Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
240 Chemistry: Matter and Change
Solving Problems: A Chemistry Handbook
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER 23
Triglycerides Animal fats and plant oils are made up primarily
of triglycerides, molecules in which three fatty acids are bonded
to a glycerol molecule by ester linkages, as shown in the following
diagram.
Phospholipids are triglycerides in which a polar phosphate group,
instead of a third fatty acid, is bonded to the glycerol. Cell membranes consist of a double layer of phospholipid molecules.
Other Lipids Another class of lipids, steroids, consists of compounds whose basic structure is very different from those of other
lipids, as shown below. Cholesterol, vitamin D, and some hormones
are steroids.
Practice Problems
13. How do saturated and unsaturated fatty acids differ in molecular
structure?
14. How does the basic structure of steroids differ from that of fatty
acids and triglycerides?
Basic Structure of a Steroid
▲
Triglyceride
—
—
O
CH — O — C — (CH 2 ) 16 — CH 3
—
—
O
CH 2 — O — C — (CH 2 ) 14 — CH 3
—
—
O
CH 2 — O — C — (CH 2 ) 18 — CH 3
▲