The compound known as nitrous acid is a reactive chemical that replaces amino groups (-NH2) with keto groups (=O). When nitrous acid reacts with the bases in DNA, it can change cytosine to uracil and change adenine to hypoxanthine. A DNA double helix has the following sequence:
5' - TTGGATGCTGG - 3'
3' - AACCTACGACC - 5'
A) What would be the sequence of this double helix immediately after reaction with nitrous acid? Let the letter H represent hypoxanthine and U represent uracil.
a) 5' - TTGGATGCTGG - 3'
3' - AACCTACGACC - 5'
b) 5' - TTGGATGUTHH - 3'
3' - AACCTACGACC - 5'
c) 5' - TTGGATGCTGG - 3'
3' - AACHHTACGACC - 5'
d) 5' - TTGGATGCTGG - 3'
3' - AUUCCTACGACC - 5'