Assignment 10, Chapter 14-15

Two potential functions that eukaryotic cells perform to regulate transcription are A)DNA methylation and histone modification. B)DNA amplification and histone methylation. C)DNA methylation and histone amplification. D)histone amplification and DNA acetylation. E)DNA acetylation and methylation.

A)DNA methylation and histone modification.

Which of the following is a function of a poly-A tail in mRNA? A)It helps protect the mRNA from degradation by hydrolytic enzymes. B)It is a sequence that codes for the binding of RNA polymerase to the DNA. C)It indicates the site of translational termination. D)It adds the modified guanine to the 3' end of the mRNA.

A)It helps protect the mRNA from degradation by hydrolytic enzymes.

What is a ribozyme? A)an RNA with enzymatic activity B)an enzyme that uses RNA as a substrate C)an enzyme that synthesizes RNA primers during DNA replication D)an enzyme that synthesizes RNA as part of the transcription process E)an enzyme that catalyzes the association between the large and small ribosomal subunits

A)an RNA with enzymatic activity

Accuracy in the translation of mRNA into the sequence of amino acids in a polypeptide depends on specificity in which of the following? A)bonding of the anticodon to the codon and the attachment of amino acids to tRNAs B)shape of the A and P sites of ribosomes C)attachment of amino acids to tRNAs D)binding of ribosomes to mRNA

A)bonding of the anticodon to the codon and the attachment of amino acids to tRNAs

What would occur if the repressor of an inducible operon were mutated so it could NOT bind the operator? A)continuous transcription of the operon's genes B)irreversible binding of the repressor to the promoter C)reduced transcription of the operon's genes D)buildup of a substrate for the pathway controlled by the operon

A)continuous transcription of the operon's genes

Which of the following is NOT true of RNA processing? A)RNA splicing can be catalyzed by spliceosomes. B)Exons are cut out before mRNA leaves the nucleus. C)Ribozymes may function in RNA splicing. D)Nucleotides may be added at both ends of the RNA.

B)Exons are cut out before mRNA leaves the nucleus.

Which of the following best describes the significance of the TATA box in eukaryotic promoters? A)It sets the reading frame of the mRNA. B)It is the recognition site for a specific transcription factor. C)It signals the end of the nucleotide sequence of the gene. D)It is the recognition site for ribosomal binding.

B)It is the recognition site for a specific transcription factor.

Gene expression can be blocked by small RNA molecules called siRNAs. What is this process called? A)RNA targeting B)RNA interference C)RNA disposal D)RNA blocking

B)RNA interference

Altering patterns of gene expression in prokaryotes would most likely contribute to the organism's survival in which of the following ways? A)organizing gene expression so that genes are expressed in a given order B)allowing the organism to adjust to changes in environmental conditions C)allowing young organisms to respond differently than more mature organisms D)allowing each gene to be expressed an equal number of times

B)allowing the organism to adjust to changes in environmental conditions

In a genome-wide expression study using a DNA microarray assay, what is each well used to detect? A)location of a protein produced by a cell B)expression of a specific gene by a cell C)fate of proteins produced by a cell D)location of a gene within a cell

B)expression of a specific gene by a cell

What type of bonding is responsible for maintaining the shape of the tRNA molecule in the figure? A)peptide bonding between amino acids B)hydrogen bonding between base pairs C)ionic bonding between phosphates D)van der Waals interactions between hydrogen atoms E)covalent bonding between sulfur atoms

B)hydrogen bonding between base pairs

Transcription factors in eukaryotes usually have DNA-binding domains as well as other domains that are specific for binding other molecules. In general, which of the following would you expect many of them to be able to bind? A)tRNA B)other transcription factors C)protein-based hormones D)repressors

B)other transcription factors

Which of the following is an example of post-transcriptional control of gene expression? A)the binding of RNA polymerase to transcription factors B)the removal of introns and alternative splicing of exon C)the addition of methyl groups to cytosine bases of DNA D)the binding of transcription factors to a promoter

B)the removal of introns and alternative splicing of exon

The functioning of enhancers is an example of __________. A)the stimulation of translation by initiation factors B)transcriptional control of gene expression C)post-translational control that activates certain proteins D)a eukaryotic equivalent of prokaryotic promoter function

B)transcriptional control of gene expression

Examine the table of codons in the figure. A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide? A)3'-UUU-CCC-AAA-GGG-UUU-CCC B)5'-ACT-TAC-CAT-AAA-CAT-TAC-UGA C)5'-TTT-CCC-AAA-GGG-TTT-CCC D)5'-GGG-AAA-TTT-AAA-CCC-ACT-GGG E)3'-AUG-AAA-GGG-TTT-CCC-AAA-GGG

C)5'-TTT-CCC-AAA-GGG-TTT-CCC

The genetic code is essentially the same for all organisms. Based on this information, one can logically assume which of the following statements to be correct? A)All organisms have experienced convergent evolution. B)The same codons in different organisms translate into the different amino acids. C)A gene from an organism can theoretically be expressed by any other organism. D)Different organisms have different numbers of different types of amino acids. E)DNA was the first genetic material.

C)A gene from an organism can theoretically be expressed by any other organism.

Which of the following does not occur in prokaryotic gene expression, but does occur in eukaryotic gene expression? A)mRNA, tRNA, and rRNA are transcribed. B)RNA polymerase requires a primer to elongate the molecule. C)A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end. D)RNA polymerase binds to the promoter. E)Transcription can begin as soon as translation has begun even a little.

C)A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end.

The nitrogenous base adenine is found in all members of which of the following groups of molecules? A)proteins, carbohydrates, and ATP B)proteins, ATP, and DNA C)ATP, RNA, and DNA D)proteins, triglycerides, and testosterone E)glucose, ATP, and DNA

C)ATP, RNA, and DNA

Which statement about DNA in one of your brain cells is true? A)The majority of genes are likely to be transcribed. B)Most of the DNA codes for protein. C)It is the same as the DNA in one of your liver cells. D)Many genes are grouped into operon-like clusters.

C)It is the same as the DNA in one of your liver cells.

In what way might a point mutation in DNA make a difference in the function of a protein? A)It might exchange one serine codon for a different serine codon. B)It might result in a chromosomal translocation. C)It might substitute a different amino acid in the active site. D)It might exchange one stop codon for another stop codon. E)It might substitute the N-terminus of the polypeptide for the C-terminus.

C)It might substitute a different amino acid in the active site.

In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after he has removed its 5' cap and poly-A tail. Which of the following would you expect him to find? A)The molecule is digested by restriction enzymes in the nucleus. B)The cell recognizes the absence of the tail and adds a new poly-A tail to the mRNA. C)The molecule is degraded by hydrolytic enzymes because it is no longer protected at the 5' end and the 3' end. D)The mRNA would not be transported out of the nucleus. E)The molecule attaches to a ribosome and is translated, but more slowly.

C)The molecule is degraded by hydrolytic enzymes because it is no longer protected at the 5' end and the 3' end.

If you were to observe the activity of methylated DNA, you would expect it to A)be replicating nearly continuously. B)be unwinding in preparation for protein synthesis. C)be transcriptionally inactive. D)induce protein synthesis by not allowing repressors to bind to it. E)be very actively transcribed and translated.

C)be transcriptionally inactive.

Transcription of the genes in an inducible operon A)begins when the product of the metabolic pathway is present. B)ceases when the product of the metabolic pathway is present. C)begins when the substrate of the metabolic pathway is present. D)occurs continuously in the cell.

C)begins when the substrate of the metabolic pathway is present.

A eukaryotic transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that A)many nucleotides are needed to code for each amino acid. B)there are termination exons near the beginning of mRNA. C)many noncoding stretches of nucleotides are present in eukaryotic DNA. D)there is redundancy in the genetic code.

C)many noncoding stretches of nucleotides are present in eukaryotic DNA

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is A)5' TCA 3'. B)3' ACU 5'. C)3' UGA 5'. D)3' UCA 5'. E)either UCA or TCA, depending on wobble in the first base.

D)3' UCA 5'.

RNA polymerase moves in which direction along the DNA? A)5' to 3' along whichever strand it's on B)3' to 5' along the nontemplate strand C)5' to 3' along the double-stranded DNA D)3' to 5' along the template strand E)5' to 3' along the template strand

D)3' to 5' along the template strand

Given the locally unwound double strand in the figure, in which direction does the RNA polymerase move? A)5' → 3' along the template strand B)3' → 5' along the complementary strand C)5' → 3' along the complementary strand D)3' → 5' along the template strand E)5' → 3' along the double-stranded DNA

D)3' → 5' along the template strand

Which of the following statements correctly describes the function of a signal peptide? A)It terminates translation of the messenger RNA. B)It causes RNA polymerase to bind DNA and initiate transcription. C)It leads the initiation of transcription. D)It assists in the translocation of polypeptides across the ER membrane. E)It directs an mRNA molecule into the Golgi apparatus.

D)It assists in the translocation of polypeptides across the ER membrane.

What is the function of the release factor in translation? A)It releases the ribosome from the ER to allow polypeptides into the cytosol. B)It releases the amino acid from its tRNA to allow the amino acid to form a peptide bond. C)It separates tRNA in the A site from the growing polypeptide. D)It binds to the stop codon in the A site in place of a tRNA.

D)It binds to the stop codon in the A site in place of a tRNA.

Which of the following statements correctly describes alternative RNA splicing? A)It is a mechanism that can increase the rate of transcription. B)It increases the rate of transcription. C)It allows the production of similar proteins from different RNAs. D)It can allow the production of proteins of different sizes and functions from a single mRNA.

D)It can allow the production of proteins of different sizes and functions from a single mRNA.

What is the effect of a nucleotide-pair substitution that results in a nonsense mutation in a gene? A)It changes an amino acid in the encoded protein. B)It alters the reading frame of the mRNA. C)It has no effect on the amino acid sequence of the encoded protein. D)It introduces a premature stop codon into the mRNA.

D)It introduces a premature stop codon into the mRNA.

Which of the following statements is true about protein synthesis in prokaryotes? A)Unlike eukaryotes, prokaryotes require no initiation or elongation factors. B)Extensive RNA processing is required before prokaryotic transcripts can be translated. C)Prokaryotic cells have multiple mechanisms for targeting proteins to the appropriate cellular organelles. D)Translation can begin while transcription is still in progress.

D)Translation can begin while transcription is still in progress.

Of the following, which is the most current and complete description of a gene? A)a unit of heredity that causes formation of a phenotypic characteristic B)a DNA-RNA sequence combination that results in an enzymatic product C)a discrete unit of hereditary information that consists of a sequence of amino acids D)a DNA sequence that is expressed to form a functional product: either RNA or polypeptide E)a DNA subunit that codes for a single complete protein

D)a DNA sequence that is expressed to form a functional product: either RNA or polypeptide

When translating secretory or membrane proteins, ribosomes are directed to the ER membrane by A)a specific characteristic of the ribosome itself, which distinguishes free ribosomes from bound ribosomes. B)moving through a specialized channel of the nucleus. C)a signal sequence of RNA that precedes the start codon of the message. D)a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane. E)a chemical signal given off by the ER.

D)a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane.

Transcription in eukaryotes requires which of the following in addition to RNA polymerase? A)ribosomes and tRNA B)aminoacyl-tRNA synthetase C)the protein product of the promoter D)several transcription factors E)start and stop codons

D)several transcription factors

In the transcription event of the DNA in the figure, where would the promoter be located? A)to the right of the sense strand B)to the left of the template strand C)to the left of the sense strand D)to the right of the template strand E)at the 3' end of the newly made RNA

D)to the right of the template strand

The tryptophan operon in some bacteria is a repressible operon that is A)turned on only when tryptophan is present in the growth medium. B)turned on only when glucose is present in the growth medium. C)turned off only when glucose is present in the growth medium. D)turned off whenever tryptophan is added to the growth medium. E)permanently turned on.

D)turned off whenever tryptophan is added to the growth medium.

Examine the table of codons in the figure. A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be A)5'-TTG-CTA-CAG-TAG-3'. B)5'-AUG-CTG-CAG-TAT-3'. C)3'-AAC-GAC-GUC-AUA-5'. D)3'-AAA-AAT-ATA-ACA-5'. E)3'-AAA-GAA-TAA-CAA-5'.

E)3'-AAA-GAA-TAA-CAA-5'.

What must happen to a newly made polypeptide before it can be secreted from a cell? A)Its signal sequence must cause it to be encased in a vesicle as soon as it is translated. B)Its signal sequence must target it to the plasma membrane, where it causes exocytosis. C)It must be translated by a ribosome that remains free of attachment to the ER. D)Its signal sequence must be cleaved off before the polypeptide can enter the ER. E)Its signal sequence must target it to the ER, after which it goes to the Golgi.

E)Its signal sequence must target it to the ER, after which it goes to the Golgi.

Which of the following statements best describes the termination of transcription in prokaryotes? A)Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome. B)RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA. C)RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase. D)RNA polymerase transcribes through an intron, which causes the polymerase to let go of the transcript. E)RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.

E)RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.

Which of the following types of mutations could result in a frameshift mutation? A)deletion of three consecutive bases B)a base deletion only C)a base substitution only D)a base insertion only E)either an insertion or a deletion of a base

E)either an insertion or a deletion of a base

Which of the following molecules, when taken up by the cell, binds to the repressor so that the repressor no longer binds to the operator? A)promoter B)repressor C)corepressor D)ubiquitin E)inducer

E)inducer