Answer:
I feel it's to easily differentiate the positive from the negative...... like in gram staining of bacteria, the colour tell us which bacteria is gram positive or gram negative...... I just feel that this is science and it is advisable to know what the opposite result of an experiment should look like.
The Light Reactions of Photosynthesis. Light is absorbed and the energy is used to drive electrons from water to generate NADPH and to drive protons across a membrane. These protons return through ATP synthase to make ATP.
<u>What is the end product of light reaction in photosynthesis?</u>
The energy from sunlight is converted into a small amount of ATP and an energy carrier called NADPH. Together with carbon dioxide, these are used to make glucose (sugar) through a process called the Calvin Cycle. This is the things happening during light reaction of photosynthesis .
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In the light dependent reactions light energy is absorbed by the photosytem II and an electron is released. This electron causes a process called photolysis to occur(H20-->2H++2e-+1/2O2). This is how O2 is released in the atmosphere. The electrons resulted from photolyisis enter the electron transport chain. In the electron transport chain using the energy in the elecrtons, hydrogen protons are pumped inside the thylakoid. Those protons accumulate to form an electrochemical gradient. That means the protons need to flow out, and they do through an enzyme called ATP-synthase which turns ADP and inorganic phosphate into ATP and water. In the electron transport chain, the electrons reach Photosystem I where NADP+ is reduced and becomes NADPH.
ATP and NADPH store the energy absorbed in the light dependent reactions. Those two molecules are needed when CO2 is fixated in Calvin's cycle to synthesize glucose.