Thermodynamics of Biological Systems • Movement, growth, synthesis of biomolecules, and the transport of ions and molecules across membranes all requires energy. • All organisms acquire energy from their surroundings and utilize that energy efficiently to carry out life processes. • In order to study these bio-energetic phenomena we will require knowledge of thermodynamics.
• Thermodynamics: defined as a collection of laws and principles describing the flows and interchanges of heat, energy and matter in systems of interest . • Thermodynamics also allows us to determine whether or not chemical processes and reactions can occur spontaneously.
The ease for a reaction to occur and the direction of reaction is determined by the Laws of Thermodynamics (refer to Mathews and van Holde, 1996 ed. p.62).
• Several basic thermodynamic principles considered including the analysis of heat flow, entropy production, and free energy functions and the relationship between entropy and information.
• In any consideration of thermodynamics, a distinction must be made between the system and the surroundings. The system is that portion of the universe with which we are concerned, whereas the surroundings include everything else in the universe. The nature of the system must also be specified.
• There are three basic systems: isolated, closed, and open. – An isolated system cannot exchange matter or energy with its surroundings. – A closed system may exchange energy, but not matter, with the surroundings. – An open system may exchange matter, energy, or both with the surroundings. • Living things are typically open systems that exchange matter (nutrients and waste products) and heat (from metabolism) with their BCH3101 6 surroundings.
The First Law: Heat, Work, and Other Forms of Energy • It was realized early in the development of thermodynamics