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What is the role of NADPH in photosynthesis?
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photosynthesis
Diagram of photosynthesis showing how water, light, and carbon dioxide are absorbed by a plant to produce oxygen, sugars, and more carbon dioxide.
In photosynthesis, NADPH serves as a vital high-energy electron donor and reducing agent. Its role is essential for converting carbon dioxide into carbohydrates.12
The function of NADPH can be broken down into two primary stages:
- Formation: During the light reactions of photosynthesis, specifically within photosystem I, NADP+ accepts electrons and a proton to become NADPH. This process captures energy derived from light absorption.31
- Utilization: NADPH remains in the stroma of the chloroplast, where it is used in the Calvin-Benson cycle. Along with ATP, NADPH provides the necessary energy and reducing equivalents (electrons) to drive the reduction of carbon compounds, ultimately facilitating the production of glyceraldehyde-3-phosphate, a key sugar intermediate.42
Essentially, NADPH acts as a carrier that transports the energy harvested from light to the chemical reactions responsible for carbon fixation.41