Radius of the particle? Diffusion Problem

In summary, gel diffusion is a technique used for analyzing proteins and determining their size. The diffusion constants for various proteins through agarose gel are provided, and it is noted that these values represent the flux of particles, not the change in concentration over time. The diffusion constant can be related to the effective particle radius using the equation D=kT/6πηR, where k is Boltzmann's constant, η is the viscosity, T is the temperature, and R is the radius. Using this equation and given values for temperature, viscosity, and diffusion constants of insulin and lysozyme, the effective radii of these proteins can be calculated. The calculated values for insulin and lysozyme are 5.10
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Homework Statement


One tool in analyzing proteins is gel diffusion. The technique is used to determine the size of the protein being analyzed. The following values are for diffusion through agarose gel.
D (m2/s)
Lysozyme 1.18E-10
BSA 3.90E-11
adolase 6.50E-11
Cu2+ 1.00E-10
glucose 2.90E-10
insulin 4.60E-10
The diffusion constant values are for the flux of particles, not change in concentration over time.





Treating the diffusing particles as spheres moving through a liquid which presents resistance or “drag”, the diffusion constant can be related to the effective particle radius as
D=kT/6πηR

Where k is Boltzmann’s constant, η is the viscosity, T is the temperature in Kelvin and R is the radius. Using 20ºC as the temperature and the above diffusion constants for insulin and lysosyme, Calculate the effective radii of the two proteins. An appropriate value for the viscosity is 100 centipoise = 0.1 Pa•s.

Do for Insulin and Lysozyme... Or just one i did them but i am not sure my answer is correct the seem to high.




Homework Equations



D=kT/6πηR

The Attempt at a Solution


These are the answers i got when i attempted the solution. They seem to big though?

Insulin i got R=1.9g x10^11

Lysozyme i got R=1.552 x 10^10

I just solved for R using the equation above
 
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  • #2
I actually get 5.10x 10^-12 for insulin

and 6.44x 10^-11 for lysozyme


The other answers were 1/R not R

Is this correct because the are "effective"radius?
 

1. What is the radius of a particle?

The radius of a particle refers to the distance from the center of the particle to its outer edge. It is often measured in units such as nanometers or micrometers.

2. How is the radius of a particle determined?

The radius of a particle can be determined through various methods such as microscopy, dynamic light scattering, or by using mathematical models. The specific method used will depend on the size and properties of the particle in question.

3. Why is the radius of a particle important in scientific research?

The radius of a particle is important because it can provide valuable information about the size, structure, and behavior of a particle. This information is crucial in fields such as materials science, nanotechnology, and biophysics.

4. What is a diffusion problem related to the radius of a particle?

Diffusion is the movement of particles from an area of high concentration to an area of low concentration. A diffusion problem related to the radius of a particle may involve studying the rate at which particles of a certain size or shape diffuse in a particular medium.

5. How does the radius of a particle affect diffusion?

The radius of a particle can greatly impact diffusion as smaller particles tend to diffuse faster than larger particles. This is because smaller particles have a larger surface area-to-volume ratio, allowing for more efficient diffusion. Additionally, the shape and surface properties of a particle can also affect its diffusion rate.

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