29 Questions
What is required to be removed before degradation of eukaryotic mRNA can proceed?
Poly (A) tail
Which enzyme is responsible for removing the cap during degradation of eukaryotic mRNA?
Decapping protein (Dcp1)
What determines the stability of eukaryotic mRNA?
Destabilizing sequences
Which subunit binds to the messenger RNA during translation?
30S subunit
What initiates the coding sequence in eukaryotic mRNA translation?
Start codon
What are the three major types of processing that RNA molecules undergo?
Base modification, cleavage, splicing
Which of the following statements about eukaryotic mRNA processing is TRUE?
Eukaryotic mRNA contains a cap and tail, and undergoes base modification
What is the main function of non-coding RNA?
To perform active roles other than encoding proteins
Which process involves the addition of a cap and tail to eukaryotic mRNA?
Translation
What type of RNAs are used not to carry information but to perform active roles?
non-coding RNAs
Which statement is FALSE regarding RNA processing?
RNA undergoes capping and tailing but not splicing
What is the role of the Poly(A) tail in eukaryotic mRNA?
Adds stability and protection to the mRNA
What is the function of cleavage stimulation factor (CST) in eukaryotic mRNA processing?
Binds to GU-rich tract
What happens to prokaryotic mRNA when a poly(A) tail is added?
Triggers mRNA degradation
What is the function of the spliceosome in mRNA processing?
Joins exons together after intron removal
Which component forms a small nuclear ribonucleoprotein (snRNP) in the spliceosome?
Small nuclear RNA (snRNA)
What is the main difference between the poly(A) tail function in eukaryotes and prokaryotes?
Adds stability in eukaryotes, promotes degradation in prokaryotes
What is the role of initiation factor 3 (IF-3) during translation initiation?
It prevents the large ribosomal subunit from binding during initiation.
Which molecule pairs with its complementary nucleotides in the 16S rRNA during translation initiation?
Shine-Dalgarno sequence
In eukaryotic cells, what plays a critical role similar to Shine-Dalgarno sequence in bacterial translation initiation?
Cap at the 5' end of mRNA
What is the function of elongation factor G (EF-G) in translation elongation?
Allows the ribosome to translocate down mRNA
Why does protein synthesis terminate when a termination codon is encountered?
Release factors cause the dissociation of ribosomal subunits.
What happens during translocation in translation elongation?
The ribosome moves down mRNA in the 5'—3' direction.
What are the three release factors in E. coli that form a complex with GTP and bind to the ribosome?
RF1, RF2, and RF3
Which release factor recognizes the termination codons UGA and UAA in E. coli?
RF1
In eukaryotic cells, what is the function of eRF2?
Binds GTP and stimulates the release of the polypeptide from the ribosome
What feature distinguishes the termination process in eukaryotic cells from prokaryotic cells?
Eukaryotic release factor eRF1 recognizes all three termination codons, unlike in prokaryotic cells
What can affect the initiation of translation according to the text?
The availability of ribosomes, tRNAs, initiation and elongation factors
How do posttranslational modifications affect eukaryotic proteins?
They affect the transport, function, and activity of proteins
This quiz covers the processing of RNA, including different ways RNA is processed, the presence of a cap and tail in eukaryotic messenger RNA, removal of introns by splicing, and mRNA degradation. It also explores the process of translation, including initiation and termination steps.
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