Photosynthesis

This week in AP Biology we discussed about photosynthesis. Photosynthesis is the process where plants use sunlight to synthesis their food from carbon dioxide and water. I have been taught photosynthesis since elementary, but I never knew how complicated and complex it really was until we started learning about it in depth. Photosynthesis occurs in the chloroplast of the plant.There are two parts to photosynthesis, and they are the light reaction and the Calvin Cycle (also known as the dark reaction) . The light reaction occurs in the thylakoid membrane and it converts light energy to make chemical energy. The light that is absorbed is used to make ATP and also produces NADPH. The Calvin Cycle uses ATP as an energy source and also consumes NADPH so it can add high energy electrons to make glucose (sugar). There are three phases in the Calving Cycle. The first phase is called Carbon Fixation which is when carbon dioxide is made into a five carbon sugar called ribulose biphosphate or RuBP. The second phase is Reduction which is when ATP and NADPH are used to convert 3 phosphoglycerate to glyceraldehyde 3 phosphate which is the predecessor to glucose and other sugars. And finally the third phase is Regeneration. Regeneration is when even more ATP is used to convert glyceraldehyde 3 phosphate back to RuBP (which is the acceptor for carbon dioxide) so the cycle is complete. For the Calvin Cycle to continue this, the light reaction must continue regenerating ATP and NADPH. Without photosynthesis, anything that needs oxygen to survive will not be alive without it. Photosynthesis is one of the most important processes to occur.