Lipoprotein structure, illustration. Lipoproteins are structures that transport lipids (fat molecules) in the body. They consist of a shell of phospholipids (orange) surrounding the internal fat molecules (purple), along with stabilising proteins (blue). The phospholipids have a hydrophilic phosphate head pointing outwards and a hydrophobic fatty acid tail pointing inwards. Examples of 'fatty' molecules transported by lipoproteins include triglycerides and cholesterols.