Question

DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?

Answer 1

DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?

A) The purines would be separated from the deoxyribose sugars.

B) The pyrimidines would be separated from the deoxyribose sugars.

C) All bases would be separated from the deoxyribose sugars.

D) The two strands of the double helix would separate.

E) The phosphodiester bonds between deoxyribose sugars would be broken.

Answer:

E) The phosphodiester bonds between deoxyribose sugars would be broken.

Explanation:

The purines and pyrimidines of two DNA strands of a DNA duplex are held together by hydrogen bonds. Hydrogen bonds are not covalent bonds. The enzyme DNAase targets the phosphodiester bonds. These are the covalent bonds that join two deoxyribonucleotides of a DNA strand together. therefore, when a DNA is subjected to digestion with DNAase enzyme, the phosphodiester bonds will be broken that hold the pentose sugars of two nucleotides by a phosphate group.