After years of manic growth indicated by frequent cell division, the human cell slows down a little and enters a phase known as senescence. This was believed to contribute to the ageing process.
New research, however, suggests this slowing down is probably an important "anti-cancer mechanism", suggested Dr Richard Faragher of the University of Brighton. Senescence is probably as important as programmed cell death, a defence mechanism whereby cells commit suicide.
Senescence does not mean at some point we stop growing and start ageing. A small number of cells continue to divide and form new cells over very long periods of time. "Thus by the end of its lifespan, an organism performs a surprisingly large amount of cell turnover," he noted.
The 1997 Nobel Laureate for chemistry, Sir John Walker, outlined his latest work on the production of ATP (adenosine triphosphate) in the cell to the Biochemical Society last night. ATP is an invaluable form of "storable energy", generated in large quantities for use when needed.
The average human creates their own bodyweight of ATP each day, though it is broken down and reconstituted, usually in the mitochondrion, the powerhouse of the cell. His work in Cambridge succeeded in describing the mechanism by which an biological catalyst, known as ATP synthase, operates in creating ATP. He also worked out the enzyme's structure.