02.14 - Translation Flashcards
Which of the following is not needed in translation?
a. Promoter sequence
b. Translation factors
c. Energy sources
d. Enzymes
a. Promoter sequence
In which part of the tRNA is the amino acid attached?
Acceptor arm/3’ end
Which part of the tRNA contains the recognition site for specific aminoacyl-tRNA synthetase?
D arm
Which part of the tRNA binds aminoacyl-tRNA to ribosomal subunit?
Thymidine-Pseudouridine-Cystidine Arm
True or False: The binding of specific amino acids with their corresponding tRNAs requires ATP.
True
Which part of the amino acid binds to the 3’ end of the tRNA?
Carboxyl end
This process involves the conversion of RNA into a protein product.
Translation
When multiple codons can code for the same amino acid, translation is said to be __________.
Degenerate
When a particular codon can code only for a single amino acid, it is said to be ___________.
Unambiguous
Which of the following is not a characteristic of the genetic code in translation?
a. Overlapping
b. Unpunctuated
c. Universal
d. None of the above
a. Overlapping (There is no overlap in reading codons.)
Which is the first step in the initiation phase of translation?
Dissociation of ribosomes into 40S and 60S subunits
Which initiation factors stabilises the dissociated ribosomal subunits?
eIF-3 and eIF-1A
What initiation factor binds to GTP to form a complex that binds to methionyl-tRNA?
eIF-2
The eIF-2-GTP-Met-tRNA complex binds to which ribosomal subunit to form the 43S pre initiation complex?
40S subunit
What forms when mRNA binds to the 43S pre-initiation complex?
48S initiation complex
What initiation factor complex is responsible for the binding and removal of the mRNA 5’ methyl cap?
eIF-4F complex
What specific initiation factor serves as a scaffolding protein that holds other initiation factors of the eIF-4F complex?
eIF-4G
Which initiation factor is responsible for recognising and binding to the methyl cap?
eIF-4E
What inhibits initiation when bound to eIF-4E?
BP-1
What triggers the detachment of BP-1 from eIF-4E?
Phosphorylation by insulin and mitogens
What initiation factors removes the 5’ methyl cap from the rest of the mRNA?
eIF-4A and eIF-4B
What is the prokaryotic counterpart of the eukaryotic 5’ cap?
Shine-Dalgarno sequence
This consensus sequence covers purines from -3 to +4 around the AUG sequence, and is scanned by the 48S initiation complex.
Kozak sequence
Binding of the 48S initiation complex into the 60S subunit forms _____________.
80S initiation complex
Which initiation factor hydrolyses the GTP bound to eIF-2 to remove all initiation factors from the complex?
eIF-5
Which is not part of the 80S initiation complex
a. 40S and 60S subunits
b. mRNA without methyl cap
c. Initiation factors
d. Met-tRNA
c. Initiation factors
What phase follows the initiation phase of translation?
Elongation
What elongation factor binds to GTP, forming a complex that bdins with the entering aminoacyl-tRNA?
eEF-1alpha
Which of the following statements is incorrect?
a. The amino group of A site aminoacyl-tRNA will make a nucleophilic attack on the carbonyl group of the P site aminoacyl tRNA.
b. Peptide bond formation is catalysed by peptidyltransferase.
c. Peptidyltransferase is a component of the 40S subunit.
d. None of the above.
c. Peptidyltransferase is a component of the 40S subunit. (It is a component of the 60S subunit.)
What elongation complex facilitates the transfer of A-site tRNA to the P site?
eEF-2 + GTP
How many ATPs are consumed in the activation of tRNA?
2 ATPs
How many GTPs are consumed in the entry of aminoacyl-tRNA into the A site?
1 GTP
How many GTPs are consumed in the translocation of mRNA along the ribosome?
1 GTP
How many ATPs and GTPs are consumed in the initiation phase?
1 ATP (ATP hydrolysis facilitates mRNA binding to 43S complex) 1 GTP (GTP binds to eIF-2, which is then hydrolysed by eIF-5 for the release of initiation factors)
A hypothetical polypeptide chain is composed of Met-Val. How many ATPs and GTPs are consumed in the overall translation process?
1 ATP + 1 GTP (initiation)
2 ATP + 1 GTP + 1 GTP (elongation)
1 GTP (termination)
= 3 ATPs and 4 GTPs
What removes the polypeptide chain from the P-site tRNA?
eRFs + GTP + peptidyltransferase
What reaction is facilitated by the eRF-GTP-peptidyltransferase complex?
Hydrolysis
What release factor responds to UAA and UAG stop codons?
eRF-1
What release factor responds to UAA and UGA stop codons?
eRF-2
What release factor binds to GTP?
eRF-3
