Bioenergetics deals with the very first energy transformation steps performed by living cells. Increased dissipation is the primary effect of processing external energy packages. Enzyme-supported charge separation is the minor but essential outcome for maintaining Life. This book explores the usefulness of dissecting the entropy production of enzymes involved in cellular defenses, fermentation, respiration, and photosynthesis, assuming that tightly regulated dissipation is the hallmark of Life.

Researchers, educators, and students of life sciences (biophysics, bioinformatics, enzymes as nanomotors) can find in this text many examples of how we can use the interdisciplinary approach to study cells' virtuoso ability to connect the microscopic to the macroscopic world.

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We all know two things about Life on Earth. The first is that almost all Life depends on photosynthesis. The second is that the efficiency of photosynthesis is surprisingly low – less than 10%. What happens with more than 90% of harvested light energy, which is not used for organic synthesis? It ends up increasing the entropy of the Universe. One visible light photon from Sun is converted by Life into about 20 invisible infrared photons for heating Life's environment. That irreversible process is named entropy production (dissipation). There is no evolution without entropy production. Biological energy transformations (bioenergetics) and biological evolution would be impossible without entropy production as their major result. On the other hand, we know from the Second Law of Thermodynamics that entropy increase caused by thermodynamic evolution ends up in the thermodynamic equilibrium when Life is impossible.

Scientists often have one initial highly motivating goal (as finding a cure for cancer) for devoting countless hours, days, and years to achieve it. My lifelong goal was to find the solution for the paradox of biological evolution leading at the same time to ever more complex low entropy structures and an acceleration of the entropy increase (disorder) in the Universe. After publishing about 20 scientific papers on that topic, the time has come to gather all the new insights into a single book. The book title: Bioenergetics, and subtitle: A Bridge across Life and Universe, does not reveal the unifying concept, which is its focus. Let me explain it. I elaborate in the book how rivers of Life forever change Life and its environment by coupling biological to thermodynamic evolution. The former evolution speeds up the latter. The book explores the usefulness of dissecting the entropy production of enzymes involved in cellular defenses, fermentation, respiration, and photosynthesis, assuming that tightly regulated dissipation is the hallmark of Life.

I found unrealistic aspects of minimal and maximal principles for total entropy production when applied to bioenergetics and enzyme kinetics. Neither does justice to strict regulation of overall entropy production level, which is obligatory for the survival of a cell or organism in an often hostile environment. A natural tendency for maximal possible increase of entropy production is allowed by the cell to take its course only in catalytic steps subjugated to biological needs. Thus, we should maximize partial entropy production associated with these biologically productive rate-limiting steps to increase an overall entropy production instead of maximizing total entropy production. Core chapters of my monograph on bioenergetics argue for a tight connection among increased overall entropy production, increased turnover number (catalytic constant), and increased enzyme efficiency after crucial catalytic steps have been optimized for transitional (step-specific) maximal entropy production. That is a natural solution for the question of how nanocurrents produced by enzymes and bioenergetic systems can be optimally channeled toward Life’s preservation and multiplication. After comparing theoretical and experimental results, I show in the book that biological evolution nearly achieved such optimization for enzymes performing the free-energy transduction. For simpler substrate to product converting enzymes, additional catalytic improvements can be achieved, despite biochemical description for some of them as “perfect enzymes.” There are obvious ramifications for the rational design of artificial enzymes as a possible experimental spin-off of these ideas. Theoretical improvements are also possible if our theorem on maximal partial entropy production for a transition between functional states can be generalized by taking into account fluctuations.

An overview of membrane proteins introduces a reader to main protein players in the biological free energy transduction. Initial chapters expose the essence of bioenergetics with its historical background. Each chapter is a self-contained unit with a glossary and selected references for further reading. The book explains why I am offering the following definition of Life:

Life is the process of decreasing available forces X_a through primary and secondary fluxes J_a, J_s. It results mainly in additional dissipation and partially into charge separation, chemical transformations, and the accumulation of power-producing couples X_sJ_s for self-maintenance and reproduction – the processes that increase the complexity of Life and the entropy of Life's environment.