What sequence on the template strand of DNA corresponds to the first amino acid inseed into a protein?
**Core Concept**
The question tests understanding of the **central dogma** of molecular biology, specifically **transcription** and **translation**. It requires knowledge of how **nucleotide sequences** on the **template strand** of DNA are transcribed into **mRNA** and then translated into **amino acids**.
**Why the Correct Answer is Right**
The first amino acid incorporated into a protein is typically **methionine**, which is encoded by the **AUG** codon on mRNA. Since mRNA is complementary to the template strand of DNA, and considering the **5' to 3'** direction of transcription, the sequence on the template strand that corresponds to the AUG codon on mRNA would be **TAC** in the **3' to 5'** direction, but since the question seems incomplete regarding the options, the general principle is that the **anticodon** on tRNA that recognizes the **AUG** start codon on mRNA is **UAC**. However, the sequence on the DNA template strand corresponding to the first amino acid (methionine) would indeed be complementary to the mRNA sequence **AUG**, which is **TAC** on the template strand.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific sequences provided in the question, we cannot directly address why each option is incorrect based on their content. Normally, we'd compare each option against the known sequence **TAC** or the process of transcription and translation to identify the correct sequence that would code for methionine.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **AUG** is the start codon for **methionine**, and all proteins begin synthesis with this amino acid. Understanding the genetic code and how it translates into amino acid sequences is crucial for comprehending protein synthesis and its regulation.
**Correct Answer:** Correct Answer: D. TAC