That burger you ate today? Those veggies you bought yesterday? It’s all chemistry, baby. It is time to reveal the one and only truth behind food production.
The entire entity of food production, putting all our debates and rivalries aside, comes down to one process: a process called photosynthesis in which light energy from the sun is converted into the chemical energy of sugars.
Let’s start with the sun. Only part of the light the sun is emitting makes it to the surface of our earth, this blue planet floating in space with a distance of roughly 150,000,000 kilometers from the sun. If that distance eludes you, think of it this way: to reach the sun with a commercial jet, you’d have to be prepared to sit on that plane for about 19 years.
Light is, essentially, energy.
In a plant, light is absorbed into the chloroplast. This is the unit where photosynthesis starts, a powerhouse which works day and night. In chloroplasts we find chlorophyll which is the actual molecule absorbing the light.
You should know something about chlorophyll. Do you know why green plants are green? It is because chlorophyll best absorbs light in red and blue wavelengths. It is a poor absorber of the green light spectrum. Hence, when you see a green plant it means this plant does not absorb light from the green range.
Now to the actual photosynthesis part taking place in the chlorophyll: in the presence of light, carbon dioxide and water, a certain chemical reaction takes place. Electrons are transferred from water to carbon dioxide molecules.
Let’s recap that. The water molecule loses electrons. This is called oxidation. The carbon dioxide molecule gains electrons, this is called reduction. When the carbon dioxide molecule receives extra electrons, energy rich sugar molecules are formed in the chloroplast.
Photosynthesis happens in two main parts, in light dependent reactions and the light independent reactions. The first one takes place when light energy has been captured and pushed in the plant into a chemical called ATP. The second one takes place when ATP is used to make glucose, also known as the Calvin cycle.
The end result of these reactions are glucose and oxygen. Oxygen is merely a bi-product, released into the atmosphere and making it possible for you and me to exist. The sugar, glucose, is consumed by the plant or the animal, human being or any organism eating it.
What’s the broad level conclusion to be drawn here?
We can produce synthetic meat, we can eat insects, we can build skyscrapers with vertical gardens. But so far we have no alternative for photosynthesis. (To be fair, scientists are working on artificial photosynthesis and last summer ‘the world’s first man-made leaf’ was introduced. It is not available for grand scale commercial use, though.)
Virtually every food item we grow, consume or throw away is dependent on photosynthesis. The calories we eat are energy once derived from the sun.
Photosynthesis is an ecosystem service which every creature in the world can be grateful for, the very basic reason for our existence, the ultimate reason to appreciate nature.