Universal ancestor of all life on Earth was only half alive

Interestingly, I only learned about proton gradients and the relation to the vents a few days ago - in the documentary series "Wonders of Life" [1]. As a non-biologist, I've been enjoying the show a lot. It's on Netflix (at least in the UK).

[1] https://en.wikipedia.org/wiki/Wonders_of_Life_%28TV_series%2...