30 Questions
Which direction does translation proceed in?
From the amino to the carboxyl terminus
What is the start codon for all protein synthesis?
AUG
What do specific stop codons signal during translation?
The end of translation
What is the process called when specific amino acid side chains are modified after translation?
Posttranslational modification
What is the enzyme responsible for covalently linking amino acids to tRNA?
Aminoacyl-tRNA synthetase
What is the process called when proteins are marked for degradation?
Ubiquitination
Which molecule carries the appropriate amino acid to the site of synthesis on the ribosomal complex?
tRNA
What is the function of aminoacyl-tRNA synthetases?
To catalyze the attachment of amino acids to tRNA
What molecule carries the code in triplicate?
mRNA
What are the components required for translation?
Amino acids, tRNA, mRNA, rRNA, protein factors
How many codons code for termination/stop codons?
Three
What is the consequence of altering the nucleotide sequence in the coding region of mRNA?
All of the above
Which family of enzymes is required for attaching amino acids to tRNA?
Aminoacyl-tRNA synthetases
What is the function of the editing activity of aminoacyl-tRNA synthetases?
To remove incorrect amino acids from the enzyme or tRNA
What is the cellular location of free ribosomes in eukaryotes?
Cytosol
What is the role of initiation factors in translation?
All of the above
What is the mechanism by which tRNA recognizes more than one codon for a specific amino acid?
Wobble hypothesis
Which initiation mechanism is used by eukaryotes to recognize the start codon?
5'-cap
Which codon on mRNA signals the start of protein synthesis and codes for methionine?
AUG
Which of the following codons on mRNA signals the end of protein synthesis and does not code for an amino acid?
UAA
What is the role of the Shine-Dalgarno sequence in translation initiation in prokaryotes?
It aids in translation initiation.
What is the role of the mRNA cap and poly-A tail in translation initiation in eukaryotes?
They aid in translation initiation.
Which protein factors are involved in the initiation, elongation, and termination of protein translation?
RF 1/2 (prok) and eRF (euk)
How do frameshift, missense, and nonsense gene mutations alter the reading frame of the mRNA and the protein synthesized from it?
They alter the reading frame and the protein.
Which of the following is true about the initiation codon?
The initiation codon is recognized by tRNAi
What distinguishes tRNAi from internal AUG-tRNA?
tRNAi goes directly to P-site
What does bacterial tRNAi carry?
Bacterial tRNAi carries N-formylated methionine (fMet)
What prevents the premature binding of the large subunit during initiation?
IF-3 (prok) and eIF-3 (euk)
What is the role of EF-Tu-GTP in elongation?
EF-Tu-GTP facilitates delivery of charged tRNA for the next mRNA codon located in the A-site
What determines how a protein will fold?
Primary linear amino acid sequence
Test your knowledge on aminoacyl-tRNA synthetases and their role in protein translation. Explore their mechanism, specificity, and editing activity in this quiz.
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