Nutrition Science and Everyday Application - beta v 0.1

LIPID TYPES AND STRUCTURES 261
Phospholipids can also be synthesized by the body, so they don’t have to be consumed in
the diet.
Phospholipids are similar in structure to triglycerides (Figure 5.8). Like triglycerides,
phospholipids have a glycerol backbone. But unlike triglycerides, phospholipids only have
two fatty acid molecules attached to the glycerol backbone, while the third carbon of the
glycerol backbone is bonded to a phosphate group—a chemical group that contains the
mineral phosphorus.
Figure. 5.8. The structural difference between a triglyceride (on the left) and a phospholipid (on
the right) is in the third carbon position, where the phospholipid contains a phosphate group
instead of a fatty acid.
The unique structure of phospholipids makes them both fat- and water-soluble, or
amphiphilic. The fatty-acids are hydrophobic (dislike water), and the phosphate group and
glycerol are hydrophilic (attracted to water).