Entropy Perspectives of Molecular and Evolutionary Biology

Area of Science:

• Thermodynamics
• Biophysics
• Evolutionary Biology

Background:

• Organisms exhibit low entropy, a characteristic often attributed to life itself.
• Previous studies have not fully quantified the sources and preservation of this low entropy.

Purpose of the Study:

• To revise and quantify the sources of low entropy in living organisms.
• To identify the key biological features contributing to entropy reduction.
• To explore the implications for evolution and disease.

Main Methods:

• Thermodynamic analysis of biomass components.
• Quantification of entropy changes due to metabolic compartmentation and non-equilibrium reactions.
• Evaluation of entropy contributions from DNA, proteins, and energy conversion processes.

Main Results:

• Metabolite compartmentation and non-equilibrium metabolism yield entropy reductions of 1 and 40-50 J K⁻¹ L⁻¹, respectively.
• DNA and proteins contribute minimally to thermodynamic entropy reduction but are key for informational entropy.
• Photosynthesis is the largest entropy producer (2.8 × 10⁵ J K⁻¹ C kg⁻¹); other processes like human metabolism export entropy as heat.

Conclusions:

• Life's low entropy is primarily due to metabolic compartmentation and non-equilibrium reactions.
• Enzymes and genes minimize entropy production, potentially driving evolutionary selection and cancer cell proliferation.
• Understanding entropy dynamics is crucial for comprehending life's fundamental processes and evolution.