Question

The codon for anticodon 3’ UUA 5’ is
(A) 5’ AAU 3’
(B) 3’ AAU 5’
(C) 5’ AAT 3’
(D) 3’ AAG 5’

Answer 1

Hint: An anticodon is a trinucleotide sequence complementary to that of a corresponding codon in a messenger RNA (mRNA) sequence. An anticodon is present at one end of a transfer RNA (tRNA) molecule. During the protein synthesis process, each time an amino acid is added to the growing protein, a tRNA forms base pairs with its complementary sequence on the mRNA molecule.

Complete answer:
The transfer of RNA has an anticodon loop with a three-base sequence that base-pairs with mRNA codons. The mRNA codon is read in 5' to 3 directions and the first base of the codon in mRNA pairs with the third base of the anticodon. The codon and anticodon are never read in the same direction; an anticodon with 3' UUA 5' cannot have a codon with 3' UUA 5'.

Additional Information: -The start codon is AUG, methionine is the only amino acid which is specified by just one codon, AUG.
-The stop codons are UAA, UAG, and UGA. They encode no amino acid. The ribosome pauses and falls off the mRNA.
-The stretch of codons between the start codon and a stop codon is called an open reading frame (ORF).
-Other amino acids are specified by more than one codon-usually differing at only the third position.
So, the correct answer is 5’ AAU 3’.

Note: Translation involves the conversion of a four-base code (ATCG) into twenty different amino acids. A codon specifies a given amino acid. The conversion of codon information into proteins is conducted through transfer RNA. Each of the transfer RNA (tRNA) has an anticodon that can pair with a codon. Some of the anti-codons have modified bases that can pair with more than one codon, specifying the same amino acid which means that we don't need 61 different tRNA molecules for all 61 codons.