Question

Majority of the tRNA molecules have the following sequence at their 3'-end:

• A. CCA-3'-OH
• B. CGA-3'-OH
• C. GGA-3'-OH
• D. AAA-3'-OH

Hint:

tRNA 3' end: Always CCA-3'-OH.
The amino acid is attached to the terminal A (aminoacyl-tRNA).
CCA addition is post-transcriptional.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
tRNA (transfer RNA) is a key molecule in protein synthesis.
It carries amino acids to the ribosome during translation.

Step 2: Detailed Explanation:
All tRNAs have the sequence CCA at their 3' end.
The terminal adenosine (A) is the site where the amino acid is attached (aminoacyl-tRNA).
The 3'-OH group forms an ester bond with the carboxyl group of the amino acid.
Thus, the sequence at the 3' end is CCA-3'-OH.
Other options (CGA, GGA, AAA) are not standard tRNA termini.

Step 3: Final Answer:
Thus, the majority of tRNA molecules have CCA-3'-OH at their 3'-end, which corresponds to option (A).
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