there are 2 stages in photosynthesis
light stage and dark stage
light stage takes placein the grana because there's presence of chlorophyll. 2 reactions take place here.
1. photolysis of water where water molecules are split into hydrogen ions and oxygen gas in presence of chlorophyll and oxygen gas. the oxygen gas is released into the atmosphere but hydrogen ions are used in dark stage.
2. formation of adenosine triphosphate which is formed by combination of adenosine diphosphate and an inorganic phosphate in presence of light. this adenosine triphosphate is also used in dark stage
dark stage is a light independent stage which takes place in the stroma. energy is provided by adenosine triphosphate formed in the light stage. this stage involves tge combination of carbon(iv)oxide and hydrogen ions to form a simple carbohydrate and a water molecule. this process is known as carbon(iv)oxide fixation which is the reduction of carbon(iv)oxideby hydrogen ions using adenosine triphosphate energy to form a simple carbohydrate.
This simple carbohydrate is changed to glucose for use in the plant or to starch for storage