Chlorophyll synthesis is the chemical reaction by which gas and water become matter.
The quintessential “green” process: decarbonization and oxygen production using a few molecules of (pure) water and a little sunlight.
It all happens inside tiny organelles called chloroplasts, found in plant cells (and something similar exists in some bacteria). Biochemistry tells us that chlorophylls are sensitive to different light energies to best harness the sun’s energy, from dawn to dusk. Botany reminds us that leaves change color throughout their lives, going from an initial pale green to a more intense green and then to red in an inexorable decay of their chlorophyll content. Biology tells us that without pure water and sunlight, it will be impossible to produce oxygen.
Like all magical things, photosynthesis pulsates. It has two cycles: the light phase and the dark phase. Each is indispensable to the other … producing sugars and molecules of pure energy.
It is green because it absorbs blue and red light; To our eyes, it appears to be a reflective color, namely green. But special, non-human eyes see and measure it as a different color: red.
The magic of this color change in chlorophyll (from green to red) occurs because it develops an intense fluorescence. A leaf illuminated by ultraviolet light appears red
The curious phenomenon is due to the shape of this molecule: a long string of carbon atoms and a ring at the end with a magnesium atom at the center. The ring is a porphyrin heterocycle similar to that of hemoglobin in red blood cells, but with an iron atom instead of magnesium. It is precisely this ring that absorbs ultraviolet light and emits red light in the form of fluorescence.
A green molecule that absorbs blue and red, but appears red when illuminated in blue.