Sedimentation coefficient: Difference between revisions
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The sedimentation coeffiecient, s, is a way of mathmatically quantfying how a [[Molecule|molecule]] moves when subjected to a [[Centrifugal force|centrifugal force]] usually within a liquid medium. It is calculated by using the following equation: | The sedimentation coeffiecient, s, is a way of mathmatically quantfying how a [[Molecule|molecule]] moves when subjected to a [[Centrifugal force|centrifugal force]] usually within a liquid medium<ref>Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78</ref>. It is calculated by using the following equation: | ||
=== '''s = m(1-vp)/f'''<br> === | === '''s = m(1-vp)/f<ref>Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78</ref>'''<br> === | ||
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It is usually expressed in Svedberg units (S). The larger the S value, the quicker the molecule moves. However, it is not directly proportional to the [[Molecular weight|molecular weight]] of the [[Molecule|molecule]] as is apparent in the equation above. | It is usually expressed in Svedberg units (S). The larger the S value, the quicker the molecule moves. However, it is not directly proportional to the [[Molecular weight|molecular weight]] of the [[Molecule|molecule]] as is apparent in the equation above<ref>Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78</ref>. | ||
Several other aspects affect the sedimentation velocity including [[Atomic mass|mass]], a heavier molecule moves more quickly. Also, if the [[Molecule|molecule]] has a shape that produces less drag, its frictional coefficient will be smaller and hence, will sediment more quickly. And lastly, the [[Density|density]] of both the [[Molecule|molecule]] and the [[Solution|solution]] affects the sedimentation velocity<ref>Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78</ref>. | Several other aspects affect the sedimentation velocity including [[Atomic mass|mass]], a heavier molecule moves more quickly<ref>Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78</ref>. Also, if the [[Molecule|molecule]] has a shape that produces less drag, its frictional coefficient will be smaller and hence, will sediment more quickly<ref>Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78</ref>. And lastly, the [[Density|density]] of both the [[Molecule|molecule]] and the [[Solution|solution]] affects the sedimentation velocity<ref>Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78</ref>. | ||
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Revision as of 17:15, 27 November 2014
The sedimentation coeffiecient, s, is a way of mathmatically quantfying how a molecule moves when subjected to a centrifugal force usually within a liquid medium[1]. It is calculated by using the following equation:
s = m(1-vp)/f[2]
Key:
m= mass of particle
v= partial specific volume
p= density of the medium
f= frictional coefficient
(1-vp) = the buoyant force of the medium
It is usually expressed in Svedberg units (S). The larger the S value, the quicker the molecule moves. However, it is not directly proportional to the molecular weight of the molecule as is apparent in the equation above[3].
Several other aspects affect the sedimentation velocity including mass, a heavier molecule moves more quickly[4]. Also, if the molecule has a shape that produces less drag, its frictional coefficient will be smaller and hence, will sediment more quickly[5]. And lastly, the density of both the molecule and the solution affects the sedimentation velocity[6].
References
- ↑ Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78
- ↑ Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78
- ↑ Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78
- ↑ Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78
- ↑ Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78
- ↑ Berg, J., Tymoczko, J. & Stryer, L. (2011) 'Biochemistry'. 7 edition. New York: W. H. Freeman. pp. 78