ch 12 gene expression at the molecular level
how many distinct aminoacyl-tRNA synthetases does each cell make
-60
directly produced from the transcription of a eukaryotic gene
pre-mRNA
transcription begins near a site in the DNA called the
promoter
molecule exhibits self-splicing
rRNA and tRNA
where the most common eukaryotic ribosome carries out its function
cytosol
intervening sequences transcribed but not translated into protein are
introns
incorrect statement about RNA polymerase in bacteria
it catalyzes the addition of nucleotides to the 5' end of a growing RNA strand
released when an aminoacyl-tRNA synthetase charges a tRNA
AMP and pryophosphate
protein involved in synthesizing messenger RNA in eukaryotes
RNA polymerase I
________ is to transcription as _________ are to translation
RNA polymerase; ribosomes
how many nucleotides are contained in a single codon
3
RNA sequence produced from DNA template strand 3'-TACAATGTAGCC-5'
5'-AUGUUACAUCGG-5' (3')
enables a single gene to encode two or more polypeptides that are different in their amino acid sequence
alternative splicing
N-terminus refers to the presence of this at the 5' end of a polypeptide
amino group
enzyme catalyzes the attachment of amino acids to tRNA molecules
aminoacyl-tRNA synthetase
because more than one codon can specify the same amino acid, the genetic code is said to be
degenerate
a single gene always encodes for an enzyme
false
all enzymes are proteins
false
as part of the transcriptional unit, regulatory sequences are the sites where RNA polymerase and transcription facotrs bind to regulate transcription
false
because of the abundance of ribosomes, translation is NOT an energy costly process for the cell
false
in eukaryotes, 40S and 60S combine to form a 100S ribosome
false
tRNA contains the genetic code for producing a polypeptide
false
the cells of every organism make only a few different tRNA molecules encoded by the same gene
false
translation is a relatively slow process
false
organized unit of DNA sequences that enables a segment of DNA to be transcribed into RNA and ultimately results in formation of a functional product
gene
processes of transcription and translation are collectively known as
gene expression
incorrect statement about RNA processing in eukaryotes
introns are excised out of pre-mRNA to produce the mature mRNA
would occur if a cell's splicesomes were mutated so they no longer functioned normally
introns would remain in the mature mRNA
bond that holds the amino acids of a growing polypeptide chain together during the elongation stage of translation
peptide
NOT a component of the translation machinery
protein polymerase
factors needed to recognize the stop codon and disassemble the translation machinery
release factors
correct sequence of events for the initiation and elongation steps of translation
small ribosomal subunit binds to mRNA, initiator tRNA binds to start codon on mRNA, large ribosomal subunit binds, tRNA entry and peptidyl transfer reaction, translocation of ribosome and release of tRNA
serves as the "translator" or intermediary between an mRNA codon and an amino acid
tRNA
false statement about tRNA
tRNAs can be spliced by splicesomes
true statement about the 5' cap and mRNA processing
the 5' cap is added to the pre-mRNA by splicesomes
basic feature of transcription NOT shared by prokaryotes and eukaryotes
the complexity of protein components involved in transcription is similar for both prokaryotes and eukaryotes
function of the poly-A tail
the poly-A tail increases mRNA stability in eukaryotes
incorrect statement about the mRNA start codon
the start codon is usually GGA
region of structural gene contains the information that specifies an amino acid sequence
transcribed region
process that produces mRNA from DNA
transcription
protein that influences the ability of RNA polymerase to transcribe genes
transcription factors
products of nonstructural genes and are therefore never translated
transfer RNA and ribosomal RNA
what process would a defective ribosome have the most detrimental effect on
translation
DNA is used as a template to make mRNA, which contains the information to make a polypeptide
true
RNA polymerase II of eukaryotes always requires more than one general transcription factor to initiate transcription
true
more than one codon can specify the same amino acid
true
the termination of translation occurs when a release factor recognizes the stop codon
true
molecule provides energy for translation
GTP
anticodon sequence of 5'-AUG-GGC-ACU-CAU-3'
3'-UAC-CCG-UGA-GUA-5'
5'-ACU-UUC-ACU-AUG-UUU-UUA-UCC-UCC-ACU-CCU-UGA-3' results in
Met-Phe-Leu-Ser-Ser-Thr-Pro