Mathematical language is the translation for human understanding of reality itself. It is through complex equations that we have come to understand situations as intricate as relativity itself. But not only physics or quantum mechanics have mathematical expressions that are the full essence of their science, biology itself also has a very important equation with which life itself could be described.
Energy, carbon and electrons
Every being needs three factors that will provide it with life: a source of energy, a source of carbon and a source of electrons. In that sense, photosynthesis is the clearest example that encompasses how the sum of abiotic factors through a series of processes makes life possible. And although photosynthesis is not particularly efficient from an energy point of view, it is the definitive form of self-sufficiency. Furthermore, the first organisms capable of oxygenic photosynthesis were the first to produce carbohydrates and oxygen from carbon dioxide. Thanks to them, the first Great Oxidation Event occurred that later made complex life possible.
In that sense, the most important equation in biology is CO 2 + H 2 O → C 6 H 12 O 6 + O 2. (Its balanced version is: 6CO 2 + 6H 2 O → C 6 H 12 O 6 + 6O 2). Whose translation would be: carbon dioxide + water → glucose + oxygen. And although it is deceptively simple, it describes the process by which plants and organisms obtain their sources of vitality. And how in turn, the result serves as food for complex life, including man. That is, without oxygen in the body, the human being would not have developed. There would probably be other forms of life very different from what we know, or it simply would not exist.
Behind the most important equation in biology
Within this equation that is so important for biology, you can see how water is the source of electrons that plants need to begin the photosynthetic process. When the light (energy) source hits the chlorophyll, this molecule gives up its electrons which will then trigger other amazing reactions. However, the chlorophyll molecule wants to recover its electrons, so it steals them from the water molecule, which ends up separated into two protons (H+) and an oxygen atom. The oxygen atom is now alone and is not happy with it, so it looks for a partner and associates with another oxygen atom, forming O2. The latter is the molecular form of the gas that .
But that is just the beginning of the journey. Returning to the electrons given up by chlorophyll, these pass from one protein to another and as they travel through the plant tissues, they cause the protons to be pumped to the membrane of the photosystem called the thylakoid. With this action, a powerful electrochemical gradient is generated, as if it were a battery. However, just like your cell phone battery, this electrochemical gradient will deplete its energy at some point. At that moment and to counteract it, an energy-rich molecule called ATP is generated.
When the electrons that have been jumping from one protein to another finally finish their journey, they are deposited on a molecule called NADPH. If NADPH were to be described as a human artifact, then it would be an electron catapult. Since it is capable of transporting them to where they are required in order to build something else, through a process that experts know as the Calvin cycle.
Food for almost all forms of life
This cycle is the moment where another extremely important abiotic factor, carbon dioxide, joins the adventure. At this moment the carbon dioxide is transformed into a solid form that will later be combined with a five-carbon sugar. The result will be a six-carbon sugar called G3P, the cornerstone of plant subsistence. Thanks to it, the plant can carry out a variety of processes. From generating its own food, to building structural molecules that help the plant grow.
Most of the life that this planet shares with us depends on photosynthesis. This process feeds its oxygen to the aerobic beings that completely depend on it. Without the development of the process described in the photosynthesis equation we would simply not exist, which is why it is considered the most important expression of biology.