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Dark Reactions. A cyclic series of reactions that uses CO 2 , as well as the ATP and NADPH produced in the light reactions, to generate glucose Why are the dark reactions necessary?
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Dark Reactions • A cyclic series of reactions that uses CO2, as well as the ATP and NADPH produced in the light reactions, to generate glucose Why are the dark reactions necessary? • ATP and NADPH are energy storing compounds, but can only retain energy for a few minutes, therefore plants go through the dark reactions, also known as the Calvin cycle to produce a more long-term energy compound
The Dark Reactions are also known as the Calvin Cycle Calvin Cycle Reaction 1: • CO2 molecules enter the cycle from the atmosphere • These CO2 molecules combine with 5-carbon molecules inside the cell • Occurs slowly, so there is an enzyme rubisco that helps catalyze the reaction • The result is two 3-carbon molecules
Calvin Cycle Reactions 2 & 3: • Using the energy released from breaking ATP into ADP and NADPH into NADP+, the newly produced 3-carbon molecules are converted into PGAL • PGAL is phosphoglyceraldehyde • Most PGAL molecules are recycled, but 1 in 6 will be used to make glucose
Dark Reactions Summary • Uses: NADPH, ATP, and CO2 • Produces: glucose (C6H12O6) which is a source of food/energy for the plant
