11. Determine what is the most common mechanism for repairing damage to DNA?
a. direct repair of the damage
b. selective excision of the damaged section and use of the complementary strand to replace
excised portion
c. simple removal of damaged portion without replacement
d. simplistic repair of the damage
e. altruistic repair of the damage

12. Individuals with xeroderma pigmentosum inherit a faulty DNA repair mechanism. As a consequence, they
a. are sterile.
b. have no proofreading during DNA replication.
c. cannot join the Okazaki fragments produced during DNA replication.
d. easily develop skin cancer when exposed to sunlight.

13. Which of the following reasons explains why a single-stranded DNA circle cannot serve as a DNA
polymerase template?
a. DNA polymerase cannot initiate DNA strand formation.
b. DNA polymerase can only add nucleotides to the 3'-hydroxyl end of an existing strand.
c. DNA polymerase can only add nucleotides to the 5'-hydroxyl end of an existing strand.
d. DNA polymerase requires a primer.
e. a, b and d

14. The 3' end of most eukaryotic mRNAs contains a ______, while the 5' end has a _________.
a. poly(A) tail, methylated guanosine cap
b. poly(U) tail, methylated guanosine cap
c. methylated guanosine cap, poly(A) tail
d. poly(A) tail, sulfonated guanosine cap
e. methylated guanosine cap, poly(U) tail

15. The greatest similarities among codons specifying the same amino acid occur _________.
a. in the first two nucleotides of the triplet
b. in the last two nucleotides of the triplet
c. in the first and third nucleotides of the triplet
d. in the third nucleotide of the triplet
e. in the middle nucleotide of the triplet

16. The clustering of codons in the genetic code provides what advantage to living organisms?
a. Clustering assures that all amino acids are different.
b. Clustering ensures that a single base change will often replace a hydrophobic amino acid with
another hydrophobic amino acid.
c. A single base change will often not change the amino acid that is to be inserted into the growing
polypeptides.
d. Clustering increases the lifespan of the organism.
e. b and c