Urea/EDTA treatment

[Adz795]

Q. Urea or EDTA treatment of membranes leads to the dissociation of:
1) Peripheral proteins
2) Integral proteins
3) Cholesterol molecules
4) Phospholipids

I don't have any understanding of Urea/EDTA treatment of membranes. I have never come across it. To answer this question I need to know it. Please tell me a resource where I can find details of this process or explain me please.

Thank you.

[JackBean]

urea denatures proteins, EDTA is chelator (it binds strongly metal ions), however, to my knowledge, they shouldn't affect lipids