About 1.5 billion years ago, tiny visitors came to live inside the cells that later evolved into all plant and animal life -- including humans. Those visitors were mitochondria, small organelles whose ...

Mitochondria are “the powerhouse of the cell” (or so every fifth grade biology book will tell you) because they use aerobic respiration to generate ATP, the molecular form of energy that enables ...

Mitochondria have their own DNA, but the 13 genes in human mitochondria -- along with DNA sequences for tRNAs, rRNAs and some small peptides -- are massively overshadowed by the 20,000 genes in the ...