Introduction to Biophysics. I.

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Introduction to Biophysics. I.

• Jiunn-Ren Roan

Fall 2004
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What is biophysics?
Lets see what a book published in 1983 says
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My favorite definition
A biophysicist talks physics to the biologists
and biology to the physicists, but when he
meets another biophysicist, they just discuss
women.
From A. L. Mackay, A Dictionary of Scientific
Quotations
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Everyone has his/her own definition of
biophysics. Perhaps the best way to answer the
question is to see what biological problems
physicists are studying.
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Why study biophysics?
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Some aspects of biophysics. 1.

• Biophysics at the molecular level
• Determination and prediction of protein
  structures
• Single-molecule spectroscopy
• Molecular motors
• The protein folding problem
• DNA-protein interactions

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Some aspects of biophysics. 2.

• Biophysics at the cellular level
• Transport within and across cell membranes
• Structure and properties of cell membranes
• Propagation of neural signals
• Cytoskeleton and cell movements
• Cytokinesis

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Some aspects of biophysics. 3.

• Biophysics at multicellular and higher levels
• Tissue and biomedical engineering
• Physical and mathematical physiology
• Biomechanics and biorheology
• Population dynamics and theory of evolution
• Mathematical epidemiology

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Another way to define biophysics is to see what
some important biophysicists did and how their
background in physics helped them.
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Important physical biologists and
biophysicists (and how they developed their
careers)

• Archibald V. Hill (1922 Nobel Prize)
• (Biography http//nobelprize.org/medicine/laureat
  es/1922/hill-bio.html)
• Linus C. Pauling (1954 Nobel Prize)
• (Biography Force of Nature The Life of Linus
  Pauling)
• Francis H. C. Crick Maurice H. F. Wilkins
  (1962 Nobel Prize)
• (Cricks autobiography What Mad Pursuit
• Wilkins autobiography The Third Man of the
  Double Helix)
• Max F. Perutz John C. F. Kendrew (1962 Nobel
  Prize)
• (Perutzs obituary by Crick Phys. Today 55, 62
  (2002)
• Perutzs and Kendrews biographies
  http//nobelprize.org/chemistry/laureates/1962/ind
  ex.html)
• Alan L. Hodgkin Andrew F. Huxley (1963 Nobel
  Prize)
• (Hodgkins autobiography Chance Design
• Huxleys biography http//nobelprize.org/medicine
  /laureates/1963/huxley-bio.html)
• Max Delbrück (1969 Nobel Prize)

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• Allan M. Cormack Godfrey N. Hounsfield (1979
  Nobel Prize)
• (Autoiography http//nobelprize.org/medicine/laur
  eates/1979/index.html)
• Aaron Klug (1982 Nobel Prize)
• (Autobiography http//nobelprize.org/chemistry/la
  ureates/1982/klug-autobio.html)
• Erwin Neher Bert Sakmann (1991 Nobel Prize)
• (Autobiography http//nobelprize.org/medicine/lau
  reates/1991/index.html)
• Paul D. Boyer, John E. Walker J. C. Skou (1997
  Nobel Prize)
• (Autobiographies http//nobelprize.org/chemistry/
  laureates/1997/index.html)
• John B. Fenn, Koichi Tanaka Kurt Wüthrich
  (2002 Nobel Prize)
• (Autobiographies http//nobelprize.org/chemistry/
  laureates/2002/index.html)
• Peter Agre Roderick MacKinnon (2003 Nobel
  Prize)
• (Autobiography http//nobelprize.org/chemistry/la
  ureates/2003/index.html)
• Paul C. Lauterbur Peter Mansfield (2003 Nobel
  Prize)

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So, as a physics major, what do you have to learn
if you are a biophysicist-wannabe?
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molecular biology
cell biology
physiology
organic chemistry
ecology

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Purpose of this course
To help physics majors learn basic biochemistry
and physical biochemistry, so that they will at
least have no fear when they encounter bio-jargon
in literature and, hopefully, will begin to
appreciate biological sciences.
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Advice of a successful biophysicist, Crick
What gives biological research its special
flavor is the long-continued operation of natural
selection. Another key feature of biology is
the existence of many identical examples of
complex structures. If this were produced by
chance alone, without the aid of natural
selection, it would be regarded as almost
infinitely improbable. It is thus very rash to
use simplicity and elegance as a guide in
biological research. Physicists are all too
apt to look for the wrong sorts of
generalizations, to concoct theoretical models
that are too neat, too powerful, and too clean.
Not surprisingly, these seldom fit well with the
data. one must try to see through the clutter
produced by evolution to the basic mechanisms
lying beneath them, realizing that they are
likely to be overlaid by other, secondary
mechanisms. What seems to physicists to be a
hopelessly complicated process may have been what
nature found simplest, because nature could only
build on what was already there.
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References

• F. H. C. Crick, What Mad Pursuit, Basic Books
  (1988).