Gluconeogenesis. There are no essential carbs.
Discussion
Gluconeogenesis creates glucose from other substances--and then the glucose is leveraged to create ATP via the Kreb's cycle.
Yet the key precursor for normal cellular respiration remains glucose.
Okay, but exogenous glucose is not necessary. And exogenous sugars tend to trigger blood sugar spikes & an emergency response. If you can get what you need & avoid the crazy spikes & crashes it seems like that would be much more desirable.