacks. 2) Thylakoids exist as a maze of folded membranes. 3) The space surrounding thylakoids is called stroma. 4) Thylakoids contain chlorophyll.

Thylakoids exist as a maze of folded membranes.

Figure 8.16: What is the source of electrons for the chloroplast electron transport chain? Water, Oxygen, Carbon Dioxide, or NADPH.

Water.

Why are carnivores, such as lions, dependent on photosynthesis to survive?

Because lions eat animals that eat plants.

Where in eukaryotic cells does the Calvin cycle take place? Thylakoid Membrane, Thylakoid Lumen, Chloroplast Stroma, or Granum.

Chloroplast Stroma.

Which of the following components is not used by both plants and cyanobacteria to carry out photosynthesis? Chloroplasts, Chlorophyll, Carbon Dioxide, or Water.

Chloroplasts.

Describe the pathway of electron transfer from Photosystem II to photosystem I in light-dependent reactions.

In the photosystem II reaction center, energy from sunlight is used to extract electrons from water. The electrons travel through the chloroplast electron transport chain to photosystem I, which reduces NADP+ to NADPH.

Figure 8.6: On a hot, dry day, plants close their stomata to conserve water. What impact will this have on photosynthesis?

Levels of carbon dioxide (a necessary photosynthetic substrate) will immediately fall. As a result, the rate of photosynthesis will be inhibited.

Why are energy carriers thought of as either "full" or "empty"?

The energy carriers that move from the light-dependent reaction to the light-independent one are "full" because they bring energy. After the energy is released, the "empty" energy carriers return to the light-dependent reaction to obtain more energy. There is not much actual movement involved. Both ATP and NADPH are produced in the storm where they are used and reconverted into ADP, Pi, and NADP+.