In Greek it is where we find the etymological origin of the word that we are now going to analyse in depth. Thus, we come across the fact that photosynthesis is the result of the sum of three defined parts: photo, which is synonymous with “light”; syn, which is equivalent to “with” and thesis, which can be defined as “conclusion or position”.
Although it is a concatenation of enzymatic steps of amazing complexity, photosynthesis can be summarized in a few stages. The fundamental data is the capture of the luminous energy coming from the Sun by means of a series of pigments, of which chlorophyll stands out in particular. Therefore, energy from the Sun in the form of light (light energy) is transformed by the metabolic processes of photosynthesis into chemical energy, stored in organic molecules. Since animals cannot perform photosynthesis, they are forced to consume these molecules directly from the intake of vegetables or other animals that have previously been nourished with vegetables. As final products of the degradation of the organic molecules, carbon dioxide and water, necessary for the restart of the complete cycle, are returned to the environment.
The formula of photosynthesis explains the way in which plants take energy from the sun and use it to convert carbon dioxide and water into molecules necessary for their growth, that is, food. Here, the elements that intervene initially are carbon dioxide and water, which are subsequently converted into glucose and oxygen. This process requires that multiple chemical reactions take place, therefore, it can be expressed in the following chemical formula:
6 CO2 + 6 H2O → C6H12O6 + 6 O2
This transformation takes place due to the incidence of sunlight, which allows the plant to transform carbon dioxide and water into the nutrients it needs (glucose) and oxygen that is released as waste. In turn, the chemical elements that are shown in the formula of photosynthesis enter and leave the cells of the plant through a diffusion process, known as osmosis, which allows the plant to take carbon dioxide from the air and release then oxygen to it.
As well as the air compounds are absorbed and released through the process of osmosis. Sunlight is captured due to the presence of a green chemical called chlorophyll.
Chemical equation of photosynthesis
The chemical equation of photosynthesis can be read as follows:
Carbon Dioxide + Water (+ Sunlight) → Glucose + Oxygen
It is important to note that this transition is only possible due to the incidence of sunlight, which is included within the formula in this way, since it does not constitute a substance per se. On the other hand, the way to formulate this equation chemically, would be by means of the following balance:
6 CO2 + 6 H2O → C6H12O6 + 6 O2
Where CO2 = Carbon Dioxide; H2O = Water; C6H12O6 = Glucose; O2 = Oxygen
Plants need to take numerous chemical elements to stay alive and healthy. The most important are carbon, hydrogen and oxygen. Hydrogen and oxygen are taken from water and soil, on the other hand, carbon and oxygen are taken from the carbon dioxide and oxygen present in the atmosphere. Water and carbon dioxide are used to synthesize food during photosynthesis. Oxygen is necessary to release energy from food during the process of plant respiration.
In addition to these three basic elements that are indicated in the formula of photosynthesis, there are other mineral compounds that all plants require to grow healthy. These are absorbed by the roots as ions dissolved in the water of the soil.
Nitrate is essential for the manufacture of amino acids during the process of photosynthesis. The amino acids, in turn, are what allow proteins to be manufactured.Plants whose leaves turn different colours to green, are probably going through a stage of mineral deficiency and the process of photosynthesis will not be carried successfully.
Cells of the leaves
Plants, like all living beings in the world, need to feed. For this reason, they use the process of photosynthesis to convert chemical compounds such as carbon dioxide and water into the glucose they need for their cells to grow and develop. Similarly, this process of photosynthesis is only viable due to the action of cells located in the leaves of plants, where a substance called chlorophyll allows the sun’s energy to be stored and used to transform chemical compounds taken from the air.
Chlorophyll is rich in chloroplasts and enzymes that allow leaf cells to react during the process of photosynthesis.
Parts of the Cell
The cell is composed of multiple parts that play a fundamental role in the process of photosynthesis. Some of these parts are the following:
- Chloroplasts: they contain the chlorophyll and enzymes necessary for the chemical reaction of photosynthesis to occur
- Nucleus: it contains DNA with the genetic information of the plant that is used by enzymes during the process of photosynthesis
- Cellular Membrane: is the permeable barrier that regulates the passage of gases and water both to enter and to leave the cell
- Vacuola: allows the cell to remain firm
- Cytoplasm: is the place where some of the enzymes and proteins used during the chemical process of photosynthesis are manufactured.
Factors that limit photosynthesis
There are three factors that can limit the chemical reaction of photosynthesis: the intensity of light, the concentration of carbon dioxide and temperature.
Intensity of Light
When there is not enough light, a plant cannot carry out the process of photosynthesis efficiently, it does not matter that there is enough water and carbon dioxide in the environment. Therefore, increasing the intensity of the light will immediately increase the speed of the photosynthesis process.
Concentration of Carbon Dioxide
In some particular cases the process of photosynthesis is restricted due to the amount of concentration of CO2 in the air. Even if there is a lot of sunlight and water, a plant cannot carry out photosynthesis without there being enough carbon dioxide in the air.
Photosynthesis process depends on temperature, if the temperature is low, so the photosynthesis process becomes slow. In the same way, plants cannot carry out photosynthesis when the temperature is very high.