Question

If the base sequence of a codon in mRNA is 5'- AUG - 3', the sequence of tRNA pairing with it must be:

• A. 5 '- GUA - 3'
• B. 5' - UAC - 3'
• C. 5' - AUG - 3'
• D. 5' - CAU - 3'

Answer 1

The correct option is D 5' - CAU - 3'

Anticodon:

tRNA has an anticodon loop. The bases in this anticodon loop form hydrogen bonds with the codons on mRNA. Anticodons are complementary to the codons on the mRNA.




Anticodon sequence:

If the mRNA codon is 5' - AUG - 3', then the tRNA anticodon will be 3’ - UAC - 5’. The base sequences are usually read in the $5^{\prime }\to \to 3^{\prime }$ direction. Therefore, the codon of tRNA anticodon in the $5^{\prime }\to 3^{\prime }$ direction is 5’- CAU - 3’.

Hence option b is correct.


Final answer: b. 5 '- CAU - 3'