Gene Expression and Regulation
What is termination in the process of translation?
The tRNA is ejected and the ribosome disassemble.
The mRNA is broken down
The ribosome is discarded and degraded
The polypeptide is freed from the ribosome
During elongation in eukaryotic translation, what would be affected if eEF2 were inhibited?
The translocation of tRNA from A-site to P-site on ribosome would be prevented.
Peptidyl transferase activity catalyzing peptide bond formation would diminish.
The binding affinity between mRNA and small ribosomal subunit would decrease.
The initiation complex formation at met-tRNA would be impaired.
Given cells expressing mutant eukaryotic release factors incapable of recognizing standard stop codons accurately during termination phase of translation, which cellular adaptation could potentially compensate for this deficiency?
Nonsense-mediated decay mechanisms become upregulated as a quality control response eliminating aberrant mRNAs before they accumulate toxic proteins
Enhanced activity peptidyl transferase enzyme promoting hydrolysis bond between final tRNA nascent peptide even absence conventional cues
Increased recruitment non-canonical release factors hat recognize these novel signals ensuring proper termination session cases where typical factors fail
Reduced efficiency RNA polymerase II transcription thereby decreasing production defective messenger RNAs carrying erroneous signal sequences
What molecule does a tRNA carry and add to the growing polypeptide chain during translation?
A sugar molecule.
A fatty acid.
A nucleotide.
An amino acid.
Which aspect of the elongation phase would be directly affected by a chemical that inhibits peptidyl transferase activity inside ribosomes?
Preventing recognition of correct anti-codons
Initiation complex including both small and large subunits
Breaking apart disassembly post-termination
Formation of peptide bonds between incoming adjacent molecules
Which of the following scenarios would most likely result in a functional protein despite the presence of a nonsense mutation early in the mRNA sequence?
A ribosome reads through the stop codon due to a tRNA with an altered anticodon that pairs with the stop codon.
An RNA polymerase attaches an incorrect nucleotide opposite the mutated base during transcription.
A chaperone protein assists in proper folding of the polypeptide chain past the point of mutation.
A spliceosome removes the exon containing the nonsense mutation during pre-mRNA processing.
In organisms where multiple copies of tRNA genes exist for each amino acid, what could be an evolutionary advantage when some but not all copies acquire mutations that prevent function?
All mutations in redundant tRNA genes are deleterious and reduce survivability by disrupting protein synthesis entirely.
Having multiple tRNA gene copies increases energy expenditure significantly due to unnecessary overproduction of these molecules.
Redundant tRNA genes allow for mutations without loss of function, possibly contributing to adaptability via neutral evolution.
Mutations across all copies can enhance translational accuracy and efficiency uniformly throughout populations immediately upon occurrence.

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Which of the following mutations in the coding sequence of a gene is most likely to have no effect on the amino acid sequence of the encoded protein?
A missense mutation that replaces one amino acid with another.
A nonsense mutation that creates a premature stop codon.
A frameshift mutation caused by nucleotide insertion.
A silent mutation that results in a synonymous codon.
How does a codon relate to an anticodon during translation?
It codes directly for a protein.
It pairs with its complementary anticodon on tRNA.
It transfers peptides.
It binds directly with an amino acid.
If a mutation occurs resulting in the insertion of an extra nucleotide pair, causing a frameshift, how will it affect the subsequent amino acid sequence?
Every following codon will be altered
The remaining sequence remains unchanged because of the redundancy of the genetic code
Only the immediately following codon will be altered
All stopping codons will now encode different amino acids