Question

Initiation codon in Protein synthesis is

• A. AUG
• B. UGA
• C. GUA
• D. UAG

Hint:

Easy Mnemonic: "Protein synthesis starts in AUGust." (AUG). Also, remember the stop codons: UAA, UAG, and UGA (University of Georgia).

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This is a basic molecular biology question regarding the genetic code and the process of translation (protein synthesis). It asks for the specific triplet of nucleotides that signals the start of a protein chain.
Detailed Explanation:

• Translation Process: Translation occurs in the ribosome, where mRNA is read to assemble amino acids. This process must start at a specific site to ensure the correct "reading frame."

• The Start Codon: In almost all organisms, the initiation codon is AUG. This codon has two functions: it signals the start of translation and it codes for the amino acid Methionine.

• Evaluation of Options:
• AUG: Initiation codon.

• UGA and UAG: Are "Stop Codons" (along with UAA) which signal the termination of protein synthesis.

• GUA: Codes for the amino acid Valine.

Step 2: Final Answer:
The initiation codon is AUG.