Vox Hunt: Robots in the Sky

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.

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8 thoughts on “Vox Hunt: Robots in the Sky

  1. I am so glad there are people like you out there who understand this stuff, as that allows people like me to go 'yeah-huh' and go on with our dim existence. (That came out more morbid than I intended).

  2. Wow, I really thought that with a blog post about transforming and vision some one would have made some sort of clever "More than meets the eye" comment. But maybe I'm the only one that read this post and immediatley heard 80's cartoon theme songs.

  3. You pick my favorite molecule in the whole wide world! It is a pretty nifty little thing that works so well. And smells a little like roses (or at least that is what I think, but this is a point of heated debate between the retinal users…)

  4. Skins — the problem is that I was a child of the 70s, not the 80s, so that I would have never thought of that tie-in — though it would have been a good one… :)

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