Photosynthesis

Photosynthesis
By Mackensie Nelson and Hunter Karl

Tuesday 14 May 2013

Breakdown the process of photosynthesis into its two stages


1. In the light-dependent reactions, there are two photosystems. In Photosystem 2, H20 splits into H+ and O2. Since there are two hydrogen and only one oxygen molecule, it is written out as 1/2 O2. The splitting of water creates electrons. Sunlight hits the electrons and they become excited, so they travel upwards to the primary electron receptor and bounce down the electron transport chain until they reach Photosystem 1. Energy from the traveling electrons travel through the ATP synthase along with H+, which makes phosphate. Outside, ADP is made into ATP by adding that phosphate. Meanwhile, light hits the electrons and they become re-energized, traveling back up to a second primary electron receptor and going down the electron transport chain until it travels outside. There, two electrons make NADP+ and H+ into NADPH. The ATP and NADPH travel onto the Calvin Cycle.

2. In the light-independent reactions, 3 CO2 enters the cycle and latches onto 3 5-carbon. This is unstable, therefore each one breaks into 2 3-carbons. Traveling onward, ATP gives up a phosphate to one, so a set looks like ATP is now ADP. Then, NADPH oxidizes them. NADPH is now NADP+. There are now 6 G3P molecules. 1 breaks off and while the five move on. This is so that when another round occurs, the 2 3-carbons can form a sugar. As for the other five, 3 ATP give up a phosphate while the hydrogen drops, so now there are 3 ADP.  The cycle begins all over again.

 
 

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