Multiple Choice
In the context of translation, which organelle is primarily responsible for synthesizing proteins?
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5. DNA to RNA to Protein
Translation
Multiple Choice
In eukaryotic translation, what occurs when the ribosome reaches a stop codon (UAA, UAG, or UGA) in the A site?
A
The ribosome shifts reading frames by one nucleotide to bypass the stop codon and continue elongation.
B
A specialized tRNA carrying methionine binds to the stop codon and adds a final amino acid to terminate translation.
C
The large ribosomal subunit alone catalyzes formation of a new peptide bond at the stop codon to cap the polypeptide.
D
A release factor binds in the A site and stimulates hydrolysis of the peptidyl-tRNA bond, releasing the completed polypeptide and leading to ribosome dissociation.
Verified step by step guidance1
Understand that during eukaryotic translation, the ribosome reads mRNA codons sequentially in the A site to add amino acids to the growing polypeptide chain.
Recognize that stop codons (UAA, UAG, UGA) do not code for any amino acid and signal termination of translation rather than elongation.
Know that when a stop codon enters the A site, no tRNA with a complementary anticodon binds; instead, a protein called a release factor binds to the A site.
The release factor catalyzes the hydrolysis of the bond between the polypeptide chain and the tRNA in the P site, freeing the completed polypeptide.
Following polypeptide release, the ribosomal subunits dissociate from the mRNA, effectively ending the translation process.
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