Light and Dark reactions ( Calvin cycle / C3 Cycle) are sequential reactions which occur during Photosynthesis process.
In this post we will look into some important differences between these two vital aspects which are essential for synthesis of food in Plants and some other organisms.
| Difference | Light Reaction | Dark or Calvin Cycle |
| Place of occurrence | Thylakoid membrane of chloroplast | Stroma of Chloroplast |
| Requirement of Light | Sunlight is essential | Do Not require sunlight, but takes place mostly during the day. |
| Type | Photochemical | Biochemical |
| Process | Pigments absorbs of light energy from sun and converts into chemical energy | Involves fixation of CO2 to form Glucose. |
| ATP and NADPH | Produced | Utilized (That was produced during light phase) |
| Oxygen | Released | Not liberated |
| Order | First phase of photosynthesis | Second phase ( follows light reactions) |
| Water – (Photolysis) | split into Hydrogen ions and Oxygen | No splitting of water observed |
| End products | ATP, NADPH and Oxygen | Glucose |
Part I of Photosynthesis : Introduction
Image Credit – Openstax biology.