Shea Kathleen Guinto, Peter Julius Dale Inocando*, SooHyun Jung, Jurilla Camille Louise
Department of Biology, University of Santo Tomas, Manila, Philippines
Abstract In this experiment an egg yolk will serve as the sample to isolate lipids and separate them into two classes which is the phosphorylated lipid and the non-phosphorylated lipid. The isolated lipids are then characterized through a series of color chemical tests along with the given standards.
Introduction Lipids (Greek: lipos, fat) are the fourth major group of molecules found in all cells. Unlike nucleic acids, proteins, and polysaccharides, lipids are not polymeric. However, they do aggregate, and it is in this state that they perform their central function as the structural matrix of biological membranes. Substances of biological origin those are soluble in organic solvents such as chloroform and methanol. Hence, they are easily separated from other biological materials by extraction into organic solvents (Voet, D., Voet, J.G., Pratt, C.W. 2012).
Lipids can be categorized to two classes depending on the presence of phosphate. Firstly are the Phosphorylated lipids, also known as Phospholipids which are amphipathic molecules (contains hydrophobic and hydrophilic domains). So that when phospholipids are suspended in water, they spontaneously rearrange into ordered structures exposing the hydrophilic polar head to the water while the hydrophobic groups are buried in the interior to exclude water that makes phospholipids the key structural component of membranes. Most phospholipids contain a diglyceride (glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages.), a phosphate group, and a simple organic molecule. Phospholipids can also be separated into two types: phosphoglycerides and sphinomeylins. Phosphoglycerides are molecules that contain glycerol, fatty acids, phosphate, and an alcohol