Taste the rainbow!

"And when his spark was no more..."
Dreadwing telling his brother's fate.

A Spark is the heart of every Cybertronian, which Energon flows through. It is a Transformer's soul and life force wich resides within the chest and is protected by the Laser Core, the spherical shell that protects the Spark and connects it to the neural system. Every Cybertronian has one. If they don't, then they are probably deceased, unless they turn into a Terrorcon. It is shown that a spark has a heart beat like those of humans and that Cybertronians are able to share their split spark with their fellow siblings.