Overview of photosynthesis. What photosynthesis accomplishes, why it's important, and how the light-dependent and light-independent reactions work together. Photosynthesis is usually represented by the equation 6 CO2 + 6 H2O + light --> C6H12O6 + 6 O2. During this process, organisms such as plants go through the light-dependent and light-independent reactions to convert carbon dioxide and water into sugars and oxygen.