biology

Everyone knows mitochondria are the "powerhouse of the cell." Almost no one knows they were once free-living bacteria that struck a deal with our ancestors 2 billion years ago — and still carry their own DNA to prove it.

If DNA is the genome's hardware, RNA is closer to firmware. It reads context, makes decisions, amplifies signals, and silences genes — all without protein intermediaries. The full picture of RNA's information-processing role makes the old 'messenger' label look almost comically inadequate.

Cells were thought to compartmentalize everything in lipid membrane-bound organelles. Then biologists found that key gene-regulation hubs form as liquid droplets via phase separation — the same physics behind oil and water. It's reshaping cell biology.

RNA is supposed to be linear: a start, a message, an end. Circular RNA breaks that rule — looping back on itself to resist degradation and quietly regulate gene expression in ways scientists are still mapping.

Your cells contain a second genome you almost never hear about. Mitochondrial DNA passes exclusively through the maternal line, making it an extraordinary lens on ancestry, evolution, and disease.

You don't store ATP — you recycle it continuously. Your mitochondria spin a molecular motor at 150 revolutions per second to keep the supply flowing. The numbers behind cellular energy are more extreme than most biology textbooks let on.