Lipoproteins are spherical (VLDL, LDL, HDL) to discoidal (nascent HDL) in shape with a core of non-polar lipids,
triacylglycerols and cholesterol esters, and a surface monolayer, ~20Å thick,
consisting of apoproteins, phospholipids and non-esterified cholesterol,
which serves to present a hydrophobic face to the aqueous phase