Show us a transformation.
Wow – how could I not answer this one…
During my whole career, I’ve worked with chemists that make molecule after molecule that have never been made before – it’s pretty amazing and I really appreciate their skill. But, as usual, nature dwarfs what we can do and the most remarkable transformation that I can think of is: the conversion of light energy into vision.
There is a small molecular co-factor called retinal (derived from vitamin-A, so eat your yellow and orange roots and vegetables…) that is chemically attached to a protein called an opsin. These opsins reside in your retina.
In the dark, retinal exists in what is called the cis-form (A). When a photon of light (a single photon of light, mind you) hits the retinal part of the molecule, the energy is absorbed and the converts cis-retinal into its trans-form (B).
Now since the cis-retinal was all snug within the opsin protein, when it is converted from A to B, the opsin part changes its own structure to adapt to that change. This change in opsin structure causes activation of other proteins within the cell, which in turn cause the closing of some ion channels, which depolarize some membranes on neurons, which cause an electrical impulse to be transmitted to the brain, which your brain knows to interpret as vision. Wow.
Note: there are different opsins that are responsible for black-white-grey vision and still others that respond to different wavelengths (colors) but they all use the same retinal conversion at their core.
Oh, and the whole process takes place in less than a microsecond.