Physics & Biophysics: Exploring Intersections

[kldickson]

Let me know if this is the wrong forum.

I'm a neurobiology student and I've recently come across more information about biophysics, but from what I've read, it's a little difficult to understand fully how physical principles are applied in the field.

For example, there's structural biophysics, systems neuroscience (which is a central topic in my curriculum and which I'm quite familiar with, but have mostly gotten my grounding in the biological aspects of it and not been exposed to much of the physics side of it beyond, say, electrophysiology), molecular microscopy, cell signaling and physiology, computational biology, bioelectronics, and biomechanics, which are some pretty broad fields within not only biophysics but within other fields as well. I can infer to an extent where physics applies - it's much more obvious in systems neuroscience and cell signaling (electrophysiology), but less so in, say, structural biophysics and biomechanics. (Then again, the extent of my physics classes is two semesters of introductory physics, which is the only physics requirement for my degree and is all the physics I can reliably squeeze into my curriculum, which has a lot of requirements)

I have some idea of how physics intersects with all of this, but I want to hear from people who have a better understanding of the physics aspects of this.

 

[pjfoster]

I'm relatively new to biophysics as well, but I've worked in a biophysics lab for the past summer using flourescent resonant energy transfer to understand the movements of a particular motor protein. Biophysics is a very hard subject to pin down. I've heard it said that "Biophysics is what biophysicists are doing". Not very helpful. Anyway, the physics aspect seems to apply in two parts. First is in instrumentation. For example energy transfer technique I've been using has to do with radiationless transfer of energy in a dipole-dipole interaction. Our lab also makes use of optical tweezers to measure forces on a single-molecule level. The other way that physics seems to apply is through the mathematical modeling. For example, from what I understand one of the best models of how DNA behaves is through the "freely joined chain model" where DNA segments are thought of as infinitely rigid rods, an imaginary object that should be common to physicists. I've also heard of various things being modeled as Hookean springs, another basic physics concept that is applied to biological systems. In general, it seems that biophysics involves modeling biological problems as the simplest well understood physical systems available.

 

[Andy Resnick]

Biophysics can mean different things to different people. Some topics include the physics of biochemical reactions (reaction rates), protein structure and folding dynamics, fluid mechanics of swimming and flying, organ systems, hemodynamics, mechanotransduction (what I study), membrane physiology, cell motility and structural dynamics, and more.

Then there's the instrumentation- mass spectrometry, electrophysiology, microscopy, laser tweezers, computational methods (markov processes, molecular modeling, fluid flow), etc. etc.

There's considerable blurring between biophysics, physiology, molecular biology, medical physics, etc. Sometimes people say 'biophysics' is the application of quantitative physical science to biological systems, while 'physical biology' is the application of biological methods (think evolution and mutation) to physical systems.