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NITAAI-Veda.nyf > Soul Science God Philosophy > Science and Spiritual Quest > Section 4 Towards a New Biology > MOLECULAR EVOLUTION: QUANTUM MECHANICS > 1. Introduction

1. Introduction


Are the dynamics of biological systems governed solely by classical physics or could they somehow be influenced by quantum effects? New developments from the convergence of physics, biology and nanotechnology are leading us to critically reexamine our conventional assumptions about the role of quantum physics in life and living systems. Schrodinger in his book What is Life? [1] questioned whether the laws of classical physics were really sufficient to understand life. Schrodinger also wondered whether life, at the most fundamental  level,  could  somehow be  quantum phenomena or at least be influenced by quantum effects? In recent times, such lines of inquiry have, for the most part, been dismissed by mainstream scientists because biological systems are wet and swampy, complex microscopic systems, where it is presumed that quantum coherences would be destroyed much before their effects become relevant to biological processes. It is widely accepted, however, that quantum mechanics must play some role, albeit a trivial one, in life; namely the electronic structures of biomolecules are determined as per the laws of quantum chemistry.


...the 20th century physics developed in the context of inanimate matter has not yet adequately come to terns with life and living systems.


My own quest to understand the physics of living systems is driven, in part, by an inner, intuitive conviction that Living systems provide an excellent laboratory to probe the interplay of matter, energy, and information. I have for the last 15+ years been fascinated with molecular machines that read and write information into molecules of DNA. These nanomotors (matter) transduce chemical free energy into mechanical work as they copy biological information stored in a DNA molecule. These motors can be thought of as information processing machines that use information in their environment to evolve or adapt the way they read out DNA. In ways (as of yet unknown to us), information from their environment can couple into and modulate the dynamics of these nanomachines as they replicate or transcribe genetic information.For the past several years, I have been seeking, with the aid of fundamental physics concepts and emerging experimental tools, to identify and elucidate the various "knobs" in a motor's environment that can exert control on its dynamics as it replicates or transcribes the genetic code. Here, I heuristically examine the role that quantum mechanics may play in influencing the dynamics of the motors as they read/write bits of DNA. I begin by discussing how Wigner's inequalities for a quantum clock impose fundamental constraints on the accuracy and precision with which that nanomotors can read or write DNA. Contrary to implicit assumptions, I discuss how the relaxation times of DNA polymer molecules can be quite long and hence lead to decoherence times that are long compared to the timescale of the internal state transitions in the motor and relevant compared to the timescale associated with the motor reading DNA base. Thus, we argue that it is entirely plausible for quantum effects to influence not only the structure but also the dynamics of biomolecular motors. Lastly, some broader implications of this work are discussed.