How Photosynthesis Works in Plants
Before understanding how photosynthesis works in plants, we should know what it is first. Photosynthesis is a biological process which plays an important role in plants and the earth. Green plants use photosynthesis to create energy from carbon dioxide and sunlight. The energy in the form of glucose is used by the plants to grow and fuel the necessary reproductive activities of the plants. Also, the byproduct of the process of photosynthesis is oxygen, which is released into the atmosphere in exchange for the carbon dioxide used during the chemical reaction of photosynthesis. That is the reason why earth's atmosphere and seas contain oxygen. To simply describe, there are two main stages of photosynthesis: the light reactions and the dark reactions. These two reactions are not just work separately, they are chain reactions, that means light reactions should happen before dark reactions. Therefore, photosynthesis is a continuous process, it is a cycle which following the order from light reactions to dark reactions.
The overview of photosynthesis
Let’s talk about the light reactions. According to the name, it’s obvious that these reactions must take place in the light and in chloroplasts of plants. The source of light reactions are light energy and water, and the light energy is typically provided from the sun but is also effective when it is provided artificially. In this stage, after chloroplasts absorb the light energy, the plants will conduct series of chemical reactions. After these reactions, light energy will be transformed into another type of energy which is the source of dark reactions, and the water will be decomposed into oxygen and hydrogen.
Separate reactions in photosynthesis
After light reactions, the next stage is called dark reactions. Different from light reactions, dark reactions can take place in the light and also without the light. And as I mentioned in last paragraph, the source of dark reactions is partly from light reactions, so that’s why there should be light reactions in the beginning of photosynthesis. During this final stage of photosynthesis, carbon dioxide on the earth can be converted into glucose which is the energy that plants need. The chemical changes in dark reactions require the energy provided from light reactions. And the final product of dark reactions is glucose, which is the ultimate goal for plants to have photosynthesis.
To sum up, photosynthesis can be divided into two continuous parts, light reactions and dark reactions. In the light reactions, the sunlight and water are transformed into the energy that dark reactions need and the oxygen. Then, in the dark reactions, carbon dioxide is converted into glucose which is the energy that plants need. Therefore, the sources of photosynthesis are sunlight, water and carbon dioxide, and the output of it is glucose and oxygen. Photosynthesis, in addition to making food for plants to survive, photosynthesis is an important part of the life cycle of all living things because most of life requires oxygen to survive. Oxygen supply is limited in the atmosphere and if there is no way to transform the carbon dioxide emitted by living things back into oxygen, life would be unsustainable in the long term. Thus, photosynthesis is important not only for plants but also for this earth and all the living things.
Reference
Picture of the overview of photosynthesis retrieved from https://www.abcteach.com/documents/clip-art-photosynthesis-color-i-abcteachcom-32745
Picture of Separate reactions in photosynthesis retrieved from
http://www.old-ib.bioninja.com.au/higher-level/topic-8-cell-respiration/82-photosynthesis.html