Question

Step 5: Determine how treatment with hydroxyamine will alter each DNA stop codon and the resulting mRNA stop codon. In the last step, the DNA equivalent of each mRNA stop codon was determined. The mRNA and matching DNA stop codons are listed in the table. Also, recall from a previous step that hydroxylamine exposure results in the replacement of a C with a T and a G with an A. Determine how the reaction of DNA with hydroxylamine will alter each stop codon in the DNA and the mRNA. Place the DNA and mRNA stop codons after treatment with hydroxylamine under each of the original mRNA stop codons. The DNA stop codons also include the complementary strand of DNA. mRNA stop codon UAA UAG UGA ΤΑΑ ATT TAG ATC TGA ACT DNA stop codon Hydroxylamine treatment DNA after hydroxylamine mRNA after hydroxylamine ТАА ATT TGA ACT TAG ATC UAA UUA UAA

Answer 1

Hydroxylamine (NH2OH) is a hydroxylating agent. It causes only G:C to A:T transitions. When
DNA is treated with hydroxylamine, the amino group of cytosine is hydroxylated and form hydroxylaminocytosine base-pairs with adenine, leading to G:C to A:T transitions.

After treatment DNA stop codon is as follows

TAA/ATT

ACT/TAA

ATC/TAA

mRNA Stop codon will reamain UAA, UAG and UGA after treatment.