Molecular biology is “fast and crowded” ∞
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”