Notes on Photosynthesis and Light-Independent Reactions

Photosynthesis Overview

Light-Independent Reactions (Calvin Cycle)

• The light-independent reactions, also known as the Calvin Cycle, primarily occur in the stroma of chloroplasts.
• These reactions do not directly require light, hence the term 'light-independent.'
• Key reactants include ATP and NADPH produced during the light-dependent reactions.

Key Components and Interactions

• ATP (Adenosine Triphosphate): Serves as an energy source.
• NADPH (Nicotinamide Adenine Dinucleotide Phosphate): Acts as a reducing agent, providing electrons.
• ADP (Adenosine Diphosphate): The product formed when ATP loses one phosphate group during energy release.
• NADP+ (Nicotinamide Adenine Dinucleotide Phosphate - oxidized form): The form that accepts electrons and protons to become NADPH.

Overall Process

• The light-independent reactions utilize ATP and NADPH to convert carbon dioxide into glucose through a series of enzymatic steps.
• The involvement of carbon fixation, where CO2 is incorporated into organic molecules, is crucial in this cycle.

By-Products

• Important by-products of these reactions include glucose and ADP, which can be recycled back into the light-dependent reactions.