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How important is Physics, if I want to be Bio Major?

  1. Mar 18, 2009 #1
    I plan to focus on Gentics, and I am just finishing my freshman physics, I haven't got to my bio or chem classes yet..

    So I was wondering, how important is physics and our understanding of it, if we want to go into the field? I can do pretty decent on the tests and understand the formulas and how most things work.

    But when I dwelve deeper... like trying to understand magnetic constant, and most of the stuff they just give to us but don't explain, I kinda get lost.

    For example.. We learned that to find the force between two charged particles, you have to use the equation "(ke x q1 x q2) / r2). The book and class doesn't go into how we got ke or what ke is.

    So does it help a lot to try and understand stuff like that on my own, as preparation for when I get to the bio and chem classes?

    Edit: Didn't know how to use properly use the power sign on the forum until now.
    Last edited: Mar 19, 2009
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  3. Mar 19, 2009 #2

    Andy Resnick

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    I deal with this prejudice a lot- that somehow, physics is not relevant to "real" biology.

    There are plenty of biologists who see the value and relevance of physics and how it can inform biological research- not just the methods, but also analysis and concepts. Unfortunately, the reality is that what is presented in freshman physics courses is not relevant to biology except in a uselessly abstract sense. By the time the physics is advanced enough to deal with biology (for example, the Nernst equation), the biology/biochem majors are long gone. And the only things they remember from physics are that "there's a lot of equations and it doesn't make any sense".

    Genetics is starting to take a lot of cues from computational methods-proteome (*-omics) analysis, for example. Quantitative biology is also becoming more common, and that means (besides statistics) more mathematical analysis is 'acceptable'.

    To summarize, I don't think it's useful to flog freshman physics in great detail (although your equation is incorrect- that's worth correcting...), but definitely try to understand the basic concepts: harmonic oscillation, an RC circuit, equilibrium, dimensional analysis, basic math (e.g. derivative), etc. Those will serve you well. That, and get up to speed on bioinformatics.
  4. Mar 19, 2009 #3
    I think to be honest it's a case of one or the other with chemistry and physics alongside biology, when it shouldn't be....you could do all three and it would help you massively. However, I still think the focus should be only chemistry with biology if you want a biological based education...but I am talking from an English education point of view, so America may well be very different.
  5. Mar 19, 2009 #4
    My background is more in physics, and I'm just beginning to read in molecular biology. It seems that with the recent explosion of genetic sequencing data, studying biology in a mathematically rigourous way is becoming doable. Systems molecular biology, networks of interacting genes, proteins etc, complex dynamical networks.. I think some ideas from statistical mechanics may be related...
  6. Mar 20, 2009 #5


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    I'd say a bio/biochem major should have taken introductory physics. I've taught labs in that for biochem students, for whom it was mandatory and some of them did ask "why do we need to know this?". Well, I explained where what they were learning could be applied directly to their subject and they walked away asking "Why didn't our lecturer tell us this?".

    Really, if you can't see the relevance, it's because the teacher hasn't given you relevant examples. It's easy for a physicist to just give the 'usual' examples of things from physics books, like vibrating strings and charged spheres and all that, rather than things that are relevant to biology.

    Well it's just a constant really. You can determine it experimentally. 'Deeper' insights into what it is and why it has the value it does is something you'd really have to become a full-fledged physicist to get into. The important thing with Coulomb's equation is that you now know the force is inversely proportional the the square of the distance, and proportional to the product of the charges. So ke is just a measure of the electromagnetic force in terms of our 'human' units, coulombs and meters.

    Now to give an example of how this is relevant to biology, you can look at electrophoresis. Given that F = ke*q1*q2/(r^2) and acceleration is F/m, the speed of particles moving through your electrophoresis gel will depend on their charge and inversely on their mass.

    Another example of electrostatic forces in biology is the potential difference (150-200 mV IIRC) across the inner mitochondrial membrane, which comes from hydrogen ions being 'pumped' across it in the electron transport chain. This potential difference then powers ATP synthase.
  7. Mar 20, 2009 #6

    Andy Resnick

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    I was waiting for this example to come up. Actually, I would claim that having a grounding in physics help to understand a lot more than the above; for example, that the molecule's *shape* as well as mass has a role in gel electrophoresis (and sucrose gradient centrifugation), and that explains the need to denature proteins first. Understanding the physics helps motivate the experimental protocol, development of controls and standards, and interpretation of results.
  8. Mar 20, 2009 #7
    http://insti.physics.sunysb.edu/~siegel/history.html" [Broken]

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  9. Mar 21, 2009 #8


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    I could see how p-chem could be useful in microbiology which could lead one to QM. A lot of medical machines are based heavily on physical principles that I studied in QM (like the MRI).
  10. Apr 1, 2009 #9


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    A lot of physiology (i.e., electrophysiological recording from cells) and neuroscience (especially any kind of neuro-imaging work) requires understanding and applying physics. It actually makes it difficult for people to find good grad students on some projects, because physics majors don't have enough biology, and biology majors don't have enough physics. There are many universities where biology majors are required to take both chemistry and physics courses, but they usually wimp out on the physics, and others don't appreciate the value of physics and leave it out.
  11. Apr 3, 2009 #10

    Andy Resnick

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    I totally agree, and bright students that can 'bridge the gap' (in either direction) will be well-placed for future employment.
  12. Apr 24, 2009 #11
    I think this is more for sociological reasons than anything else... but electrophysiologists are generally much more expected to have an understanding of physics than are neuroimaging people.
  13. Apr 24, 2009 #12


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    If a law of physics is fundamental, there is no explanation for it, since it explains everything else. So you can treat ke as a fundamental fudge factor. The more important thing to know is that Coulomb's law is only an electrostatic law, and you need corrections for moving charges, but that these corrections are usually very small for most of biology. I wouldn't bother too much about fundamental physics for biology - no matter how fundamental you get in physics, there's always a more fundamental layer of laws - unless string theory happens to really be correct! For genetics, understanding the chi-squared test is much, much more important - you can do biology without Maxwell's equations, but not without statistical inference.
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