What is it when excited electrons are passed along the electron transport chain?

Answer 1

Energy in sunlight transformed to chemical energy

Process of PhotosynthesisThere are two processes of photosynthesis that a plant utilizes to obtain energy from light. One is the Light Dependent Reaction and the other is the Light Independent Reaction. The equation that can be used to summarize the reaction is

6CO2+6H2O C6H12O6+6O2.

The first process, the Light Dependent Reaction involves light entering the thylakoid membrane. The Thylakoid Membrane, which is contained inside the Chloroplast, contains the pigments needed to absorb light. Inside the membrane the water splitting enzyme splits H2O into O2 and a Hydrogen ion (H+, e-). When the light strikes the pigments (Chlorophyll, Arytenoids, Phycobilins) inside the thylakoid, the electrons from the Hydrogen ion become excited. These electrons are then carried by the Electron Transport Chain to activate the Carrier Proteins. These Carrier Proteins transport Hydrogen molecules to the Stroma. From here the Hydrogen molecules are used in two different ways, the formation of ATP and NADPH. The first way, the formation of ATP occurs as the result of the Hydrogen ions becoming hypertonic inside the thylakoid, these ions are diffused out through the thylakoid membrane. After diffusion these Hydrogen ions combine with ADP and a phosphate group to produce ATP. The second way, the formation of NADPH, occurs as the molecule NADP binds with a Hydrogen ion to produce NADPH.

The second process, the Light Independent Reaction (The Calvin Cycle) occurs outside of the Thylakoid in the Stroma as 3 CO2molecules splits into 6 3-Carbon based Compounds. These 3-Carbon molecules, with the assistance of 6ATP and 6NADPH are then converted into 6 3-Carbon sugars. Because the ATP and the NADPH expended all of their accumulated energy, they are converted back into 6ADP and 6NADP, respectively. From here one 3-Carbon sugar such as C6H12O6 is released for the organism to use as energy. The remaining 5 3-Carbon sugars are used to rebuild the original 5- Carbon compound that began the cycle. Three of these cycles are needed to produce a polysaccharide such as Glucose.