Photosynthesis | How plants make food for everyone !!!
When chlorophyll absorbs light energy, it becomes photoexcited , meaning that its electrons are elevated to a higher energy state. These excited electrons are then transferred through the electron transport chain (ETC) , which ultimately helps produce ATP and NADPH —key molecules used in the Calvin cycle (the light-independent reactions). Why must the photoexcited electrons be replaced with electrons from water molecules? Electron Loss in Chlorophyll : When a chlorophyll molecule absorbs light, it excites an electron to a higher energy level. This electron is then lost from the chlorophyll molecule and must be replaced to prevent the chlorophyll from becoming oxidized (i.e., it must remain in its reduced state for the process to continue). Water Splitting (Photolysis) : In order to replace the lost electrons, the plant splits water molecules through a process called photolysis . Water (H₂O) is broken down into oxygen (O₂) , protons (H⁺) , and electrons (e⁻) : 2 H 2 O → 4 H + + 4 e...
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