Entropy in Biology

Jayant Udgaonkar is Professor and Dean of the Faculty at the National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore. His research interests are in the field of the biochemistry, with particular emphasis on protein folding and unfolding.

The second law of thermodynamics makes no distinction between living and non-living things. Indeed, the concepts of thermodynamics constitute the unifying principles of physics, chemistry and biology.

Processes leading to randomness, disorder, chaos or loss of information would appear to be out of place in the world of biology. Living things are characterized by a very high degree of structure and assembly, whether at the level of molecules, genetic information, cells, tissues, organs, organisms or populations of organisms. On the other hand, the second law of thermodynamics implies the principle that the total entropy, which is a measure of disorder, must increase steadily. Even though thermodynamics itself does not describe processes as a function of time, the second law defines a unique direction of time (time’s arrow) as the direction in which total entropy increases. Nevertheless, thermodynamics does not exclude local exceptions. Living things are local exceptions.

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Address for Correspondence
Jayant B Udgaonkar 
National Centre for Biological Sciences 
Tata Institute of Fundamental Research  GKVK Campus 
Bangalore 560 065, India. 
Email: jayant@ncbs.res.in