[T]he '' contends that ageing and many of... [its associated] diseases... are caused by... free radicals leaking from mitochondria during normal . ...As they burn up food using oxygen, the free-radical sparks escape to damage adjacent structures ...Many cruel inherited conditions... are linked with mutations caused by free radicals attacking mitochondrial genes.

I like philosophers. I think they can teach scientists how to think very often, and... there's a lot of sloppy thinking among scientists, and I think philosophers can be quite rigorous about it. It gets a lot of scientists cross with philosophers who don't engage with science, but I think there are more philosophers these days who are engaging in a serious way with science. I think they have important things to say.

[Life is] a continuum. I think there are some phase transitions, probably, and the origin of... genetic information is probably one of them. ...[W]e are doing some modeling work to try and work out how evolvable... a geological system [can] be along the path to getting to cell-like things that... most people would understand as life. How far can you go down that line before you have genetic inheritance? ...[A] long way, but you get to a point where... it's no longer evolvable. ...[I]n our modeling, you can get to a point where you're capable of producing s capable of making copies of themselves with a degree of sophistication, but getting beyond that, to specializing to different niches and so on, I don't see the way, without genetic inheritance.

For decades, biology has been dominated by information—the power of genes. ...[Y]et there is no difference in the information content of a living protozoon and one that died ...The difference between alive and dead lies in energy flow ...the ability of cells to continually regenerate themselves from simpler building blocks.

What is [life] it? Would we even recognize it. What I imagine we would find would be cell-like things. Not a million miles away from bacteria, using , probably in water, not because it's the only way of organizing. It's just that carbon is very good at that kind of chemistry. It's very common in the universe. Water is ubiquitous. We know, from the principles of life on earth, that all this stuff works and we know that it's thermodynamically favored. ...[J]ust statistically, I would expect, maybe 900 times out of a thousand that life would be organized in a similar way to life here. That's not to say it can't be different. It's just probably... going to be similar.

From around the mid 1990s, researchers discovered that is... governed... by the mitochondria. ...[T]he failure to commit apoptosis is the root cause of cancer. ...In cancer, individual cells bid for freedom ...Without , the bonds that bind cells in complex s might never have ebvolved.

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It would be a little disappointing if we didn't even find bacteria in our own solar system. I would be rather surprised to find what I would describe as large, morphologically complex life. ...It only arose once on earth. That doesn't necessarily mean that it's improbable... but it does raise some interesting questions about why, and... I think we can apply principles to it, and those principles effectively are why do bacteria and , as assistive groups to the bacteria... They're biochemically very complex. They're genetically very complex. They're kind of structured in a different way where they have large, complex metagenomes, but... I doubt very much that we'll ever find anything of the [morphological] level of complexity of a flea, composed of bacterial cells.

Does anyone care if there's an awful waste of space? It's a form of wishful thinking... We would love for the Universe to be full. ...Personally, I grew up on the Hichiker's Guide to the Universe, those kind of crazy science fiction yarns, or Star Wars or whatever it may be. The idea that the Universe is full of other intelligent beings, all kind of finding a way of getting along or having a war, but having some heroism thrown in, but... it's all human vision of ourselves thrown onto a cosmic scale. Do I believe any of it? No... Is there anything that I think, from my understanding as a biologist, that would tend to lead to that? No... Does it matter if it's a tremendous waste of space? Well, that's to say "What's the point of the Big Bang?" I don't know. The idea that the Universe may be completely empty apart from matter and energy? It would seem to be, perhaps, the default hypothesis. The fact that we find life is surprising. It would be nice if there were laws of the Universe that tended to give rise to life. Maybe there are at the level of bacteria. I don't see it at the level of large, morphologically complex beings... I think it's emotive. It's pleasing, but I doubt it's true.