By Jonathan Zilberg
Guest Contributor
The Krebs cycle. It’s like a holy grail to
me. For some reason this biochemical system
among all others has held my attention across
the years. Ever since the first time I learned
about it in high school I’ve been entranced. I
remember that day in 1978 as if it were yesterday. A student biology teacher, almost beside
himself with excitement, keeps blurting out,
“this, this is the stuff of life,” while carefully
drawing out the cycle that leads to the production of biological energy within the powerhouses of eukaryotic cells, the mitochondria.
I know I’m not alone in this fascination; ask
almost any biochemist. Oscillating directional
synergistic membrane-based systems, oxidative
phosphorylation, chemiosmotic systems, energy
cascades—oh, for the love of science.
The Krebs cycle is a linked series of chemical reactions that store biological energy in the
form of a molecule called ATP. Virtually all life
forms depend on the Krebs cycle to extract energy from ingested food. Even bacteria, which
lack mitochondria, have their own version of
the cycle. The scientist from whom it takes
its name, Hans Adolf Krebs, conceptualized it
in 1937 and won a Nobel Prize for the work in
1953. It is also called the citric acid cycle because in it, one molecule of citric acid is broken
down and then regenerated through a series of
eight biochemical steps.
The importance of all that goes on within
the mitochondria is highlighted by the severity of mitochondrial diseases, in which the
function of the mitochondria becomes increasingly compromised. Problems with the Krebs
cycle are just one of many potential causes for
mitochondrial diseases, which can affect the
nervous system, muscles, hearing, and vision.
These con