Question

Imagine you have three test tubes containing identical solutions of purified, double-stranded human DNA. You expose the DNA in tube 1 to an agent that breaks the sugar-phosphate (phosphodiester) bonds. You expose the DNA in tube 2 to an agent that breaks the bonds that attach the bases to the sugars. You expose the DNA in tube 3 to an agent that breaks the hydrogen bonds. After treatment, how would the structures of the molecules in the three tubes differ?

Answer 1

DNA is the genetic material of all the living organism except some viruses. The structure of DNA consists of nitrogenous base, pentose sugar and the phosphate group.

Tube 1 - The nucleotide are linked together by phosphodiester bond. As these bonds are broken, the structure of DNA contains the individual complementary nucleotide are linked together by hydrogen bonds.

Tube 2 - The bond between the sugar and the bases are broken. The DNA structure consists of the phosphate group chain only with any pairing with the base.

Tube 3 - The DNA nitrogenous bases are adenine, guanine, thymine and cytosine that are linked together by hydrogen bonds. The agents break the hydrogen bonds. Now, the DNA structure consists of the single strand only.