Photosynthesis is the process by which plant organisms are able to create organic matter from inorganic matter and light. This formula is made up of carbon dioxide and sunlight. It is produced in plant cells and generally results in glucose, oxygen, and water.
What is photosynthesis
Photosynthesis is a process in which light energy is captured and transformed into chemical energy. During this conversion, carbon dioxide and water produce glucose and oxygen. Therefore, photosynthesis is the primary source of organic matter for living beings. It is also a source of energy and oxygen production.
In plants, photosynthesis takes place mainly inside the leaves. Carbon dioxide is obtained through tiny pores in plant leaves, called stroma. Oxygen is also released through them. The water is absorbed by the roots and transferred to the leaves of the plant. Sunlight is obtained through chlorophyll , a green pigment found in chloroplasts, the cellular structures of plants.
In nature there are the following types of photosynthesis:
- Oxygenic photosynthesis : is that carried out by plants, algae and cyanobacteria. In this type of photosynthesis, water gives up electrons and oxygen is produced.
- Anoxygenic photosynthesis – In this process, photoautotrophic organisms transform light energy into chemical energy for their growth and do not produce oxygen. Some organisms that produce this type of photosynthesis are: purple and green sulfur bacteria, acidobacteria, and heliobacteria, among others.
The formula of photosynthesis: chemical reaction
Photosynthesis is a chemical reaction in which solar energy is converted into chemical energy that is stored in the form of glucose, releasing oxygen and water. This can be expressed by the chemical formula:
6CO 2 + 12H 2 O + light → C 6 H12O 6 + 6O 2 + 6H 2 O
That is, in this process six molecules of carbon dioxide (6CO 2 ) and twelve molecules of water (12H 2 O) are used. As a result, glucose (C 6 H 12 O 6 ), six oxygen molecules (6O 2 ) and six water molecules (6H 2 O) are produced.
The phases of photosynthesis
The formula of plant photosynthesis can also be explained, in more detail, according to its different stages:
- Light Phase: During this phase, light energy reactions occur mainly in chloroplasts. Light functions as a stimulant for energy production in the form of adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH).
- Dark Phase – In this stage, carbon dioxide is converted to sugar using the ATP and NADPH that was produced earlier. It is a process known as carbon fixation or Calvin cycle. At this point, the light phase already caused the formation of organic matter by means of inorganic substances. Therefore, this phase is photoindependent, that is, it does not require the presence of light, since it can be carried out with or without it.
- Main stages of the Calvin process:
- In carbon fixation, carbon dioxide combines with a five-carbon sugar, creating one of six.
- In the reduction stage , the ATP and NADPH produced in the light reaction stage are used to convert the six-carbon sugar to two molecules of a three-carbon carbohydrate, glyceraldehyde-3-phosphate. Glyceraldehyde-3-phosphate is used to produce glucose and fructose. These two molecules combine to produce sucrose, or sugar.
- In the regeneration stage , some glyceraldehyde-3-phosphate molecules are combined with ATP and converted back to the five-carbon sugar, ribulose-1,5-bisphosphate (RuBP). With the complete cycle, the ribulose-1,5-bisphosphate is available to combine with carbon dioxide so that the cycle can start again.
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