Question

what would be the dna code for an mrna strand that reads, \uau\?

Explanation:

Step1: Recall base - pairing rules

In DNA - mRNA transcription, A (adenine) pairs with U (uracil) in mRNA, T (thymine) pairs with A (adenine), G (guanine) pairs with C (cytosine), and C pairs with G. But for the DNA code corresponding to mRNA, we consider the non - coding strand (template strand). The mRNA is synthesized from the DNA template strand. The base - pairing rules for DNA (template) to mRNA are: DNA (T) pairs with mRNA (A), DNA (A) pairs with mRNA (U), DNA (G) pairs with mRNA (C), DNA (C) pairs with mRNA (G).
If the mRNA is "UAU", then working backwards:
For the first base 'U' in mRNA: In DNA, it is paired with 'A'
For the second base 'A' in mRNA: In DNA, it is paired with 'T'
For the third base 'U' in mRNA: In DNA, it is paired with 'A'

Answer:

ATA