Chemical Composition of the Body
3. Describe the distinguishing characteristics of the three classes
of essential chemical elements found in the body.
4. How many covalent bonds can be formed by atoms of carbon,
nitrogen, oxygen, and hydrogen?
5. What property of molecules allows them to change their three-
6. Describe how an ion is formed.
7. Draw the structures of an ionized carboxyl group and an
ionized amino group.
8. Deﬁ ne a free radical.
9. Describe the polar characteristics of a water molecule.
10. What determines a molecule’s solubility or lack of solubility in
11. Describe the organization of amphipathic molecules in water.
12. What is the molar concentration of 80 g of glucose dissolved in
sufﬁ cient water to make 2 L of solution?
13. What distinguishes a weak acid from a strong acid?
14. What effect does increasing the pH of a solution have upon the
ionization of a carboxyl group? An amino group?
15. Name the four classes of organic molecules in the body.
16. Describe the three subclasses of carbohydrate molecules.
17. To which subclass of carbohydrates do each of the following
molecules belong: glucose, sucrose, and glycogen?
18. What properties are characteristic of lipids?
19. Describe the subclasses of lipids.
20. Describe the linkages between amino acids that form
21. What is the difference between a peptide and a protein?
22. What two factors determine the primary structure of a
23. Describe the types of interactions that determine the
conformation of a polypeptide chain.
24. Describe the structure of DNA and RNA.
25. Describe the characteristics of base pairings between
monounsaturated fatty acid
polar covalent bond
polyunsaturated fatty acid
ribonucleic acid (RNA)
saturated fatty acid
trans fatty acid
unsaturated fatty acid
van der Waals forces
sickle cell anemia
1. Describe the electrical charge, mass, and location of the three
major subatomic particles in an atom.
2. Which four kinds of atoms are most abundant in the body?
Chapter 2 Test Questions
(Answers appear in Appendix A.)
1. A molecule that loses an electron to a free radical
a. becomes more stable.
b. becomes electrically neutral.
c. becomes less reactive.
d. is permanently destroyed.
e. becomes a free radical itself.
2. Of the bonding forces between atoms and molecules, which are
a. hydrogen bonds
b. bonds between oppositely charged ionized groups
c. bonds between nearby nonpolar groups
d. covalent bonds
e. bonds between polar groups
3. The process by which monomers of organic molecules are made
into larger units
a. requires hydrolysis.
b. results in the generation of water molecules.
c. is irreversible.
d. occurs only with carbohydrates.
e. results in the production of ATP.
4. Which of the following is not found in DNA?
e. both b and d
5. Which of the following statements is incorrect about disulﬁ de
a. They form between two cysteine amino acids.
b. They are noncovalent.
c. They contribute to the tertiary structure of some proteins.
d. They contribute to the quaternary structure of some
e. They involve the loss of two hydrogen atoms.