How Photosynthesis Works

Photosynthesis is the process in which autotrophs convert light energy from the sun into chemical energy in the form of organic compounds, mainly carbohydrates.

Most all autotrophs use the process of photosynthesis. Since photosynthesis involves a complex series of chemical reactions, where the product of one reaction is consumed in the next reaction, it is referred to as a biological pathway. There are two main cycles in photosynthesis, the light cycle, and the dark or Calvin cycle.

The light cycle requires light to work. The light cycle takes place in the chloroplast of a plant cell, more specifically in the thylakoids. The chlorophylls of the thylakoid are what absorb and trap the light energy. Before the light cycle starts, the cell must take in sunlight, water, and carbon dioxide. Once the water is inside the cell the atoms spit and the oxygen atom leaves the cell. The released oxygen atom then forms with another oxygen atom to form and oxygen molecule. The equation of photosynthesis is this: 6CO2 + 6H2O Light energy C6H12O6 + 6O2. After the cell releases the oxygen the light travels through the thylakoid membrane and is converted to chemical energy, which is temporarily stored in ATP and NADPH.

The dark reaction is a series of enzyme assisted chemical reactions to form a 3-carbon sugar. Two of the three carbon sugars combine to from glucose, a very important think in cellular respiration. Overall the dark cycle is when carbon dioxide and the chemical energy stored in ATP and NADPH are used to form organic compounds. Though glucose is not a direct product of photosynthesis it is formed for cellular respiration.

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