About the structure and biological function of TAG Structure. Triacylglycerols (triglycerides, TAG, or TG) belong to the group of glycerol esters within the glycerolipids. Their structure consists of a glycerol backbone linked to three fatty acids. The fatty acids can be of variable length, hydroxylated, and contain double bonds. Function. Triacylglycerols are a great source … Continue reading Triacylglycerol