A Suspension of Algae Is Incubated in a Flask in the Presence

question 219

Multiple Choice

A suspension of algae is incubated in a flask in the presence of both light and CO₂.When it is transferred to the dark, the reduction of 3-phosphoglycerate (3PG) to glyceraldehyde 3-phosphate (G3P) slows and then stops.At the same time, the concentration of ribulose 1,5-bisphosphate (RuBP) declines.Why does the RuBP concentration decline?

• A) RuBP is more rapidly metabolized in the dark.
• B) RuBP is used up in making more 3PG.
• C) Sugar is no longer generated from G3P.
• D) The levels of oxygen drop.
• E) RuBP needs to be regenerated from G3P.