The base analog 2-amino purine (2-AP) substitutes for adenine during DNA replication, but it 
may base-pair with cytosine. The base analog 5-bromouracil (5-BU) substitutes for thymidine, 
but it may base-pair with guanine. Follow the double-stranded trinucleotide sequence shown 
here through three rounds of replication, assuming that, in the first round, both analogs are 
present and become incorporated wherever possible. Before the second and third round of 
replication, any unincorporated base analogs are removed. What final sequences occur?

After mutagen treatment, a molecule of 2-aminopurine (an adenine analogue) incorporates into DNA. During replication the 2-AP protonates. When 2-AP protonates it pairs with cytosine. What will the mutational event caused by this be? Write your answer in the form of XX→XX (for example, AT→TA):

The rare enol form of thymine pairs with guanine. If a thymine enolization occurs during replication in an AT pair, what will be the resulting mutant pair?

A) Briefly describe how base analogs and ionizing radiation cause mutations in DNA. Also state what class of mutation – point, insertion/deletion (indel), chromosomal – will be created for each one.

B) Give an example of a base analog, and of ionizing radiation.

C) Nitrous acid (NA) deaminates adenine to form hypoxanthine, which forms two hydrogen bonds with cytosine during DNA replication. After a wild type strain of bacteria is treated with NA, a mutant is recovered that is caused by an amino acid substitution in a protein: wild type Met has been replaced with Val in the mutant. What is the simplest explanation for this observation?

Which of the following mutagens would be MOST likely to revert(cause a reversion of) a mutation that resulted from a single base(pair) deletion?

a. aphlatoxin V 1 (a potent carcinogen that attaches to "G")

b. 5-bromouracil (a base analogue)

c. 2-amino purine (a base analogue)

d. proflavin (an intercalating agent)

e. MMS (methyl metane sulfonate, an alkylating agent)