Researchers have found the Last Universal Common Ancestor (LUCA) had a "leaky membrane" that  answers fundamental questions about human biology.

LUCA, also called the Last Universal Ancestor (LUA) or the progenote, is the most recent organism from which all organisms now living on Earth descend.

Like Us on Facebook

It's, therefore, the Most Recent Common Ancestor (MRCA) of all current life on Earth. LUCA is estimated to have lived some 3.5 billion to 3.8 billion years ago.

Researchers have always been baffled why all cells use the same complex mechanism to harvest energy.

The answer is that LUCA had a leaky membrane that allowed this organism to be powered by energy in its surroundings while keeping intact all the other components necessary for life.

This energy came from vents deep on the ocean floor that emitted alkaline fluids. These fluids when mixed with ocean water neutralized and stopped any build-up of charge that could prevent protons from flowing into the cells, explained Nick Lane from University College London.

"If the first cells had leaky membranes, then protons could enter and be neutralized or leave again, almost as if there was no barrier at all," he added.

This leakiness explains two of biology's greatest mysteries: why all cells use the same strange but complex mechanism to absorb energy and why two types of single-celled organism (bacteria and archaea) have entirely different cell membranes.

Archaea are a kingdom of single-celled microorganisms that have no cell nucleus or any other membrane-bound organelles in their cells. Bacteria and archaea together form the deepest branch on the tree of life.

"From a single basic idea, the model can explain the fundamental differences between bacteria and archaea" he added.

Researchers said bacteria and archaea share many common features like genes, proteins and DNA readings.

Researchers modeled the membrane showing how LUCA's descendants evolved in bacteria and archaea. They're trying to recreate the environment of the sea vents they believe was been present when the building blocks of life were formed.