>>10894582The whole carbon being a stable atom that can hold 4 functional groups means that any life will probably use it as the building block (silicon holds it's electrons too closely and doesn't form stable polymer chains).
DNA is remarkably stable and it's double chain structure means repair is relatively simple. It will probably be chosen as the genetic component for any form of life, but bases on it are kind of arbitrary, so I wouldn't be surprised if we saw different/additional ones.
RNA as an intermediary makes sense to me. I'd be surprised if life found a way to directly translate from DNA. There'd be a lot of problems to work through.
Amino acids are arbitrary. I'd expect we'd see a completely different set of side chains. However, the main backbone has a lot of beneficial features (like hydrolyzing at a non zero but tiny rate without enzymes, being flexible around some axes but having some rigid structure to them, polymerizing easily). I wouldn't expect too many differences with fundamental properties of proteins. Chirality of course has a fifty fifty shot of matching.
All in all, I'd say that life would have very similar low level features (like the chemistry of how things would work for the most part) and similar high level features (like the tendency to form colonies and having sexual reproduction). However, a lot of the middle level features (like having scales or hair or how their immune systems function or how DNA repair is initialized) would be subject to change. If they are intelligent, I would actually expect their nervous systems to look pretty much like ours. Our brains have a pretty straightforward evolutionary path and neuron systems are actually pretty good at approximating a wide range of mathematical functions easily. Of course, it probably wouldn't be NaK pumps and neurotransmitters, but I would expect some form of inter connected cells that can fire and trigger each other.
