8.3 The Calvin cycle makes sugar from carbon dioxide

Summary:

Trip Around the Calvin Cycle

• The starting material of Calvin cycle is regenerated each time the process occurs
• The starting material that gets regenerated is RubP
• Inputs of Calvin cycle: carbon dioxide from the air, ATP and NADPH produced by light reactions
• Output of Calvin cycle: an energy-rich sugar molecule, which is G3P
• G3P is the raw material used by plant cells to make glucose and other organic molecules

Summary of Photosynthesis

• Equation: 6CO2 + 6H2O - - - 6C6H12O6 + 6O2
• Light reacion converts light energy to the chemical energy of ATP and NADPH in the thylakoid membranes
• Calvin cycle uses ATP and NADPH to convert carbon dioxide to sugar in the stroma
• Photosynthesis is the first step in the flow of energy through an ecosystem
• Photosynthesis is the ultimate source of all the food you eat and all the oxygen you breathe

Concept Check:

1. Inputs are carbon dioxide from the air, ATP and NADPH produced by light reactions, outputs are G3Ps, which are rich-sugar molecules.
2. Light reaction. The Calvin cycle.
3. It's called a cycle because the starting material is regenerated each time the process occurs.
4. Sugar, and plant use it to build other organic molecules.