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Molecular biology is “fast and crowded” 

 •  • by Paul Ingraham
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Weekly nuggets of pain science news and insight, usually 100-300 words, with the occasional longer post. The blog is the “director’s commentary” on the core content of a library of major articles and books about common painful problems and popular treatments. See the blog archives or updates for the whole site.

I just found this terrific little read about just how crowded and fast cellular biochemistry is, which tends to be de-emphasized by the kinds of schematic illustrations and animations we usually see of proteins and organelles. Some points that stood out:

  • cells aren’t just “crowded,” they are packed, a microscopic mosh pit
  • “instead of thinking of membranes with proteins floating in them like icebergs, we should think of membranes as packed with proteins like a cobblestone pavement”
  • molecules in cells move 30-500 kilometres per hour, and that’s not a scaled velocity; at metre (human) scale, they’d be ripping along at millions of kph
  • the relatively lumbering pace of the “walking” molecules is still super fast, more like sprinting at dozens or hundreds of steps per second
  • the speed and density is what allows for useful random chemical interactions, about a half million collisions per second for any one molecule: “they are covering so much ground in the cell so fast that they will be in the ‘right place’ very frequently just by chance”