CARBON DIOXIDE AND ORGANISMS

633 WD

Carbon dioxide is both a vital requirement for producers – the first organisms in any food chain, and at times a dangerous waste product. Where plants use carbon dioxide during the Calvin cycle of photosynthesis, at night they also produce small quantities due to respiration. Fundamentally, carbon dioxide reacts with ribulose bisphosphate to produce glycerate 3-phosphate in the light independent reaction. In turn glycerate3-phosphate is reduced to triose phosphate using reduced NADP and ATP from the light dependent reaction. This follows through to produce products such as starch, and regenerate RuBP. Without this process, plants cannot produce the organic molecules which are a critical starting point for all food chains and webs. One way that carbon dioxide is released is through respiration. During the Krebs cycle carbon dioxide is removed when turning citrate into oxaloacetate,