To determine the mRNA codons derived from the given DNA triplets TAC CAG, we first need to understand the process of transcription. During transcription, the DNA sequence is used as a template to create mRNA, where adenine (A) in DNA pairs with uracil (U) in RNA, and cytosine (C) and guanine (G) remain complementary.
Given the two DNA triplets:
- TAC
- CAG
We convert the first triplet:
- TAC → AUG (because T (thymine) in DNA pairs with A (adenine) in RNA, A goes to U, and C remains C)
For the second triplet:
- CAG → CUG (where C remains C, A goes to U, and G remains G)
So, the final sequence of mRNA codons for TAC CAG would be:
- AUG CUG
This means the correct choice is d. aug guc, which translates to methionine and leucine, the amino acids corresponding to those codons.