"Mitochondria uses ketones (fat) to generate energy via the electron tealnser chain, not sugar."

I think you meant electron transport chain. The electron transport chain (ETC) in the mitochondria passes electrons from NADH and FADH2 via a series of electron donors and acceptors to eventually reduce oxygen to water. In the process, the energy created by the ETC is used to generate a proton gradient across the mitochondrial membrane, which in turn enables ATP synthase to generate the real energy currency in the cell, ATP. This is called oxidative phosphorylation. 

Sugars can be used to make ATP. Proteins (amino acids) can be used to make ATP. Fatty acids can be used to make ATP. Ketone bodies can be used to make ATP. The energy from sugars, amino acids, fatty acids, and ketone bodies ALL use the electron transport chain to produce ATP via oxidative phosphorylation. Your statement that implies that the mitochondria uses ketones (fats) but not sugar to generate energy is 100% incorrect.  Sugars, fatty acids, amino acids, ketone bodies......these all generate acetyl-CoA and/or other intermediates of the citric acid cycle (aka Kreb's cycle or tricarboxylic acid cycle). It is this cycle that converts the energy from oxidation of sugars, fatty acid, ketone bodies and amino acids into NADH and FADH2, which then feed into the ETC to create the proton gradient and ATP via oxidative phosphorylation as described above.

BTW, I majored in Biochemistry as an undergrad, got my PhD in Biochemistry, was a teaching assistant for a Biochemistry course for Veterinary Medicine students, and have been doing biochemistry related research for over 20 years. 

"Just as a science tidbit, we inherit out mitochondrial genes from our mothers not from both, mothers & fathers!"

Just FYI, that old school notion of maternal only mitochondrial DNA inheritance has recently been challenged. 

Biparental Inheritance of Mitochondrial DNA in Humans

https://www.pnas.org/content/115/51/13039

Mitochondrial DNA can be inherited from fathers, not just mothers

https://www.nature.com/articles/d41586-019-00093-1