What role does sunlight play in the light-dependent reaction as it regards electron transport

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I am a high school student taking AP Bio, and this part of photosynthesis confuses me. I’d appreciate a sort of detailed explanation

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Anonymous 0 Comments

TL;DR: shining a light(=photon=energy) on an atom forces the electron to jump up a shell, thus making it more unstable and therefore reactive

Allright, so this is the explanation to my understanding:

Most of us know about Bohrs atomic model with the electrons only existing in specific orbits/shells around the nucleus of the atom, right? These orbits are actually just representations of energy levels (also Bohrs words).

But we also know that these electrons are moving spontaneously, and everything moving must consume energy, right? Therefore the atom needs a way to regulate energy within itself in order not to collapse, and it does this by changing orbits/energy levels. The higher the orbit, the more energy in the electron. Here it’s important to note, that light is practically just a clump of photons, which contain energy.
When an atom is hit by a photon, with a very specific amount of energy, it absorbs this energy and jumps from e.g. the first shell to the second shell. We call this absorption. The opposite happens when the electron throws a photon out and jumps from e.g. the second to the third shell. Thats called emission.

So thats great and all, but a little more physics than expected, right? Try to remember, that each electron and atom wants to be as stable as possible. How do we do this? Have a low level of energy! Thats why they looove being in the inner shell. When you shine light upon these plants (or substitutionreactions in orgo, for that matter) it excites the electrons within the molecules of the plants, making them even more reactive.

Though i must admit, I don’t know if this is applicable for the plants. I must assume it is

Anonymous 0 Comments

Photosynthesis and the burning of glucose in the mitochondria rely on the same principle, roughly. It’s that if you separate a proton from water, this proton wants to reunite at some point. You use this driving force to generate high energy molecules such as ATP or reducing agents like NADH in mitochondria. The second driving force is that carbon of glucose oxidizes to carbon dioxide spontaneously. The mitochondria do this in a controlled way by pulling electrons from Carbon-Oxigen bonds one by one, by pulling them onto metals that are kept in a flat cage. These metals are then handing over the electrons to a neighbor, but this handover only happens if a proton is pulled from a nearby water (not in every step, and it’s not that easy as discribed). But while the glucose to carbon dioxide reactions drive that passing on. Sunlight does the opposite way. Sunlight excites these metals, and from it electrons are pulled off to reduce carbon. These electrons are refilled by pulling apart water and form oxygen