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Introduction The process of photosynthesis is vital to humans and all other living organisms on earth. Through photosynthesis plants use water, carbon dioxide, and light to supply themselves with food and the rest of the world with oxygen. Although all plants carry out photosynthesis, the process by which they do so varies depending on the plant. The rate at which plants produce oxygen is also dependent on the plant. Two classifications of plants that differ in the way they carry out photosynthesis are C3 plants and C4 plants. C3 plants such as soybeans and rice go through two stages of photosynthesis which are light reactions and the Calvin cycle. While in the light, during the Calvin cycle, C3 plants often go through a process called photorespiration when the plant uses O2 for the Calvin cycle instead of CO2 and therefore does not produce food or ATP. This occurs when the weather gets too hot and dry for the stomata to be open and rubisco, the Calvin cycle enzyme for C3 plants, accepts O2 and it overtakes the CO2 concentration . C4 plants such as sugarcane and corn, on the other hand, have adapted to hot, dry climate so that they do not carry out photorespiration. The reason C4 plants differ from C3 plants is because the enzyme used in their Calvin cycle called PEP carboxylase has a high affinity for CO2 and is able to fix the CO2 concentration and not allow oxygen to overtake it.
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