Life, the universe and mitochondria

Power, sex and suicide. Mitochondria and the meaning of life. 

Nick Lane  

Oxford, UK: Oxford University Press | 2005 | 354 pp | ?18.99 (HB) | ISBN 0192804812 

Reviewed by  Tony Onyett

The title of this book may be somewhat sensational, but the role of mitochondria in biology lives up to this billing. Most of us were taught at school that mitochondria are the energy powerhouses of the cell, containing convoluted cristae where respiration uses oxygen to generate the power for cellular function. 

The early chapters in this book deal with the bioenergetic mechanisms in the mitochondria - the coupling of electron transfer to ATP synthesis in oxidative phosphorylation and in photophosphorylation. The development of the ’chemiosmotic theory’ propounded by Peter Mitchell, which led to his 1978 Nobel prize for chemistry, is explained in great detail. But power is only part of the story and most of this fascinating book by biochemist Nick Lane deals with recent research into the sex and suicide aspects of this important organelle. 

Mitochondria were once free-living cells, perhaps derived from bacteria, a theory first proposed by Lynn Margulis in 1967. With time they were subsumed into larger cells to their mutual advantage. In sexual reproduction, employed by most multicellular lifeforms, sperm contains nuclear DNA only, while the egg also contains mitochondrial DNA. The reason that we have two sexes at all may be due to a need to maintain a match between mitochondrial and nuclear genes. The theory of our mitochondria being largely female in descent is a controversial one. 

Finally, mitochondria are involved in the process of cell suicide or apoptosis - a term coined in 1972 by John Kerr, Andrew Wyllie and Alistair Currie. Under mitochondrial control, apoptosis is essential to the development of multicellular organisms and the elucidation of its molecular mechanisms earned the 2002 Nobel prize for medicine for Sydney Brenner, Robert Horvitz and John Sulston from the Laboratory of Molecular Biology in Cambridge, UK. Any breakdown in the balance of this delicate process leads to cancer on the one hand, and degenerative processes and aging on the other. Lane draws the controversial conclusion that mitochondria must therefore hold the key to avoiding degenerative diseases and postponing the ageing process. 

This book could be heavy going in places for those without a thorough grounding in biochemistry and it jumps about too much from one process to another and back again. It is, however, full of fascinating insights into the origins of life and the way that mitochondria play key roles from the moment of conception to the moment of death. 

Is there anything mitochondria cannot do?