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• #15538
Harrow
Participant

I have a question about diffusion of cells. Why would you expect more of a smaller cell to be diffused in the same period of time than a large cell. Is it just because the smaller ones move faster? And also why would you expect a cell with the same volume as a cubic one, but with a different surface area, to be more diffused than the cubic one?

• #106898
Harrow
Participant

As you may have noticed I’m somewhat of an amateur at biology.

• #106899
Harrow
Participant

In the example with the same volume but different surface area we used a 8x2x1/2 and a 2x2x2.

• #106909
JackBean
Participant

you mean how quickly some substance will diffuse inside the cell?

It’s not about being faster, but being smaller (-> shorter distance). Regarding different shapes, imagine, what’s the longest distance from surface to reach each spot inside.

• #106914
aptitude
Participant

The shape of the cell determines the surface area. The greater the surface area, the more area is available for diffusion. The equation for this is called Fick’s Law of Diffusion:

J = PA (C2-C1)

Where J is the flux due to diffusion, P is a constant, C2-C1 is the concentration difference and A is the area. So the greater the area, the greater the flux due to diffusion, and the more diffusion will occur.

Therefore, in two cells with the same volume, one cubic and one shaped irregularly, the irregularly shaped cell has a higher diffusion flux because it has a greater surface area.

Hope that helps.

• #107056
JackBean
Participant

aptitude: but that is only about diffusion through membrane (or something like that), but the question is probably how long will it take to diffuse into whole cell (volume)