The mitochondrion produce a substance called adenosine triphosphate. It is also known as ATP. It is believed to be our source of energy. ATP's main purpose is to transport chemical energy within cells for metabolism[2]. Metabolism is the sum of the physical and chemical changes that take place in living organisms.
Stem cell harvest. Stem cells used to be harvested from the bone marrow. That has now largely been abandoned in favour of harveting directly from the peripheral blood.
Stem cells, artistic rendering. The type of cells used in stem cell transplants for cancer patients come from a living donor. Not to be confused with embryonic stem cells, which are obtained by destroying a human embryo.