Why is Photosynthesis Important?

"Photosynthesis is an important process which allows organisms to produce food without the intervention of any other organisms. This specialized reaction, occurring only in autotrophs, has several key features that are fundamental for understanding the process as a whole. Factors of where the process takes place, the reactants and products of the reactions, and what happens in the process are all important elements in the success of photosynthesis.

Photosynthesis occurs in the chloroplast, an organelle found only in plant cells. Contained in the chloroplast are multiple structures where different element of photosynthesis take place.

One such structure are thylakoids; flattened membrane sacs that store pigments like chlorophyll. This is where the light-dependent reactions occur. Thylakoids arrange in stacks called grana. Grana are surrounded by stroma, a fluid filling the chloroplast similar to the cytoplasm in cells. In the stroma is where light-independent reactions take place. Through these individual structures, photosynthesis is able to take place.

Photosynthesis is a biochemical reaction, so there are specific reactants and products to enter into and exit from the process each time the cycle takes place. For the reaction to occur, there must be carbon dioxide, CO2, and water, H2O. Produced from this are oxygen, O2, and high energy sugars, C6H12O6. However, for the equation to be balanced with both reactants and products, there must be 6 carbon dioxide reactant molecules and 6 water reactant molecules, or, 6CO2 + 6H2O. There will also be 6 oxygen molecules produced, or 6O2. This equation written in full looks like carbon dioxide + water + light †’ high energy sugars + oxygen, or in numerical form, 6CO2 + 6H2O + light †’ 62O + C6H12O6+602. Overall, the equation of photosynthesis shows the what enters the reaction and what is produced.

While photosynthesis is often viewed as having a single step, the process actually has two parts; the light-dependent reactions and the light-independent reactions. Each process has its own role in making all of the products of this reaction. The light-dependent reactions, occuring in the thylakoids, need sunlight to take place. They transform water into oxygen and use the energy of sunlight to convert ADP and NADP+ into ATP and NADPH which carry energy. On the other hand, light-independent reactions, also known as the Calvin Cycle, occur in the stroma and do not need sunlight. They use the energy in ATP and NADPH made during the light-dependent reactions to convert carbon dioxide from the environment into high energy sugars. The energy is then turned into ADP and NADP+ which then cycle back to the thylakoids for the next set of light-dependent reactions. It is through both of these processes working simultaneously that plants can continuously make food.

In conclusion, each of the individual elements of photosynthesis, including the location of the process, the ingredients of the reaction, and the parts of the reaction have a key role in this function. Through these many pieces, autotrophs are able to thrive. With an awareness of these elements, one has a better understanding of the process of photosynthesis.

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