Question

Which one of the following is the starter codon ?

• A. UGA
• B. UAA
• C. UAG
• D. AUG

Answer 1

The Correct Option is D

The question is about identifying the starter codon among the given options. In the genetic code, a starter, or start codon, is a specific sequence of nucleotides that signals the initiation of protein synthesis on mRNA strands.

Let's evaluate each option to determine which is the start codon:

1. UGA: This is a stop codon. It signals the termination of protein synthesis. Therefore, it is not the starter codon.
2. UAA: This is also a stop codon, functioning similarly to UGA by terminating protein synthesis. Hence, it is not the start codon.
3. UAG: Like UGA and UAA, UAG is a stop codon and not a start codon.
4. AUG: This is the start codon in most organisms. It codes for the amino acid methionine and signals the start of translation.

Hence, the correct answer is AUG as it serves as the initiation signal for ribosomes to begin translating mRNA into a protein.