Question 1

Which of the following is not true of RNA processing?

Accepted Answer

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. 
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. A

Question 2

A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. What would be a potential consequence for a cell in which this happens? Remember that phenylalanine may be encoded by multiple codons.

Accepted Answer

A)  None of the proteins in the cell will contain phenylalanine. 
B)  Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. 
C)  The cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons. 
D)  The ribosome will skip a codon every time a UUU is encountered. 
A)  None of the proteins in the cell will contain phenylalanine. 
B)  Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. 
C)  The cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons. 
D)  The ribosome will skip a codon every time a UUU is encountered. B

Question 3

Which of the following statements correctly describes the function of a signal peptide?

Accepted Answer

A)  It directs an mRNA molecule into the Golgi apparatus. 
B)  It causes RNA polymerase to bind DNA and initiate transcription. 
C)  It terminates translation of the messenger RNA. 
D)  It assists in the translocation of polypeptides across the ER membrane. 
E)  It leads the initiation of transcription. 
A)  It directs an mRNA molecule into the Golgi apparatus. 
B)  It causes RNA polymerase to bind DNA and initiate transcription. 
C)  It terminates translation of the messenger RNA. 
D)  It assists in the translocation of polypeptides across the ER membrane. 
E)  It leads the initiation of transcription. D

Question 4

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. What is the most likely result of this mutation in the protein product?

Accepted Answer

A)  a base-pair substitution 
B)  a nucleotide mismatch 
C)  a frameshift mutation 
D)  a polypeptide missing an amino acid 
E)  a nonsense mutation 
A)  a base-pair substitution 
B)  a nucleotide mismatch 
C)  a frameshift mutation 
D)  a polypeptide missing an amino acid 
E)  a nonsense mutation

Question 5

In the 1920s, Hermann Muller discovered that X-rays caused genetic changes in Drosophila. In a related series of experiments in the 1940s, other scientists discovered that other types of chemicals have a similar effect. A new chemical food additive is developed by a cereal manufacturer. Why is it necessary to test for its ability to cause mutation?

Accepted Answer

A)  We worry that it might cause mutation in cereal grain plants. 
B)  We want to make sure that it does not emit radiation. 
C)  We want to be sure that it increases the rate of mutation sufficiently. 
D)  We want to prevent any chance that it might cause mutations. 
A)  We worry that it might cause mutation in cereal grain plants. 
B)  We want to make sure that it does not emit radiation. 
C)  We want to be sure that it increases the rate of mutation sufficiently. 
D)  We want to prevent any chance that it might cause mutations.

Question 6

Accuracy in the translation of mRNA into the sequence of amino acids in a polypeptide depends on specificity in which of the following?

Accepted Answer

A)  binding of ribosomes to mRNA 
B)  shape of the A and P sites of ribosomes 
C)  attachment of amino acids to tRNAs 
D)  bonding of the anticodon to the codon and the attachment of amino acids to tRNAs 
A)  binding of ribosomes to mRNA 
B)  shape of the A and P sites of ribosomes 
C)  attachment of amino acids to tRNAs 
D)  bonding of the anticodon to the codon and the attachment of amino acids to tRNAs

Question 7

Of the following, which is the most current and complete description of a gene?

Accepted Answer

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 
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

Question 8

A particular triplet of bases in the template strand of DNA is 5'-AGT-3'. The corresponding codon for the mRNA transcribed is

Accepted Answer

A)  3'-UCA-5'. 
B)  3'-UGA-5'. 
C)  5'-TCA-3'. 
D)  3'-ACU-5'. 
E)  either UCA or TCA, depending on wobble in the first base. 
A)  3'-UCA-5'. 
B)  3'-UGA-5'. 
C)  5'-TCA-3'. 
D)  3'-ACU-5'. 
E)  either UCA or TCA, depending on wobble in the first base.

Question 9

Which of the following is not true of a codon?

Accepted Answer

A)  It may code for the same amino acid as another codon. 
B)  It never codes for more than one amino acid. 
C)  It extends from one end of a tRNA molecule. 
D)  It is the basic unit of the genetic code. 
A)  It may code for the same amino acid as another codon. 
B)  It never codes for more than one amino acid. 
C)  It extends from one end of a tRNA molecule. 
D)  It is the basic unit of the genetic code.

Question 10

Figure 14.2
-Examine the table of codons in Figure 14.2. A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be

Accepted Answer

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'. 
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'.

Question 11

Which of the following statements is true about protein synthesis in prokaryotes?

Accepted Answer

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 multiple mechanisms for targeting proteins to the appropriate cellular organelles. 
D)  Unlike eukaryotes, prokaryotes require no initiation or elongation factors. 
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 multiple mechanisms for targeting proteins to the appropriate cellular organelles. 
D)  Unlike eukaryotes, prokaryotes require no initiation or elongation factors.

Question 12

Which of the following best describes the significance of the TATA box in eukaryotic promoters?

Accepted Answer

A)  It is the recognition site for a specific transcription factor. 
B)  It sets the reading frame of the mRNA. 
C)  It is the recognition site for ribosomal binding. 
D)  It signals the end of the nucleotide sequence of the gene. 
A)  It is the recognition site for a specific transcription factor. 
B)  It sets the reading frame of the mRNA. 
C)  It is the recognition site for ribosomal binding. 
D)  It signals the end of the nucleotide sequence of the gene.

Question 13

When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following sets of structures would you be able to isolate from the cell?

Accepted Answer

A)  an assembled ribosome with a polypeptide attached to the tRNA in the P site 
B)  separated ribosomal subunits, a polypeptide, and free tRNA 
C)  an assembled ribosome with a separated polypeptide 
D)  separated ribosomal subunits with a polypeptide attached to the tRNA 
A)  an assembled ribosome with a polypeptide attached to the tRNA in the P site 
B)  separated ribosomal subunits, a polypeptide, and free tRNA 
C)  an assembled ribosome with a separated polypeptide 
D)  separated ribosomal subunits with a polypeptide attached to the tRNA

Question 14

Please use the following information to answer the question(s) below.
A part of an mRNA molecule with the following sequence is being read by a ribosome: 5'-CCG-ACG-3' (mRNA). The charged transfer RNA molecules shown in Figure 14.4 (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.   Figure 14.4
-The anticodon loop of the first tRNA that will complement this mRNA is

Accepted Answer

A)  3'-GGC-5'. 
B)  5'-GGC-3'. 
C)  5'-ACG-3'. 
D)  5'-UGC-3'. 
E)  3'-UGC-5'. 
A)  3'-GGC-5'. 
B)  5'-GGC-3'. 
C)  5'-ACG-3'. 
D)  5'-UGC-3'. 
E)  3'-UGC-5'.

Question 15

Which component is not directly involved in translation?

Accepted Answer

A)  GTP 
B)  DNA 
C)  tRNA 
D)  ribosomes 
A)  GTP 
B)  DNA 
C)  tRNA 
D)  ribosomes

Question 16

What is the function of GTP in translation?

Accepted Answer

A)  GTP provides the energy for the formation of the initiation complex, using initiation factors. 
B)  GTP is hydrolyzed to provide phosphate groups for tRNA binding. 
C)  GTP is hydrolyzed to provide energy for breaking peptide bonds. 
D)  GTP supplies phosphates and energy to make ATP from ADP. 
A)  GTP provides the energy for the formation of the initiation complex, using initiation factors. 
B)  GTP is hydrolyzed to provide phosphate groups for tRNA binding. 
C)  GTP is hydrolyzed to provide energy for breaking peptide bonds. 
D)  GTP supplies phosphates and energy to make ATP from ADP.

Question 17

Please use the following information to answer the question(s) below.
The enzyme polynucleotide phosphorylase randomly assembles nucleotides into a polynucleotide polymer.
-You add polynucleotide phosphorylase to a solution of adenosine triphosphate and guanosine triphosphate. How many artificial mRNA three-nucleotide codons would be possible?

Accepted Answer

A)  3 
B)  4 
C)  8 
D)  16 
E)  6 
A)  3 
B)  4 
C)  8 
D)  16 
E)  6

Question 18

Use the following model of a eukaryotic transcript to answer the question. E1-4 refer to the exons and I1-3 refer to the introns in the pre-mRNA transcript.
5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3'
Which components of the previous molecule will also be found in mRNA in the cytosol?

Accepted Answer

A)  5' UTR I1 I2 I3 UTR 3' 
B)  5' E1 E2 E3 E4 3' 
C)  5' UTR E1 E2 E3 E4 UTR 3' 
D)  5' I1 I2 I3 3' 
E)  5' E1 I1 E2 I2 E3 I3 E4 3' 
A)  5' UTR I1 I2 I3 UTR 3' 
B)  5' E1 E2 E3 E4 3' 
C)  5' UTR E1 E2 E3 E4 UTR 3' 
D)  5' I1 I2 I3 3' 
E)  5' E1 I1 E2 I2 E3 I3 E4 3'

Question 19

Figure 14.1
-Examine the simple metabolic pathway in Figure 14.1. A mutation results in a defective enzyme A. Which of the following results would be a consequence of that mutation?

Accepted Answer

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 
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

Question 20

Figure 14.1
-Examine the simple metabolic pathway in Figure 14.1. If A, B, and C are all required for growth, a strain mutant for the gene-encoding enzyme 2 would be capable of growing on which of the following media?

Accepted Answer

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 
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

Exam 14: Gene Expression: From Gene to Protein

Which of the following is not true of RNA processing?

A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. What would be a potential consequence for a cell in which this happens? Remember that phenylalanine may be encoded by multiple codons.

Which of the following statements correctly describes the function of a signal peptide?

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. What is the most likely result of this mutation in the protein product?

Accuracy in the translation of mRNA into the sequence of amino acids in a polypeptide depends on specificity in which of the following?

Of the following, which is the most current and complete description of a gene?

A particular triplet of bases in the template strand of DNA is 5'-AGT-3'. The corresponding codon for the mRNA transcribed is

Which of the following is not true of a codon?

Figure 14.2 -Examine the table of codons in Figure 14.2. A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be

Which of the following statements is true about protein synthesis in prokaryotes?

Which of the following best describes the significance of the TATA box in eukaryotic promoters?

When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following sets of structures would you be able to isolate from the cell?

Which component is not directly involved in translation?

What is the function of GTP in translation?

Use the following model of a eukaryotic transcript to answer the question. E1-4 refer to the exons and I1-3 refer to the introns in the pre-mRNA transcript. 5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3' Which components of the previous molecule will also be found in mRNA in the cytosol?

Figure 14.1 -Examine the simple metabolic pathway in Figure 14.1. A mutation results in a defective enzyme A. Which of the following results would be a consequence of that mutation?

Figure 14.1 -Examine the simple metabolic pathway in Figure 14.1. If A, B, and C are all required for growth, a strain mutant for the gene-encoding enzyme 2 would be capable of growing on which of the following media?

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Regulation of Gene Expression

Development, Stem Cells, and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition, Nutrition, and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons, Synapses, and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

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