Free Photosynthesis and Chloroplasts revision notes for OCR A Level Biology – covering specification point 5.2.1 (b).
Introduction to Photosynthesis
Photosynthesis consists of two distinct stages linked together:
- The light-dependent reactions: Light energy is absorbed and converted into chemical energy in the form of ATP and reduced NADP (NADPH).
- The light-independent reactions: ATP and reduced NADP are used to capture carbon dioxide and attach it to organic molecules (carbon fixation).
The diagram below shows how the light-dependent and light-independent reactions are linked:

Chloroplast Structure and Function
Photosynthesis in eukaryotic organisms occurs within chloroplasts.
The diagram below shows the typical structure of a chloroplast:





