Photosynthesis occurs primarily in the chloroplasts of plant cells. Chloroplasts contain chlorophyll, the green pigment that captures light energy from the sun. Through the process of photosynthesis, plants convert carbon dioxide (CO2) from the atmosphere and water (H2O) from the soil into glucose (C6H12O6) and oxygen (O2) using sunlight.
The overall chemical equation for photosynthesis can be summarized as:
\[ 6CO_2 + 6H_2O + light \ energy \rightarrow C_6H_{12}O_6 + 6O_2 \]
Photosynthesis can be divided into two main stages:
-
Light-dependent reactions: These occur in the thylakoid membranes of the chloroplasts, where light energy is converted into chemical energy in the form of ATP and NADPH. Water is split, releasing oxygen as a byproduct.
-
Calvin cycle (light-independent reactions): This takes place in the stroma of the chloroplasts, where ATP and NADPH produced in the light-dependent reactions are used to convert carbon dioxide into glucose.
Overall, photosynthesis is essential for life on Earth, as it provides the oxygen we breathe and is the foundation of the food chain.