Physical Principles: Mechanics and Motion

  • Peter R. Bergethon


Position ... movement ... linked through conservation of energy. If we conceive of the potential energy surface of a system as the set of forces responsible for form in a biological system, then movement or momentum over the surface, the kinetic energy, is function. Movement is kinetic energy, and motion is tied to spatial dimension as a function of time. The arrow of time is related to entropy and is the natural direction of all systems. Time and energy. Position and momentum. These fundamental properties of natural systems are the building blocks of biological form and function. We will see that these properties of systems are complementary and have very important philosophical and epistemological consequences in our understanding of biological systems. We can not understand a biological system if we can not appreciate its motion in state space. The study of motion is the study of mechanics. Whether the motion is an actin molecule or an atomic orbital, there are just several basic motions that sum up the majority of the mechanical actions in all biological systems.


Gravitational Field Buoyant Force Physical Principle Diatomic Molecule Angular Speed 
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Further Reading

Newtonian Mechanics

  1. Cohen B. I. (1981) Newton’s Discovery of Gravity. Scientific American, 244 (3): 166–79.CrossRefGoogle Scholar
  2. Feynman R. P., Leighton R. B., and Sands M. (1963) The Feynman Lectures on Physics, vol. 1. Addison-Wesley Publishing Co., Reading, MA.Google Scholar
  3. Newton I. (1995) The Principia, trans. Motte A. Prometheus Books, Amherst, NY.Google Scholar
  4. Warren W. S. (1993) The Physical Basis of Chemistry. Academic Press Co., San Diego.Google Scholar

Frictional Coefficients and Centrifugation

  1. Cantor C. R. and Schimmel P. R. (1980) Biophysical Chemistry, vol. II. W. H. Freeman, New York.Google Scholar
  2. Cieplak M., Smith E. D., and Robbins, M. O. (1994) Molecular origins of friction: The force on absorbed layers. Science, 265: 1209–12.PubMedCrossRefGoogle Scholar
  3. Freifelder D. M. (1982) Physical Biochemistry: Applications to Biochemistry and Molecular Biology, 2d ed. W. H. Freeman, New York.Google Scholar
  4. van Holde K. E. (1985) Physical Biochemistry, 2d ed. Academic Press, New York.Google Scholar

From the “Who Said Biophysics Isn’t Fun?” Department

  1. Roberts T. J., Marsh R. L., Weyand P. G., and Taylor C. R. (1997) Muscular Force in Running Turkeys: The Economy of Minimizing Work. Science, 275:1113–15. An elegant application of biophysics to the mechanics of running. Does a turkey pogo stick or pump its way across the barnyard?PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • Peter R. Bergethon
    • 1
  1. 1.Department of BiochemistryBoston University School of MedicineBostonUSA

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