Question

When and where does photosynthesis occur?

Answer 1

Photosynthesis occurs in green parts of the plant only in presence of light.

Explanation:

Photosynthesis is a photo-chemical process in which simple substances like `CO2 and H2O` are converted into `C6H12O6 and O2`.

Light is entrapped by chlorophyll pigment that is present in chloroplast. Photosynthesis occurs in 2 main steps:
1 Light reaction or Hill's reaction and
2. Dark reaction or Blackmann's reaction.

Light reaction occurs in light, in which solar energy entrapped by chlorophyll is converted into chemical energy in the form of ATP molecules. Photolysis occurs in which `H2O` is broken down to liberate `O2` and reducing power `NADPH2` is produced.

Dark reaction occurs independent of light, but is dependent upon the end products of light reaction , i.e. `ATPs and NADPH2`.

Dark reaction occurs in a series of enzymatic reactions and results in the conversion of `CO2` into `C6H12 O6` utilizing `ATPs and NADPH2` .

The series of reactions occurring in dark reaction constitute Calvin's cycle.