Name ___________________________________ Date ______________ Period _____________
Chemistry of Lipids and Proteins
Part A. Lipids
Examine the structural formula of glycerol.
1. What elements are present in glycerol? ________________________________
2. Are there any elements in glycerol that are not in carbohydrates? _____________
3. What is the molecular formula for glycerol? C__H__O__
4. As in carbohydrates, are there twice as many hydrogen atoms as oxygen atoms in
glycerol? _____
Fatty Acids
Butyric Acid
Lauric acid
Caproic acid
5. What elements are present in all fatty acids?
____________________________________
6. a. What is the molecular formula for butyric fatty acid? C__H__O__
b. What is the molecular formula for lauric fatty acid? C__H__O__
c. What is the molecular formula for caproic fatty acid? C__H__O__
7. Are there EXACTLY twice as many hydrogen atoms as oxygen atoms in a fatty acid? ____
8. What pattern appears in the fatty acid molecules regarding the number of oxygen atoms?
_____________________________________________________________________
9. Note the end of butyric acid containing the oxygen atoms. This special end arrangement of
carbon, hydrogen, and oxygen is called a carboxyl group.
10.
a. List a similarity between glycerol and fatty acids. __________________________
______________________________________________________________________
b. Do fatty acids and glycerol both contain a carboxyl group? ___________________
11.
a. How many glycerol molecules are needed to form a fat molecule? _______________
b. How many fatty acid molecules are needed to form a fat molecule? ______________
Part B. Proteins
Amino acids are the building blocks of proteins. If you string different amino acids together,
you can make different proteins.
Examine the structural formulas of the four representative amino acids shown.
Glycine
Alanine
Valine
12. The element nitrogen is present in amino acids. Is nitrogen present in fats and
carbohydrates? ____
13. a. What is the molecular formula for the amino acid glycine? C__H__O__N__
b. What is the molecular formula for the amino acid alanine? C__H__O__N__
c. What is the molecular formula for the amino acid valine? C__H__O__N__
14. Are the molecular formulas for all amino acids the same? __________________
15. What end arrangement of atoms is present in amino acids that is also present in fatty acids?
___________________________
Another end arrangement in all amino acids consists of a nitrogen atom and two hydrogen atoms.
This groups is called an amino group.
16. Do all the structural formulas for the above amino acids have amino groups? __________
Analysis:
1. a. What 2 molecule types are needed to form a molecule of fat? __________________
__________________________________________________________________
b. How many of each type of these molecules are needed to form a molecule of fat?
__________________________________________________________________
2. What chemical elements are found in all fats? ________________________________
3. What small molecule is needed to form a large protein molecule? __________________
4. What chemical elements are found in all proteins? _____________________________
5. If fatty acids and amino acids both have carboxyl, when a molecule has a carboxyl group,
what must that molecule be then?
___________________________________________________
Place a check in the box if the molecules on the top have the descriptions on the side.
Glycerol
Carbon present
Hydrogen present
Oxygen present
Nitrogen present
Exactly twice the amount of H as O
Has a carboxyl group
Has an amino group
Molecules join to form proteins
Molecules join to form lipids
One molecule loses 3 OH ends
Fatty
acids
Amino
acids