Chapter 6

The light reactions of photosynthesis are said to be similar to a battery because they form a current. In which direction do the electrons of this circuit flow?

• NADP⁺ → PSII → electron transport chain → PSI → electron transport chain → NADPH

• H₂O → PSII → electron transport chain → PSI → electron transport chain → NADPH

• NADPH → PSII → electron transport chain → PSI → electron transport chain → NADP⁺

• PSI → electron transport chain → PSII → electron transport chain → NADPH

• H₂O → PSII → chlorophyll b → PSI → chlorophyll a → NADPH

The localization of the electron transport chains to the thylakoid membrane ensures that

• the energy released can be used to establish an H⁺ ion gradient.

• CO₂ remains in the stroma for the Calvin cycle reactions and does not enter the thylakoid space.

• NADP⁺ does not enter the thylakoid space.

• • the energy released is stored in the stroma.

• glyceraldehyde 3-phosphate (G3P) is produced in the thylakoid space.

Replacement electrons for the reaction center of photosystem II are derived from

• NADPH.

• NADP⁺.

• H₂O.

• CO₂.

• G3P.

Why do plants contain other pigments besides chlorophyll?

• When chlorophyll breaks down, the additional pigments can absorb the same wavelengths of light.

• Chlorophyll is unable to absorb visible light.

• When the additional pigments break down, the chlorophyll can absorb other wavelengths of light.

• The additional pigments can only absorb violet or ultraviolet light.

• The additional pigments are able to absorb other light wavelengths that chlorophyll cannot.

Which compounds link the light reactions with the Calvin cycle reactions?

• H⁺ and G3P

• G3P and NADPH

• ATP and NADPH

• G3P and ATP

• H⁺ and ATP

Sucrose, cellulose, amino acids, and starch are all made from what starter molecule in plants?

• glyceraldehyde 3-phosphate (G3P)

• glucose

• RuBP carboxylase

• ATP

• fructose

RuBP carboxylase (rubisco) is able to bind with both

• carbon dioxide and water.

• oxygen and water.

• carbon dioxide and NADPH.

• NADPH and ATP.

• carbon dioxide and oxygen.

Which steps of photosynthesis does C₄ photosynthesis partition in space?

• carbon fixation and Calvin cycle reactions

• carbon fixation and light reactions

• 1,3 bisphosphoglycerate (BPG) formation and glucose phosphate formation

• glyceraldehyde 3-phosphate (G3P) formation and glucose phosphate formation

• light reactions and Calvin cycle reactions

A new species of plant is discovered and you are asked to help classify it. Upon examination under a microscope, you find that there is a layer of bundle sheath cells containing chloroplasts around the vein of the leaf of the plant. What can you tell about the plant from this information?

• This plant very likely carries out C₄ photosynthesis.

• This plant is unlike any other plant that has ever been discovered and is a completely new category of plant.

• This plant falls into the category of CAM-type plants.

• This is a C₃ type of plant.

• This plant uses chemosynthesis rather than photosynthesis.

Chlorophyll is to the light reactions as ________ is to the Calvin cycle.

• RuBP

• NADP⁺

• carbon dioxide

• ATP

• ATP synthase