During photosynthesis the enzyme RuBisCO does the work of reducing carbon dioxide from the atmosphere. It is reacted with a molecule of ribulose-1,5-bisphosphate anion, which has a 5-carbon backbone. The resulting unstable 6-carbon compound immediately breaks down into two molecules of glycerate 3-phosphate, which is 3-carbons.
This happens during the Calvin Cycle (or the light-independent reactions or dark reactions). All the carbon chains you love, like plants, food, fuel, cats, dogs, and you, started getting linked together this way.

During photosynthesis the enzyme RuBisCO does the work of reducing carbon dioxide from the atmosphere. It is reacted with a molecule of ribulose-1,5-bisphosphate anion, which has a 5-carbon backbone. The resulting unstable 6-carbon compound immediately breaks down into two molecules of glycerate 3-phosphate, which is 3-carbons.

This happens during the Calvin Cycle (or the light-independent reactions or dark reactions). All the carbon chains you love, like plants, food, fuel, cats, dogs, and you, started getting linked together this way.