bio ch 17
taking into account the wobble hypothesis, which of the following mRNA sequences could be bound to the tRNA anticodon of 3' GGC 5'
5' CCA 3'
in what direction is RNA synthesized during transcription
5' to 3'
Where does an amino acid attach to a tRNA
At the 3′ end
How does RNA polymerase begin transcription in eukaryotes
By binding to promoter sequences in DNA
In bacteria, sigma binds to the polymerase before transcription begins. Bacterial RNA polymerase and sigma form which of the following
Holoenzyme
Which of the following best describes the significance of the TATA box in eukaryotic promoters
It is the binding site for a transcription factor
What is the term for a complex of mRNA bound with multiple ribosomes, each synthesizing its own polypeptide strand
Polyribosome
What prevents the DNA coding strand and RNA from matching exactly in base sequence
RNA has the base uracil (U) rather than the thymine (T) found in the coding strand. Adenine (A) in the DNA template strand specifies a U in the complementary RNA strand
Which of the following transcribes protein-coding genes in eukaryotes
RNA polymerase II
in eukaryotic, transcription normally stops when
RNA polymerase reaches a termination signal on the DNA that leads to the formation of a hairpin loop in the mRNA
which of the following statements best describes the termination of transcription in bacteria
RNA polymerase transcribes a terminator sequence, causing the polymerase to separate from the DNA and release the transcript
In transcription, ______ produces an RNA molecule with a base sequence complementary to the base sequence of the ____
RNA polymerase; DNA template strand
Modifications needed for converting a primary transcript into a mature RNA are called
RNA processing
modifications needed for converting a primary transcript into a mature RNA are called
RNA processing
Which of the following steps for terminating translation are correct and in the right order
Release factor binds to stop codon; polypeptide and uncharged tRNAs are released; ribosome subunits separate
In addition to RNA polymerase, transcription in eukaryotes requires which of the following
Several transcription factors
the ____ of the eukaryotic promoter is analogous to the _____ of the bacterial promoter
TATA box; -10 box
Which of the following best describes the processing of eukaryotic pre-mRNAs in the proper order
The addition of a 5′ cap; removal of introns; Poly (A) tail
Which of the following statements best describes the ribosome binding site
The ribosome binding site is where the small ribosome subunit binds; it is located upstream of the start codon
In bacteria, transcription ends at a distinct site in each gene. Which of the following best describes transcription in eukaryotes
Transcription ends at variable distances from the Poly (A) signal
in bacteria, when does transcription end
When a stem-loop structure forms in the transcribed RNA
which of the following best describes the splicesome
a complex molecular machine that splices introns out of pre-mRNA
which of the following statements about translational initiation in bacteria is true
a specific sequence on the small ribosomal subunit binds a complementary sequence on the mRNA
ribosomes translate mRNAs into proteins with the help of
adaptor molecules called tRNAs
An advantage of introns is that they
allow expression of different exon combinations from one gene
Researchers report that a protein is encoded by a gene with four promoters that give rise to at least eight different mRNAs. What mechanism could account for the production of these different mRNAs from the same gene
alternative splicing
paul zamecnik and his colleagues tracked the fate of radioactive leucine molecules attached to tRNAs. they found that
amino acids are transferred from tRNAs to proteins
which of the following statements about transcription in bacteria and eukaryotes is true
bacteria and eukaryotes rely on proteins that recognize specific DNA sequences in the promoter to initiate transcription
The release factor (RF)
binds to the stop codon in the A site in place of a tRNA
A gene is a
coding and regulatory sequence that directs the production of one or more related polypeptides or RNAs
group 2
group 2
the poly(A) tail at the end of eukaryotic mRNA
helps protect the mRNA from degradation by enzymes in the cytoplasm
in comparison to bacterial transcription, eukaryotic transcription is more complex. which of the following statements best describes why eukaryotic transcription is more complex?
in eukaryotic transcription, the promoters are more diverse, and the primary RNA transcript must be evenly processed
The process of translation, whether in bacteria or eukaryotes, requires tRNAs, amino acids, ribosomal subunits, and
initiation and elongation factors, plus GTP
a primary transcript in the nucleus of a eukaryotic cell is ____ the functional mRNA, whereas a primary transcript in a bacterial cell is ____ the function mRNA
larger than; same size as
what molecule carries a genetic message from DNA to the protein-synthesizing components of the cell
mRNA
in a eukaryotic cell, which of the following statements about post-translational modification of proteins is true
many proteins are modified chemically after they are synthesized
if there were a mutation in a ribosome that prevented tRNA molecules from moving into the E site, how many amino acids would be found in the resulting peptide chain formed on this ribosome
max of 2
according to the wobble hypothesis
more than one codon codes for an amino acid, and codons for the same amino acid tend to have the same nucleotides in the first two positions
to label amino acids within cells, researchers "pulsed" e.coli with radioactive sulfate and "chased" it with an excess of nonradioactive sulfate. they observed that radioactivity was first associated with ribosomes and then later with completed proteins. they concluded that
proteins are synthesized by ribosomes and are subsequently released
during elongation, what substances are used for the polymerization reaction catalyzed by RNA polymerase
ribonucleoside triphosphates
which of the following are proteins that associate with promoters in bacteria during transcription
sigma
what is the maximum number of amino acids in a peptide that would be produced from the following mRNA sequence: 5' AAUCCGUAAAUAGAGACCGAUCAAUUAGCG 3'
six
During RNA splicing, which molecular component of the spliceosome catalyzes the excision reaction
snRNA
what happens to introns in eukaryotic mRNA
snRNPs bind to the primary transcript and form the spliceosome, which removes introns
RNA polymerase reads the template strand. The non-template strand is
the coding strand—its sequence matches the sequence of the RNA that is transcribed from the template strand
which of the following is true of the sequence called TATA box?
the sequence is located 30 base pairs upstream of the transcription site and is important for recognition by RNA polymerase
which of the following factors are associated with transcription in eukaryotes
thee polymerase bases, basal transcription factos, 5' cap, and 3' poly A tail
lack of membrane-bound organelles in bacteria impacts transcription and translation in which way
transcription and translation can occur simultaneously
if a mutation rendered the sigma protein nonfunctional, which of the following would result
transcription of bacterial genes would be reduced or eliminated