# Some Calculation Questions Regarding Biophysics on Lipids?

by Liposomes on November 1, 2011

I need help on this 2 questions: I'd like to know the steps or formulas to solve this 2 questions:

Labelling experiments have shown that phospholipids (PL) diffuse within the cell membrane, and the diffusion constant, D, for a PL in a membrane is 7x10^ (-13) m2.ms-1. Is it true that it would take more than 1041.784 μs for a PL molecule to travel from one point to the liposome to its opposite ( &pi radians away) in a liposome of 781 nm diameter?

I know that I need to find the displacement or the area divided by (the product of 4 and the diffusion constant) to get the time. Do i find the displacement or area and how do i find them given that the diameter of the liposome is 781nm. also, does the direction pi radians got to do with the answer that I would be getting?

The second question is :

the average no. of molecules of DMPC required to form uni lamelar liposome with diameter 132nm is more than 2.69 x 10 ^5. Assuming that both leaflets contain the same no. of molecules and the cross section area of each lipid molecule is 45 angstrom^ (2)

the surface area of a sphere in the context of a lipid or rather in this case, lipids in liposomes is 8x pie x radius^(2) or is it 4x pie x radius^(2). If I'm able to find the area, I could divide this area by the cross section area of each lipid molecule to get the number of molecules of DMPC

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diameter
#### Related Lipsome | Lipid Vesicles Entries

{ 1 comment… read it below or add one }

see the Pearson’s chi square test

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