<prompt> Which has least density?LDLChylomicronsHDLVLDL  <response>: Classification as per hydrated density: Pure fat is less dense than water. As the propoion of lipid to protein in lipoprotein complexes increases , the density of the macro-molecule decreases. Use of the above propey has been made in separating various lipoproteins in plasma by ultracentrifugation. Svedberg units of floatation Sf unit: The rate at which each lipoprotein floats through a solution of NaCl Sp.gr. 1.063 is expressed as Svedberg units of floatation Sf.Sf unit: One Sf unit is equal to 10-13 cmSdyneg at 26degC. Gofman and colleagues 1954 separated lipoproteins by ultracentrifugation into four major density classes:Chylomicrons: Density lowest-floatsVery low-density lipoproteins VLDL or VLDLPLow-density lipoproteins LDL, andHigh Density Lipoproteins HDL: settles below.LDL: It has been fuher divided into LDL 1, IDL intermediate density lipoprotein and LDL-2HDL: It has been fuher separated into HDL-1 this fraction is quantitatively insignificant, HDL-2 and HDL-3. Recently HDL c has been described.Ref: Textbook of Medical Biochemistry 8th Edition Dr Brig MN Chatterjea, Rana Shinde, page no: 444 