Lecture 4 - Transcription & Translation Flashcards
Which type of RNA accounts for the majority of total cellular RNA and functions to catalyze protein synthesis?
rRNAs
Which type of RNA is a component of the splicesome during RNA splicing?
snRNAs
The RNA is complementary to the template strand and therefore has the same 5’ –> 3’ base sequence as the ________ strand.
Non-template
The template strand is also called the _____ strand.
Antisense strand
The sequence of transcribed RNA is normally identical to that of the _____ strand, except that U replaces T.
sense strand (non-template strand)
Three different types of ________ are present in the nucleus of human cells.
RNA polymerases
Which type of RNA Polymerase synthesizes 28s, 18s, and 5.8s rRNAs?
RNA Polymerase I
Which type of RNA Polymerase synthesizes mRNA (and some miRNAs and snRNAs)?
RNA Polymerase II
At what portion of the promoter sequence does RNA polymerase bind and initiate RNA synthesis?
Initiator (Inr) sequence
An important promoter sequence consists of the _________ located approximately 30 bp upstream of the transcription initiation site of many (but not all!) genes.
TATA box
What (enzyme) initiates transcription of a eukaryotic gene?
RNA Polymerase II
At many promotors, transcription is initiated at the TATA box, which is recognized and bound by ______.
Transcription factor TFIID
The “cap” is added to the 5’ end of mRNA by guanylyl transferase through what type of bond?
5’-5’ phosphodiester bond
Which sequence (added during RNA processing) is important for mRNA stability, NUCLEAR EXPORT, and translation?
poly A sequence
Which sequence (added during RNA processing) is important for mRNA PROTECTION, SPLICING, stability, and translation?
“cap” on hnRNA
The capping and poly A addition to the hnRNA is followed by RNA splicing that results in the removal of introns and joining of the exon sequences. What catalyzes this process and where does it occur?
snRNPs catalyze the process in the spliceosome
Duchenne’s muscular dystrophy and Beta-Thalassemia are caused by?
Mutations in the splice site
The degeneracy of the genetic code most often involves the:
third base of the codon
The specific “anticodons” of transfer RNAs are ______ and _______ to an mRNA codon?
complementary and anti-parallel
For the mRNA initiator methionine codon 5’-AUG-3’, the tRNA anticodon would be:
3’-UAC-5’
Many tRNAs can recognize more than one codon due to __________ between the third position of the codon in mRNAs and the first position of the anticodon in the rRNAs.
wobble base pairing
Where does wobble base pairing occur?
Between the third position of the codon in mRNAs and the first position of the anticodon in the rRNAs
What is the site of protein synthesis?
the ribosome
__________ attach amino acids through their carboxyl groups to the CCA sequence at the 3’ end of tRNAs.
Aminoacyl-tRNA synthetases
The energy realized in the attachment of amino acids to tRNAs is used subsequently for the formation of the:
peptide bond
Two adaptors act one after another to translate the genetic code. What are they?
- Aminoacyl-tRNA synthetase
2. tRNA molecule itself
The association of what two specific structures occurs AFTER the initiation complex scans the mRNA (until the first AUG codon is found) but PRECEDES initiation of protein synthesis?
- 60S ribosomal subunit
2. 80S initiation complex
The ribozyme (peptidyl transferase) catalyzes the formation of _____ between the carboxyl group of one amino acid and the amino group of the next incoming amino acid.
peptide bond
After the action of ______ the ribosome dissociates into its two separate subunits.
Ribosome recycling factor
What are three termination codons?
UAA, UAG, UGA
Which of the following statements about tRNA is TRUE:
a) It converts DNA into protein
b) It contains specific anticodons of three bases
c) It contains specific codons of three bases
d) It recognizes stop codons to terminate transcription
B. tRNA contains specific anticodons of three bases.
tRNA translates amino acids until the binding of a release factor to an A-site bearing a stop codon terminates translation.
A patient has ingested mushrooms containing a toxin that has been found to specifically inhibit messenger RNA (mRNA) production. The toxin is most likely to directly inhibit:
A. DNA polymerase B. Reverse transcriptase C. RNA polymerase I D. RNA polymerase II E. RNA polymerase III
D.
