Photosythesis The Green machine

Photosynthesis is when plants, and some organisms use the light from the sun to make energy. Normally its only autotrophs, or an organisms that make energy from the sun. The definition of energy is to be able to do work.

Photosynthesis begins with light being absorbed by a plant. The plant can absorb light because of the pigments inside of it. Theses pigments are called chlorophyll a and b there are some others but they aren't important right now. Pigment is whats in your skin that gives you a tan.

So to start to make energy there is going to be a lot of things happening at the same time. First of you have a water molecule or H2O. The water molecule gets split into one oxygen and two hydrogen and an electron. This electron then goes into the electron transport. Think of it as a highway.

Chloroplast is what makes the leaves of a plant look green because that is the only light that they don't absorb. There is anywhere from ten to a hundred chloroplasts in a single cell at any given time.

Okay so all of the stuff that is going to happen right now is going to take place in the chloroplast. The electron that separated from the water molecule then goes into photo system 2. Then the sunlight basically makes it super excited, or gives it more energy than it already had. Its like giving a two year old an entire bag of fun dip. The light then goes for a joy ride through the membrane and takes a stop at photo system 1 and recharges there.

It takes a little energy to make a little energy.

After the electron recharges in photo system 1 it then goes a little farther until it exits from the the chloroplast and goes to make NADPH with a hydrogen molecule.

So the Hydrogen protons that are still inside the chloroplast is starting to accumulate and this process is called Chemiosmosis. Its kind of like diffusion where something goes from a high concentration to a lower concentration. Any way sometimes a hydrogen proton moves across the membrane through a ATP synthase which is an enzyme that takes ADP and the hydrogen proton and makes ATP or energy.

So you have ATP and NADPH, but these are rather unstable for storing energy for a long period of time, so we have only gotten through half of photosynthesis. The next part that is going to happen is called the Calvin cycle. The end result of photosynthesis is to get sugars, or the starting part of sugar at least.

The Calvin cycle has to go 'around' six times to actually get anything out of it. So to start you have to have 1 ribulose and 5 biosphosphates that you add a CO2 molecule to. This is the part where the CO2 is used and the 'waste' is oxygen. This is called carbon fixation, where it then splits into 2 3PGA molecules. You then have 2 ATP molecules come and use their energy and turn into 2 ADP molecules that can go back to the first phase of photosynthesis and get turned back into ATP. You also have two molecules of NADPH that had energy in it too and it then turns into NADP+ and goes baack to the first phase of photosynthesis with the ADP molecules.

This happens twice before the second step of the Calvin cycle where you get 2 G3P molecules. Theses then go into the the third step where you lose a molecule of G3P that later gets transformed into sugar and such. The remaining G3P molecule then meets an enzyme called Rubisco and turns into rubulose and phosphate. Another 2 molecules of ATP get turned into ADP and go back to the the first phase of photosynthesis. After the ATP uses its energy the ribulose and the phosphate molecules get turned into ribulose and biphosphates. These then go back to the starting part of the Calvin Cycle and it starts all over again, and again, and again.

The End.


Created with images by Josch13 - "fern plant green" • Skitterphoto - "forest sun shadow" • phrawr - "Leaves" • deejayres - "Green!" • momentcaptured1 - "plant" • ariesa66 - "fern green plant"

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