Larry Moran cites a great quote from Bill Martin.
Life is an exergonic chemical reaction. It’s the energy releasing redox reaction at the core of metabolism that makes life run, and throughout all of life’s history it is one and the same reaction that has been running in uninterrupted continuity from life’s onset. Everything else is secondary, manifestations of what is possible when the energy is harnessed to make genes that pass the torch.
If you need any of that explained, read Larry’s summary.
I teach cell biology, and that could be the theme for the entire class. The course has a strictly enforced prerequisite of general chemistry, and students typically take it concurrently with organic chemistry. I tell them from day one that this is basically a chemistry course that focuses narrowly on the reactions that go on inside cells, and yes, life is all about electrons getting cycled through reactions that provide the energy that drives other reactions — it’s mostly redox chemistry.
Focusing on that is also helpful in understanding the origins of life, because it really is just a transition from geochemistry to self-contained bags carrying out continuous redox reactions. I teach the first half-year of our second year core curriculum, and we really do emphasize metabolism and the energetics of the cell, while the second half is basic molecular biology that focuses on DNA/RNA. That makes a lot of sense, because as we all know, metabolism came first, information came second.