Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose or other sugars. This process involves the fixation of carbon dioxide CO2 from the atmosphere, which is then used to produce organic molecules that serve as the building blocks for the organism's growth and energy needs.The process of photosynthesis can be divided into two main stages: the light-dependent reactions and the light-independent reactions also known as the Calvin cycle . The fixation of carbon dioxide occurs during the Calvin cycle.In the Calvin cycle, CO2 is incorporated into an organic molecule through a process called carbon fixation. The enzyme responsible for this process is ribulose-1,5-bisphosphate carboxylase/oxygenase, commonly known as rubisco. Rubisco is the most abundant enzyme on Earth and plays a crucial role in the global carbon cycle.Here's a brief overview of the carbon fixation process involving rubisco:1. Rubisco catalyzes the reaction between CO2 and ribulose-1,5-bisphosphate RuBP , a 5-carbon sugar. This reaction results in the formation of an unstable 6-carbon intermediate.2. The unstable 6-carbon intermediate quickly breaks down into two molecules of 3-phosphoglycerate 3-PGA , a 3-carbon compound.3. The 3-PGA molecules are then converted into glyceraldehyde-3-phosphate G3P through a series of enzyme-catalyzed reactions, which involve the consumption of ATP and NADPH both produced during the light-dependent reactions of photosynthesis .4. Some G3P molecules are used to synthesize glucose and other sugars, which can be used for energy or as building blocks for the synthesis of other biomolecules.5. The remaining G3P molecules are used to regenerate RuBP, allowing the Calvin cycle to continue and fix more CO2.The significance of rubisco in the process of photosynthesis lies in its ability to catalyze the fixation of CO2, which is the first step in converting inorganic carbon into organic compounds that can be utilized by the organism. This process is essential for the growth and survival of photosynthetic organisms and plays a critical role in the global carbon cycle, as it helps to remove CO2 from the atmosphere and convert it into organic matter.