Mitochondria are a badly kept secret. ...There are usually hudreds or thousands of them in a single cell, where they use oxygen to burn up food. ...[… - Nick Lane

Now it's possible to have some kind of protocell with some form of metabolism without any genetic heredity. It's possible in principle. Is it alive?

Life as we know it has both, and the people who say s first are in effect saying, "Well, there's plenty of s, there's plenty of RNA. The environment's providing it for free," without worrying themselves too much about what kind of an environment is going to provide all of that for free, and by definition, an environment which is effectively metabolically sophisticated enough to provide s is non-living and therefore not part of the question, so they're just pushing it aside. I would say that the whole metabolic side is needed to give rise to genetic information and nucleotides in an RNA world in the first place, that it would be a dirty RNA world contaminated with s and s, and s and things...

We all share this basic machinery in cells, and it's not related to whether you're photosynthetic or whether you're phagocytes or whether you are a fungus or whether you're an animal cell. We all share the same machinery. Why? The possibility is that it's not about adaptation to the external world, it's about adaptation to these s. These pesky bacteria that went on to become a mitochondria. Maybe this conflict of interest... [that] had to be resolved somehow was what was driving a lot the elaboration of cellular machinery. It's a kind of local... intimate conflict.