Wait..Mitochondria is* a bacteria?!

Have you ever wondered what powers your cells? It turns out that tiny structures inside them, called mitochondria, are like little energy factories. But here’s the crazy part: mitochondria were once their own living cells, kind of like bacteria. It sounds like science fiction but it actually happened, and it changed life on Earth forever.

Mitochondria Used to Be Free-Living Bacteria

A long time ago, before complex cells existed, there were simple single-celled organisms floating around. One of these cells swallowed a bacteria, but instead of digesting it like food, it kept it alive inside. This bacteria was special because it could make energy efficiently. Over time, the two cells started living together in a partnership.

How Two Cells Became One Team

Imagine you have a phone and a power bank. The phone needs power to work, and the power bank stores energy. If you connect them, both benefit: the phone gets charged, and the power bank gets carried around safely. That’s kind of what happened when one cell absorbed the bacteria. The host cell got a steady energy supply, and the bacteria got a safe place to live with food to eat.

Proof That Mitochondria Were Once Independent

Scientists found some cool clues that mitochondria were once separate cells:

• Mitochondria have their own DNA, which is different from the DNA in the cell’s nucleus. This DNA looks a lot like bacterial DNA.

• They have double membranes. The outer membrane came from the host cell, and the inner one is from the original bacteria.

• Mitochondria divide on their own, kind of like bacteria do, instead of being made by the cell like other parts.

  
  

These facts support the idea that mitochondria started as independent bacteria and became part of a bigger cell through a process called endosymbiosis.