Chemical Composition of the Body
41
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-
dimensional shape?
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
water?
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
polypeptide chains.
21. What is the difference between a peptide and a protein?
22. What two factors determine the primary structure of a
polypeptide chain?
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
nucleotide bases.
molecule
20
monosaccharide
28
monounsaturated fatty acid
29
multimeric protein
35
mutation
35
neutral solution
26
neutron
19
nonpolar molecule
23
nucleic acid
35
nucleotide
36
pentose
28
peptide
33
peptide bond
31
pH
26
phospholipid
30
polar covalent bond
23
polar molecule
23
polymer
27
polypeptide
33
polysaccharide
28
polyunsaturated fatty acid
29
primary structure
33
protein
31
proton
19
purine
36
pyrimidine
36
quaternary structure
35
ribonucleic acid (RNA)
35
ribose
38
saturated fatty acid
29
secondary structure
34
solute
24
solution
24
solvent
24
steroid
31
strong acid
26
sucrose
28
tertiary structure
35
thymine
36
trace element
20
trans fatty acid
29
triglyceride
30
unsaturated fatty acid
29
uracil
38
van der Waals forces
34
weak acid
26
CLINICAL TERMS
sickle cell anemia
35
REVIEW QUESTIONS
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
strongest?
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?
a. adenine
b. uracil
c. cytosine
d. deoxyribose
e. both b and d
5. Which of the following statements is incorrect about disulfi de
bonds?
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
proteins.
e. They involve the loss of two hydrogen atoms.
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