The process of photosynthesis is divided into two main parts. The first part is called the light dependent reaction. This reaction happens when the light energy is captured and pushed into a chemical called ATP. The second part of the process happens when the ATP is used to make glucose (the Calvin Cycle).Click to see full answer. Likewise, what is the first step of photosynthesis?The first stage of photosynthesis is the light dependent reactions. Read More...