Translation – initiation, elongation, termination, proofreading, post-translational modifications - One Line Questions
1.
What structure allows the ribosome to move along the mRNA molecule during elongation? —
Translocation
2.
Which process involves the removal of specific amino acid sequences from a polypeptide chain? —
Proteolytic cleavage
3.
Phosphorylation is the addition of a phosphate group, often to which amino acid residues? —
Serine, Threonine, Tyrosine
4.
Which of the following is a common mechanism for post-translational control of protein activity? —
Reversible phosphorylation
5.
Which codons are recognized as stop codons in most genetic codes? —
UAA, UAG, UGA
6.
What event signals the termination of translation? —
Binding of a release factor to a stop codon
7.
Post-translational modification can occur in various cellular compartments. Where does N-linked glycosylation primarily occur? —
Endoplasmic reticulum and Golgi apparatus
8.
A protein that is destined for secretion or insertion into the plasma membrane typically enters which pathway after synthesis begins? —
Endoplasmic reticulum
9.
Which enzyme is responsible for attaching the correct amino acid to its corresponding tRNA? —
Aminoacyl-tRNA synthetase
10.
Which initiation factor in eukaryotes is responsible for binding the initiator tRNA to the 40S subunit? —
eIF2
11.
Which component is essential for the eukaryotic translation initiation factor (eIF4F) complex to bind to the mRNA 5' cap? —
eIF4E
12.
Which type of modification involves the addition of a methyl group, for example, to arginine and lysine residues? —
Methylation
13.
The process of adding a phosphate group to a protein is known as: —
Phosphorylation
14.
Which of the following is a critical component of the ternary complex that delivers aminoacyl-tRNA to the ribosome during elongation? —
GTP
15.
Which type of bond is formed between amino acids during translation? —
Peptide bond
16.
Which of the following is a key event in translation termination? —
Binding of a release factor to the A site
17.
Which post-translational modification involves the addition of a lipid group to a protein? —
Lipidation
18.
Which molecule binds to the stop codon on the mRNA and leads to the termination of translation? —
Release factor
19.
In prokaryotes, the initiation complex includes: —
Initiator tRNA, mRNA, 30S ribosomal subunit, initiation factors
20.
What is the significance of the anticodon loop on a tRNA molecule? —
It recognizes and binds to the complementary codon on the mRNA.
21.
What is the role of the initiator tRNA during translation initiation in eukaryotes? —
It carries methionine and recognizes the start codon AUG
22.
What is the function of the Shine-Dalgarno sequence in prokaryotic mRNA? —
It is recognized by the small ribosomal subunit to initiate translation.
23.
The process where a protein folds into its correct three-dimensional structure is crucial for its function and can be aided by: —
Chaperones
24.
Which modification involves the addition of an acetyl group, often to lysine residues on histone proteins? —
Acetylation
25.
The movement of the ribosome one codon down the mRNA during elongation is called: —
Translocation
26.
Which of the following is NOT a typical post-translational modification? —
DNA replication
27.
The process of adding a sugar molecule to a protein is called: —
Glycosylation
28.
Which of the following is a form of post-translational modification that marks proteins for degradation? —
Ubiquitination
29.
In prokaryotes, translation initiation typically begins with the binding of the ribosome to which sequence on the mRNA? —
Shine-Dalgarno sequence
30.
What is the primary difference in initiation between prokaryotic and eukaryotic translation? —
Prokaryotes initiate internally, eukaryotes initiate at the 5' cap.
31.
The formation of a peptide bond between amino acids is catalyzed by which component of the ribosome? —
rRNA (ribozyme activity)
32.
Which of the following is a common post-translational modification that can regulate protein activity? —
Acetylation
33.
Which subunit of the ribosome is primarily responsible for binding mRNA? —
The 30S subunit (prokaryotes)
34.
Eukaryotic translation initiation requires the assembly of the 80S ribosome on mRNA. Which subunit initially binds to the mRNA cap? —
The 40S subunit
35.
What is glycosylation? —
The addition of a sugar moiety to a protein
36.
What happens at the P site of the ribosome during elongation? —
The tRNA holding the growing polypeptide chain is located
37.
During elongation, where does the incoming aminoacyl-tRNA bind? —
The A site (Aminoacyl site)
38.
What is the role of ubiquitination in post-translational modification? —
To signal for protein degradation
39.
What is the role of elongation factors (e.g., EF-Tu in bacteria, eEF1A in eukaryotes) during translation? —
To facilitate the binding of aminoacyl-tRNAs to the A site
40.
What is the function of the E site on the ribosome? —
To release the deacylated tRNA
41.
What is the primary role of initiation factors in translation? —
To bind the initiator tRNA and assemble the ribosomal subunits on the mRNA
42.
What is the purpose of proofreading mechanisms during translation? —
To ensure the correct amino acid is added to the growing polypeptide chain
43.
What is the function of the A site on the ribosome during elongation? —
To bind the incoming aminoacyl-tRNA carrying the next amino acid
44.
What is the role of the signal recognition particle (SRP) in translation? —
To target proteins with signal sequences to the endoplasmic reticulum
45.
What is the function of peptidyl transferase activity within the ribosome? —
To catalyze the formation of a peptide bond between the amino acid on the A-site tRNA and the growing polypeptide chain
46.
What is the function of release factors during translation termination? —
To hydrolyze the polypeptide chain from the last tRNA
47.
What is the primary role of chaperones in protein synthesis? —
To assist in proper protein folding
48.
What is the role of aminoacyl-tRNA synthetases in translation? —
To charge tRNAs with the correct amino acids
49.
What is the primary function of ribosomes during translation? —
To catalyze the formation of peptide bonds between amino acids
50.
Which molecule carries the genetic code from the nucleus to the ribosome? —
Messenger RNA (mRNA)