What is Light Reaction, and Dark Reaction?

Light reaction- It is the initial stage of photosynthesis, in which series of biochemical reactions takes place that requires light energy which is captured by light-absorbing pigments 'chlorophyll' to convert into chemical energy in the form of ATP and NADPH (supplement).

These reactions take place on the thylakoid membranes of the chloroplast.

Dark reaction- It is the second step of photosynthesis, also known as a carbon-fixing reaction. It is a light-independent process in which sugar molecules are formed from the carbon dioxide and water molecules and also utilizes the energy from ATP and NADPH to produce glucose.

These reactions take place in the stroma of the chloroplast.