How does the Calvin Cycle work?

The Calvin Cycle converts hydrogen and carbon dioxide into glucose and water.

The Calvin Cycle is also known as the dark reaction or reduction of carbon dioxide. It is the second part of (the first being Hill reaction/light reaction/photolysis of water) and occurs both when there is light and when it is dark. This cycle takes place in the stroma of chloroplasts. Nevertheless, it needs to receive substances from the light reaction (ATP and hydrogen atoms) in order to take place.

The Calvin Cycle begins when ATP molecules and hydrogen atoms move to the stroma after the light reaction. The ATP molecules supply energy and the H atoms reducing power.

H atoms are used to reduce carbon dioxide into glucose. This can be represented by the following chemical equation:

24H + 6CO2 → 6(CH2O) + 6H2O

The six units of CH2O combine to form one molecule of glucose.

At the end of the reaction, glucose and water are produced. The glucose, which are monomers of , undergo condensation to form starch. The starch is temporarily stored as starch granules in the chloroplast.

Hope this helps! :)