What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA?
transcription
What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?
translation
What name is given to the process in which pre-mRNA is edited into mRNA?
RNA processing
Polypeptides are assembled from _____.
amino acids
RNA processing converts the RNA transcript into _____.
mRNA
True or false? A codon is a group of three bases that can specify more than one amino acid.
False
Which of the following statements about mutations is false?
A knock-out mutation results in a total absence of the mutated protein.
If a DNA sequence is altered from TAGCTGA to TAGTGA, what kind of mutation has occurred?
Deletion
Which mutation(s) would not change the remainder of the reading frame of a gene sequence that follows the mutation(s)?
One addition and one deletion mutation.
If the sequence ATGCATGTCAATTGA were mutated such that a base were inserted after the first G and the third T were deleted, how many amino acids would be changed in the mutant protein?
Two
If a mutated DNA sequence produces a protein that differs in one central amino acid from the normal protein, which of the following kinds of mutations could have occurred?
An addition mutation and a deletion mutation.
In the diagram below, the gray unit represents _____.
RNA polymerase
In the diagram below, the green unit represents _____.
the promoter
In the diagram below, the two blue strands represent _____.
DNA
Which of these correctly illustrates the pairing of DNA and RNA nucleotides?
GTTACG
CAAUGC
The direction of synthesis of an RNA transcript is _____.
5' —> 3'
What is the process called that converts the genetic information stored in DNA to an RNA copy?
Transcription
DNA does not store the information to synthesize which of the following?
Organelles
Transcription begins at a promoter. What is a promoter?
A site in DNA that recruits the RNA Polymerase
Which of the following statements best describes the promoter of a protein-coding gene?
The promoter is a nontranscribed region of a gene.
What determines which base is to be added to an RNA strand during transcription?
Base pairing between the DNA template strand and the RNA nucleotides
Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand?
Complementary
What happens to RNA polymerase II after it has completed transcription of a gene?
It is free to bind to another promoter and begin transcription.
Which of the following terms associated with transcription describe regions of nucleic acid?
- terminator
- gene
- promoter
During transcription in eukaryotes, a type of RNA polymerase called RNA polymerase II moves along the template strand of the DNA in the 3'→5' direction. However, for any given gene, either strand of the double-stranded DNA may function as the template strand.
For any given gene, what ultimately determines which DNA strand serves as the template strand?
the base sequence of the gene's promoter
After transcription begins, several steps must be completed before the fully processed mRNA is ready to be used as a template for protein synthesis on the ribosomes.
Which three statements correctly describe the processing that takes place before a mature mRNA exits the nucleus?
- A cap consisting of a modified guanine nucleotide is added to the 5' end of the pre-mRNA.
- A poly-A tail (50-250 adenine nucleotides) is added to the 3' end of the pre-mRNA.
- Noncoding sequences called introns are spliced out by molecular complexes called spliceosomes.
During RNA processing a(n) _____ is added to the 5' end of the RNA.
modified guanine nucleotide
During RNA processing a(n) _____ is added to the 3' end of the RNA.
a long string of adenine nucleotides
Spliceosomes are composed of _____.
snRNPs and other proteins
The RNA segments joined to one another by spliceosomes are _____.
exons
Translation occurs in the _____.
cytoplasm
Where does translation take place?
Ribosome
Which nucleic acid is translated to make a protein?
mRNA
Which of the following processes is an example of a post-translational modification?
Phosphorylation
Which of the following steps occurs last in the initiation phase of translation?
The large ribosomal subunit joins the complex.
At which site do new aminoacyl tRNAs enter the ribosome during elongation?
A-site
What is meant by translocation?
The ribosome slides one codon down the mRNA.
True or false. A tRNA with an anticodon complementary to the stop codon catalyzes the reaction by which translation is terminated.
False
Which of these is a tRNA?
B
What enzyme catalyzes the attachment of an amino acid to tRNA?
aminoacyl-tRNA synthetase
The tRNA anticodon, GAC, is complementary to the mRNA codon with the sequence _____.
CUG
What is the name of the process shown in the diagram?
initiation (of translation)
The initiator tRNA attaches at the ribosome's _____ site.
P
The RNA that has an amino acid attached to it, and that binds to the codon on the mRNA, is called a ____
tRNA
Amino acids are attached to tRNA by enzymes called ________
aminoacyl-tRNA synthetase
The process, performed by the ribosome, of reading mRNA and synthesizing a protein is called _____
translation.
_____ of translation always happens at the start codon of the mRNA.
Initiation
______ of translation happens when the ribosome hits a stop codon on the mRNA.
Termination
Generally speaking, which of the following mutations would most severely affect the protein coded for by a gene?
a frameshift deletion at the beginning of the gene
Which of the following statements best defines the term operon?
An operon is a region of DNA that codes for a series of functionally related genes under the control of the same promoter.
What molecule binds to promoters in bacteria and transcribes the coding regions of the genes?
RNA polymerase
What is allosteric regulation?
In allosteric regulation, a small molecule binds to a large protein and causes it to change its shape and activity.
Under which conditions are the lac structural genes expressed most efficiently?
No glucose, high lactose
What happens to the expression of the lacI gene if lactose is not available in the cell?
There is no change—the lacI gene is constitutively expressed.
What is the function of the lacZ gene?
This gene encodes an enzyme, b-galactosidase, which cleaves lactose into glucose and galactose.
Which of the following enzymes converts ATP to cAMP?
Adenylyl cyclase
True or false? The mechanism by which glucose inhibits expression of the lac structural genes is known as catabolite stimulation, whereas the mechanism by which lactose stimulates expression of the lac structural genes is known as allosteric regulation.
False
The operon model of the regulation of gene expression in bacteria was proposed by _____.
Jacob and Monod
Which of these is NOT a component of the lac operon?
regulatory gene only
Regulatory proteins bind to _____.
the operator
In the presence of a regulatory protein the lac operon is _____.
not transcribed
Which of these is a regulatory gene?
D
A(n) ____ is a stretch of DNA consisting of an operator, a promoter, and genes for a related set of proteins, usually making up an entire metabolic pathway.
operon
The ________ is/are arranged sequentially after the promoter.
genes of an operon
A(n) ______ is a specific nucleotide sequence in DNA that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place.
promoter
A(n) _____ codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes.
regulatory gene
Regulatory proteins bind to the _____ to control expression of the operon.
operator
A(n) _____ is a protein that inhibits gene transcription. In prokaryotes, this protein binds to the DNA in or near the promoter.
repressor
A(n) _______ is a specific small molecule that binds to a bacterial regulatory protein and changes its shape so that it cannot bind to an operator, thus switching an operon on.
inducer
_____ bind(s) to DNA enhancer regions.
Activators
Which of these indicates an enhancer region?
A
Which of these directly bind(s) to the promoter?
C & D
Enzyme complexes that break down protein are called _____.
proteasomes
The nuclear membrane's role in the regulation of gene expression involves _____.
regulating the transport of mRNA to the cytoplasm
What is the function of a spliceosome?
RNA processing
Protein-phosphorylating enzymes' role in the regulation of gene expression involves _____.
protein activation
Which of the following terms describes the DNA–protein complexes that look like beads on a string?
Nucleosome
Which of the following regulatory elements is not composed of DNA sequences?
Activators
True or false? Regulatory and basal transcription factors regulate transcription by binding to the promoter.
False
Which of the following regulatory DNA sequences might be located thousands of nucleotides away from the transcription start site of a gene?
Enhancer
Which of the following events in transcription initiation likely occurs last?
RNA polymerase binds to the promoter of the gene.
True or false? One possible way to alter chromatin structure such that genes could be transcribed would be to make histone proteins more positively charged.
False