The dark stage is also known as which of the following?

• A. Light independent stage
• B. Light dependent stage
• C. Both stages
• D. Dark stage

Answer: (A)

In photosynthesis, one part uses light to generate energy carriers, while the other part uses those carriers to fix carbon into sugars. The dark stage refers to reactions that don’t require light directly, because they run on ATP and NADPH produced by the light reactions. The proper name for this phase is the light independent stage, since it can proceed without light once those energy carriers are available. It’s also known as the Calvin cycle, the pathway that fixes carbon dioxide into sugar. The term dark stage is less precise because these reactions can occur even when light is present, as long as the energy from the light reactions is there.