Aflatoxin B1 is a highly mutagenic and carcinogenic compound produced by certain fungi that infect crops such as peanuts. Aflatoxin is a large, bulky molecule that chemically bonds to the base guanine...

1. Aflatoxin B1 is a highly mutagenic and carcinogenic compound produced by certain fungi that infect crops such as peanuts. Aflatoxin is a large, bulky molecule that chemically bonds to the base guanine (G) to form the aflatoxin-guanine adduct that is pictured below. In the figure below, the aflatoxin is orange, and the guanine base is purple. This adduct distorts the DNA double helix and blocks replication.

a. What type(s) of DNA repair system is (are) most likely to be involved in repairing the damage caused by exposure of DNA to aflatoxin B1?

b, Recent evidence suggests that the adduct of guanine and aflatoxin B1 can attack the bond that connects it to deoxyribose; this liberates the adducted base, forming an apurinic site. How does this new information change your answer to part (a)?