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3 votes
Which statement is FALSE?

a
Release factors bind to stop codons
b
Stop codons are recognized by a tRNA
c
The genetic code contains 3 stop codons (UAA, UAG, UGA)
d
ALL charged tRNAs (with the exception of the initiator tRNA) binds at the A site on the ribosome.

1 Answer

7 votes

Final answer:

The false statement is that stop codons are recognized by a tRNA; in reality, they are recognized by release factors during translation termination. The correct option is b.

Step-by-step explanation:

The false statement is: 'Stop codons are recognized by a tRNA'. In the process of translation termination, the stop codons (UAA, UAG, UGA) are recognized not by tRNA but by release factors. These release factors bind to the A site of the ribosome when a stop codon is encountered to end protein synthesis.

All other charged tRNAs, except for the initiator tRNA, indeed bind at the A site on the ribosome to add amino acids to the growing polypeptide chain; and the genetic code defines three stop codons which do not code for amino acids and signal the end of translation. Hence, b is the correct option.