๐ŸŒป Light-dependent Reaction

As in the overview of photosynthesis, the light-dependent reactions utilise light energy to convert it into more usable chemical energy.

So naturally, it starts with light. This is the brief sequence of events:


1. The electrons present in the chlorophyll of the plantโ€™s chloroplasts are brought to a higher energy level (they enjoy dancing more) by light energy. This takes place on the thylakoid membrane, and more specifically in a conglomerate of proteins/enzymes dedicated to this reaction, called photosystem II.


2. To maintain a fresh supply of dancing electrons, light also splits (photolysis) the H2O intoโ€ฆ electrons, protons andโ€ฆ wait for it. Wait for it. Waitโ€ฆ Oxygen! So thatโ€™s how the oxygen by-product is made.



3. Whatโ€™s the deal with the dancing electrons? Theyโ€™re picked up by electron carriers (nightclub bouncers) and thrown out, one by one. This releases energy every time a poor electron is pushed down another flight of stairs (thylakoids are multi-story clubs thank you very much) all the way to…

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