Which chemical compounds serve as starting materials, and which are the products of photosynthesis?

The starting materials for photosynthesis – carbon dioxide entering the leaves from the air and water – are the products of the complete oxidation of carbon (CO2) and hydrogen (H2O). In organic substances formed during photosynthesis, carbon is in a reduced state. During photosynthesis, the СО2 – Н2О system, consisting of oxidized substances and located at a low energy level, is restored to a less stable СН2О – 02 system, which is at a higher energy level.