Gene Expression Review 3 Flashcards
Peptide bond formation during translation is carried out by which subunit of the ribosome?
large
Thiostrepton inhibits EF-G. What part of the prokaryotic translation does it likely influence?
Ribosomal translocation
What is the major difference between prokaryotic and eukaryotic translation initiation?
Prokaryotic translation involves the joining of the mRNA and small ribosomal subunit before entry of the initiator tRNA. Eukaryotic translation involves joining of the initiator tRNA to the small subunit before mRNA joining.
What is the sequence of eukaryotic mRNA?
GCCACC
What kind of mutation results from and amino acid change?
missense
What kind of mutation results from the loss of two nucleotides?
frameshift
Which region in the figure above is bound by the poly (A) binding Protein (PABP)?
Region K (AAAAAAAAAA)
Between which two regions will a mutation most likely alter the protein sequence?
E and F (AUGC—//—AGGU—)
Which region in the figure is bound by elF4e?
Region J (7mG)
A mutation to which region in the figure above would disrupt recognition by the 18S rRNA of the small ribosomal subunit?
Region D (—GCCACC)
Which regions in the figure is most important for forming a closed-loop mRNA structure?
J and K (7mG and AAAAAAAA)
Which eukaryotic translation factor is required for a closed-loop mRNA structure found in the cytosol?
elF-4G
The genetic code is degenerate. Which of the following describes what they mean?
A given amino acid can be specified by more than one codon
Translation releasing factors (RF-1, RF-2, and Rf-3) are GTP-dependent proteins that enter into the A-site of the ribosomes when it is unoccupied due to a STOP codon. They promote hydrolysis of what?
The ester bond linking the polypeptide with the peptidyl site tRNA in the P-site
Which enzyme charges tRNA with the correct amino acid?
amino acyl tRNA synthetase
Which factor determines where translation initiates?
18s rRNA
Which factor recognizes UAA and UAG codons in mRNA?
RF-1
In which region of gene X in mutant strain #1 might there be a mutation which accounts for the large mRNA transcript?
branch point adenosine
Why is Protein X in mutant strain #1 smaller than Protein X in the wld type strain (despite having a larger mRNA)
The mutation of gene X n strain #1 results in fully processed transcript still containing an intron
In which region of gene X in mutant strain #2 might there be a mutation which accounts for a temperature sensitive Protein X?
exon
What type of mutation occurs in the gene encoding Protein X from mutant strain #2?
missense
In what kind of phospholipids, saturated or unsaturated, do you expect the level to be increased in a plasma membrane of bacteria that was moved from 37’C to 4’C?
unsaturated
What extracting agent would be used for extracting integral proteins from the membrane?
non-ionic detergent
What extracting agent would be used for extracting peripheral proteins from the membrane?
salt solution
What extracting agent would be used for extracting lipid-anchored proteins from the membrane?
phospholipase
