Question

Given the codon 5'CAU3', what is the DNA sequence that complements this codon?

a. 3'CAU5'
b. 3'GTA5'
c. 3'GTT5'
d. 3'GUA5'
e. 3'GUT5'

Answer 1

The complementary DNA sequence to the mRNA codon 5'CAU3' is 3'GTA5', which is answer choice b.

Step-by-step explanation:

The codon 5'CAU3' is part of a messenger RNA (mRNA) sequence. The complementary DNA sequence to the mRNA codon 5'CAU3' would be the sequence that can pair with the RNA codon during the process of transcription. This means you will have to find the DNA sequence that can form the correct base pairs with this RNA sequence. Since in RNA, adenine (A) pairs with uracil (U), but in DNA, adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C), the DNA complement to CAU would be GTA, considering the standard base pairing. Therefore, the correct complementary DNA sequence to the mRNA codon 5'CAU3' is 3'GTA5', which is answer choice b.