M11 Flashcards
Functions of RNA polymerase include:
searching for promoter sites, unwinding short stretches of DNA, detecting termination signals
For transcription to occur, the structure of DNA must be in
the open promoter complex.
The Pribnow box
is the site where RNA polymerase binds.
The protein that binds DNA sequences and helps RNA polymerases initiate transcription is:
σ
What RNA sequences are spliced out of mature eukaryotic mRNA molecules?
Introns
The processivity of transcribing RNA polymerase is approximately
essentially infinite
The proteins that bind DNA at eukaryotic promoters to form the initiation complex are called
transcription factors
Which of the following modifications are made to eukaryotic tRNA transcripts?
modification of base and ribose moieties
removal of the 3´ trailer
cleavage of the 5´ leader by RNase P
CCA is added.
Intron splicing is catalyzed by of the spliceosome which is made up of a class of ribonucleoprotiens called
snRNPs
Much of the protein diversity present in our cells is generated by
alternative splicing of exons
Protein synthesis takes place on
ribosomes
The start signal for most organisms is
AUG
The actual three-dimensional structure of tRNA is a(n):
L-shape
The observation that the last nucleotide in a codon can basepair with more than one base in the tRNA anticodon is the basis for the
Wobble hypothesis.
Amino acids are attached to tRNA molecules at the ____________________ or _____________________ stem.
CCA or acceptor
Aminoacyl-tRNA synthetases contain both an activation site and a(n) __________________ site.
editing
The 70S bacterial ribosome is composed of a 50S and 30S subunit. What is the function of the 30S subunit in translation?
tRNA recognition
alignment of the mRNA on the ribosome to initiate translation
Which of the following is/are required for the initiation of protein synthesis in prokaryotes?
mRNA
The 30S subunit
fMet-tRNAf
GTP
What is the direction of translation of mRNA?
5′ → 3′
Signals that define the beginning and end of protein synthesis are contained in
mRNA
Eukaryotic and prokaryotic translation differs primarily in which step?
Initiation
Which of the following E. coli proteins is responsible for translocation of the mRNA as a result of a conformation change due to the hydrolysis of GTP?
EF-G
The three stages of RNA synthesis are _________________________, __________________________, and ____________________________.
Initiation, elongation, termination
Eukaryotic RNA polymerases differ in their sensitivity to the mushroom toxin _____________________.
α-amanitin
What are the names for the tRNA binding sites on the ribosome? ___________________________, ___________________________, and ________________________________.
A, P, E or aminoacyl, peptidyl, exit
