Life pays universe a ‘heat tax’ to run precise chemical reactions Premium

A study reveals that cells produce excess heat as a 'tax' for maintaining chemical reactions far from equilibrium for efficiency.

Living things dump a lot of heat into their surroundings.

The universe is strict about conserving energy. If there’s a soup of cells and you make them settle down and work together in orderly fashion, you reduce the system’s entropy. In return you need to pay a ‘tax’ to the universe, to account for the drop in entropy. Scientists have interpreted the heat dumped by living things to be this tax.

There’s a problem, however: it’s two orders of magnitude higher than it needs to be to account for the entropy. What could the rest of the heat be about?

A new study by University of Freiburg, STFC Daresbury Laboratory, and University of Edinburgh researchers has argued that life produces so much heat because of how cells optimise their chemistry.

Cells have thousands of chemical reactions happening all the time. To work well, these reaction networks need to be precise and robust without trading off speed. When cells build proteins, they need to avoid making mistakes like putting the wrong amino acid in the chain. When cells build structures like their ‘skeleton’, they need to make parts of very particular sizes. And when they respond to stress, like sudden heat, they need to react quickly.

The researchers have proposed that cells achieve all these different goals using the same chemical setup, so to speak, i.e. they create chemical cycles that are driven far from equilibrium — like pushing a merry-go-round really hard instead of letting it just slow down once molecules have had their turns on it.