48) Which of the following DNA mutations is the most likely to be damaging to the protein it specifies?
A) a base-pair deletion
B) a codon substitution
C) a substitution in the last base of a codon
D) a codon deletion
E) a point mutation
49) Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of
a protein?
A) a base substitution
B) a base deletion near the start of a gene
C) a base deletion near the end of the coding sequence, but not in the terminator codon
D) deletion of three bases near the start of the coding sequence, but not in the initiator codon
E) a base insertion near the end of the coding sequence, but not in the terminator codon
50) The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon.
This results in
A) a base-pair substitution.
B) a nucleotide mismatch.
C) a frameshift mutation.
D) a polypeptide missing an amino acid.
E) a nonsense mutation.
51) Which of the following mutations is most likely to cause a phenotypic change?
A) a duplication of all or most introns
B) a large inversion whose ends are each in intergenic regions
C) a nucleotide substitution in an exon coding for a transmembrane domain
D) a single nucleotide deletion in an exon coding for an active site
E) a frameshift mutation one codon away from the 3′ end of the nontemplate strand
52) If a protein is coded for by a single gene and this protein has six clearly defined domains, which
number of exons below is the gene likely to have?
A) 1
B) 5
C) 8
D) 12
E) 14
53) Which of the following statements is true about protein synthesis in prokaryotes?
A) Extensive RNA processing is required before prokaryotic transcripts can be translated.
B) Translation can begin while transcription is still in progress.
C) Prokaryotic cells have complicated mechanisms for targeting proteins to the appropriate cellular
organelles.
D) Translation requires antibiotic activity.
E) Unlike eukaryotes, prokaryotes require no initiation or elongation factors.
54) Of the following, which is the most current description of a gene?
A) a unit of heredity that causes formation of a phenotypic characteristic
B) a DNA subunit that codes for a single complete protein
C) a DNA sequence that is expressed to form a functional product: either RNA or polypeptide
D) a DNA—RNA sequence combination that results in an enzymatic product
E) a discrete unit of hereditary information that consists of a sequence of amino acids
55) Gene expression in the domain Archaea in part resembles that of bacteria and in part that of the
domain Eukarya. In which way is it most like the domain Eukarya?
A) Domain Archaea have numerous transcription factors.
B) Initiation of translation is like that of domain Eukarya.
C) There is only one RNA polymerase.
D) Transcription termination often involves attenuation.
E) Post-transcriptional splicing is like that of Eukarya.
56) Which of the following is true of transcription in domain Archaea?
A) It is regulated in the same way as in domain Bacteria.
B) There is only one kind of RNA polymerase.
C) It is roughly simultaneous with translation.
D) Promoters are identical to those in domain Eukarya.
E) It terminates in a manner similar to bacteria.
57) In comparing DNA replication with RNA transcription in the same cell, which of the following is
true only of replication?
A) It uses RNA polymerase.
B) It makes a new molecule from its 5′ end to its 3′ end.
C) The process is extremely fast once it is initiated.
D) The process occurs in the nucleus of a eukaryotic cell.
E) The entire template molecule is represented in the product.
58) In order for a eukaryotic gene to be engineered into a bacterial colony to be expressed, what must be
included in addition to the coding exons of the gene?
A) the introns
B) eukaryotic polymerases
C) a bacterial promoter sequence
D) eukaryotic ribosomal subunits
E) eukaryotic tRNAs
59) When the genome of a particular species is said to include 20,000 protein-coding regions, what does
this imply?
A) There are 20,000 genes.
B) Each gene codes for one protein.
C) Any other regions are “junk” DNA.
D) There are also genes for RNAs other than mRNA.
E) The species is highly evolved.
16
Art Questions
The following question refers to this figure of a simple metabolic pathway:
60) According to Beadle and Tatum’s hypothesis, how many genes are necessary for this pathway?
A) 0
B) 1
C) 2
D) 3
E) It cannot be determined from the pathway.
61) A mutation results in a defective enzyme A. Which of the following would be a consequence of that
mutation?
A) an accumulation of A and no production of B and C
B) an accumulation of A and B and no production of C
C) an accumulation of B and no production of A and C
D) an accumulation of B and C and no production of A
E) an accumulation of C and no production of A and B
62) If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding enzyme A
would be able to grow on which of the following media?
A) minimal medium
B) minimal medium supplemented with nutrient A only
C) minimal medium supplemented with nutrient B only
D) minimal medium supplemented with nutrient C only
E) minimal medium supplemented with nutrients A and C
63) If A, B, and C are all required for growth, a strain mutant for the gene-encoding enzyme B would be
capable of growing on which of the following media?
A) minimal medium
B) minimal medium supplemented with A only
C) minimal medium supplemented with B only
D) minimal medium supplemented with C only
E) minimal medium supplemented with nutrients A and B
The following questions refer to this table of codons.
64) 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) 3′ AAC-GAC–GUC-AUA 5′.
C) 5′ AUG-CTG-CAG-TAT 3′.
D) 3′ AAA-AAT-ATA-ACA 5′.
E) 3′ AAA-GAA-TAA-CAA 5′.
65) What amino acid sequence will be generated, based on the following mRNA codon sequence?
5′ AUG-UCU-UCG-UUA-UCC-UUG 3′
A) met-arg-glu-arg-glu-arg
B) met-glu-arg-arg-glu-leu
C) met-ser-leu-ser-leu-ser
D) met-ser-ser-leu-ser-leu
E) met-leu-phe-arg-glu-glu
66) 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) 3′ AUG-AAA-GGG-TTT–CCC–AAA-GGG
C) 5′ TTT-CCC–AAA-GGG-TTT–CCC
D) 5′ GGG-AAA–TTT-AAA-CCC-ACT-GGG
E) 5′ ACT-TAC-CAT-AAA-CAT-TAC-UGA
Use this representation to answer the following questions.
DNA template strand 5′ ____________________________ 3′
DNA complementary strand 3′ ____________________________ 5′
67) Given the locally unwound double strand above, in which direction does the RNA polymerase
move?
A) 3′ → 5′ along the template strand
B) 5′ → 3′ along the template strand
C) 3′ → 5′ along the complementary strand
D) 5′ → 3′ along the complementary strand
E) 5′ → 3′ along the double-stranded DNA
68) In the transcription event of the previous DNA, where would the promoter be located?
A) at the 3′ end of the newly made RNA
B) to the right of the template strand
C) to the left of the template strand
D) to the right of the sense strand
E) to the left of the sense strand
The following information should be used for the next few questions.
A part of an mRNA molecule with the following sequence is being read by a ribosome: 5′ CCG-ACG 3′
(mRNA). The following charged transfer RNA molecules (with their anticodons shown in the 3′ to 5′
direction) are available. Two of them can correctly match the mRNA so that a dipeptide can form.
tRNA Anticodon
Amino Acid
GGC
CGU
UGC
CCG
ACG
CGG
Proline
Alanine
Threonine
Glycine
Cysteine
Alanine
69) The dipeptide that will form will be
A) cysteine-alanine.
B) proline-threonine.
C) glycine-cysteine.
D) alanine-alanine.
E) threonine-glycine.
70) The anticodon loop of the first tRNA that will complement this mRNA is
A) 3′ GGC 5′
B) 5′ GGC 3′
C) 5′ ACG 3′
D) 5′ UGC 3′
E) 3′ UGC 5′
71) What type of bonding is responsible for maintaining the shape of the tRNA molecule?
A) covalent bonding between sulfur atoms
B) ionic bonding between phosphates
C) hydrogen bonding between base pairs
D) van der Waals interactions between hydrogen atoms
E) peptide bonding between amino acids
72) The figure represents tRNA that recognizes and binds a particular amino acid (in this instance,
phenylalanine). Which codon on the mRNA strand codes for this amino acid?
A) UGG
B) GUG
C) GUA
D) UUC
E) CAU
73) The tRNA shown in the figure has its 3′ end projecting beyond its 5′ end. What will occur at this 3′
end?
A) The codon and anticodon complement one another.
B) The amino acid binds covalently.
C) The excess nucleotides (ACCA) will be cleaved off at the ribosome.
D) The small and large subunits of the ribosome will attach to it.
E) The 5′ cap of the mRNA will become covalently bound.
Scenario Questions
Use the following information to answer the next few questions.
The enzyme polynucleotide phosphorylase randomly assembles nucleotides into a polynucleotide
polymer.
74) You add polynucleotide phosphorylase to a solution of adenosine triphosphate and guanosine
triphosphate. How many artificial mRNA 3 nucleotide codons would be possible?
A) 3
B) 4
C) 8
D) 16
E) 64
75) You add polynucleotide phosphorylase to a solution of ATP, GTP, and UTP. How many artificial
mRNA 3 nucleotide codons would be possible?
A) 3
B) 6
C) 9
D) 27
E) 81
Use the following information to answer the next few questions.
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the
growing polypeptide on the other tRNA (#2) in the ribosome already.
76) Where does tRNA #2 move to after this bonding of lysine to the polypeptide?
A) A site
B) P site
C) E site
D) exit tunnel
E) directly to the cytosol
77) Which component of the complex described enters the exit tunnel through the large subunit of the
ribosome?
A) tRNA with attached lysine (#1)
B) tRNA with polypeptide (#2)
C) tRNA that no longer has attached amino acid
D) newly formed polypeptide
E) initiation and elongation factors
End-of-Chapter Questions
The following questions are from the end-of–chapter “Test Your Understanding” section in Chapter 17
of the textbook.
78) In eukaryotic cells, transcription cannot begin until
A) the two DNA strands have completely separated and exposed the promoter.
B) several transcription factors have bound to the promoter.
C) the 5′ caps are removed from the mRNA.
D) the DNA introns are removed from the template.
E) DNA nucleases have isolated the transcription unit.
79) Which of the following is not true of a codon?
A) It consists of three nucleotides.
B) It may code for the same amino acid as another codon.
C) It never codes for more than one amino acid.
D) It extends from one end of a tRNA molecule.
E) It is the basic unit of the genetic code.
80) The anticodon of a particular tRNA molecule is
A) complementary to the corresponding mRNA codon.
B) complementary to the corresponding triplet in rRNA.
C) the part of tRNA that bonds to a specific amino acid.
D) changeable, depending on the amino acid that attaches to the tRNA.
E) catalytic, making the tRNA a ribozyme.
81) Which of the following is not true of RNA processing?
A) Exons are cut out before mRNA leaves the nucleus.
B) Nucleotides may be added at both ends of the RNA.
C) Ribozymes may function in RNA splicing.
D) RNA splicing can be catalyzed by spliceosomes.
E) A primary transcript is often much longer than the final RNA molecule that leaves the nucleus.
82) Which component is not directly involved in translation?
A) mRNA
B) DNA
C) tRNA
D) ribosomes
E) GTP
83) Which of the following mutations would be most likely to have a harmful effect on an organism?
A) a nucleotide-pair substitution
B) a deletion of three nucleotides near the middle of a gene
C) a single nucleotide deletion in the middle of an intron
D) a single nucleotide deletion near the end of the coding sequence
E) a single nucleotide insertion downstream of, and close to, the start of the coding sequence