Question 1

Suppose that an induced mutation removes most of the 5' end of the 5' UTR. What might result?

Accepted Answer

A)  Removal of the 5' UTR has no effect because the exons are still maintained. 
B)  Removal of the 5' UTR also removes the 5' cap, and the mRNA will quickly degrade. 
C)  The 3' UTR will duplicate and one copy will replace the 5' end. 
D)  The first exon will not be read because I1 will now serve as the UTR. 
E)  Removal of the 5' UTR will result in the strand not binding to tRNAs. 
A)  Removal of the 5' UTR has no effect because the exons are still maintained. 
B)  Removal of the 5' UTR also removes the 5' cap, and the mRNA will quickly degrade. 
C)  The 3' UTR will duplicate and one copy will replace the 5' end. 
D)  The first exon will not be read because I1 will now serve as the UTR. 
E)  Removal of the 5' UTR will result in the strand not binding to tRNAs.

Question 2

If a newly made polypeptide is to be secreted from a cell, what must occur before it is secreted?

Accepted Answer

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

Question 3

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is

Accepted Answer

A)  TTT. 
B)  UUA. 
C)  UUU. 
D)  AAA. 
E)  either UAA or TAA, depending on first base wobble. 
A)  TTT. 
B)  UUA. 
C)  UUU. 
D)  AAA. 
E)  either UAA or TAA, depending on first base wobble.

Question 4

Garrod's information about the enzyme alteration resulting in alkaptonuria led to further elucidation of the same pathway in humans. Phenylketonuria (PKU) occurs when another enzyme in the pathway is altered or missing, resulting in a failure of phenylalanine (phe) to be metabolized to another amino acid: tyrosine. Tyrosine is an earlier substrate in the pathway altered in alkaptonuria. How might PKU affect the presence or absence of alkaptonuria?

Accepted Answer

A)  It would have no effect, because PKU occurs several steps away in the pathway. 
B)  It would have no effect, because tyrosine is also available from the diet. 
C)  Anyone with PKU must also have alkaptonuria. 
D)  Anyone with PKU is born with a predisposition to later alkaptonuria. 
E)  Anyone with PKU has mild symptoms of alkaptonuria. 
A)  It would have no effect, because PKU occurs several steps away in the pathway. 
B)  It would have no effect, because tyrosine is also available from the diet. 
C)  Anyone with PKU must also have alkaptonuria. 
D)  Anyone with PKU is born with a predisposition to later alkaptonuria. 
E)  Anyone with PKU has mild symptoms of alkaptonuria.

Question 5

Use the following model of a eukaryotic transcript to answer the next few questions.
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 6

Which of the following is true of transcription in domain Archaea?

Accepted Answer

A)  It is regulated in the same way as in domain Bacteria. 
B)  There is only one kind of RNA polymerase. 
C)  It produces RNA transcripts that are processed after they leave the nucleus. 
D)  It involves promoters that are identical to those in domain Eukarya. 
E)  It terminates in a manner similar to that in bacteria. 
A)  It is regulated in the same way as in domain Bacteria. 
B)  There is only one kind of RNA polymerase. 
C)  It produces RNA transcripts that are processed after they leave the nucleus. 
D)  It involves promoters that are identical to those in domain Eukarya. 
E)  It terminates in a manner similar to that in bacteria.

Question 7

The following questions refer to the simple metabolic pathway in Figure 14.1.
   Figure 14.1
-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?

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

Question 8

A frameshift mutation could result from

Accepted Answer

A)  a base insertion only. 
B)  a base deletion only. 
C)  a base substitution only. 
D)  deletion of three consecutive bases. 
E)  either an insertion or a deletion of a base. 
A)  a base insertion only. 
B)  a base deletion only. 
C)  a base substitution only. 
D)  deletion of three consecutive bases. 
E)  either an insertion or a deletion of a base.

Question 9

When the genome of a particular species is said to include 20,000 protein-coding regions, what does this imply?

Accepted Answer

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. 
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.

Question 10

The following questions refer to the table of codons in Figure 14.2.
   Figure 14.2
-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?

Accepted Answer

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 
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

Question 11

Suppose that an error in transcription alters the formation of a single tRNA molecule in a cell. The altered tRNA still attaches to the same amino acid (Phe), but its anticodon loop has the sequence AAU, which binds to the mRNA codon UUA (usually specifying leucine, Leu). What will be the effect on translation in this cell?

Accepted Answer

A)  The altered tRNA will cause this mRNA to make only nonfunctioning product. 
B)  The tRNA-Leu will not be able to enter the ribosome to bind to the UUA codon. 
C)  One altered tRNA molecule will be relatively inconsequential because it will compete with many "normal" ones. 
D)  The altered tRNA will be so unstable that it will not participate in translation. 
E)  The altered tRNA will result in an amino acid variant in all copies of the protein. 
A)  The altered tRNA will cause this mRNA to make only nonfunctioning product. 
B)  The tRNA-Leu will not be able to enter the ribosome to bind to the UUA codon. 
C)  One altered tRNA molecule will be relatively inconsequential because it will compete with many "normal" ones. 
D)  The altered tRNA will be so unstable that it will not participate in translation. 
E)  The altered tRNA will result in an amino acid variant in all copies of the protein.

Question 12

Figure 14.5
-Figure 14.5 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?

Accepted Answer

A)  UGG 
B)  GUG 
C)  GUA 
D)  UUC 
E)  CAU 
A)  UGG 
B)  GUG 
C)  GUA 
D)  UUC 
E)  CAU

Question 13

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. The consequence of this for the cell will be that

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. 
E)  none of the options will occur; the cell will recognize the error and destroy the tRNA. 
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. 
E)  none of the options will occur; the cell will recognize the error and destroy the tRNA.

Question 14

Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because

Accepted Answer

A)  metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies. 
B)  enzymes are made of DNA, and affected individuals lack DNA polymerase. 
C)  many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that prevent their enzymes from interacting efficiently with DNA. 
D)  certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors. 
E)  genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes. 
A)  metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies. 
B)  enzymes are made of DNA, and affected individuals lack DNA polymerase. 
C)  many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that prevent their enzymes from interacting efficiently with DNA. 
D)  certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors. 
E)  genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.

Question 15

Which of the following is a function of a poly-A signal sequence?

Accepted Answer

A)  It adds the poly-A tail to the 3' end of the mRNA. 
B)  It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~10-35 nucleotides away. 
C)  It allows the 3' end of the mRNA to attach to the ribosome. 
D)  It is a sequence that codes for the hydrolysis of the RNA polymerase. 
E)  It adds a 7-methylguanosine cap to the 3' end of the mRNA. 
A)  It adds the poly-A tail to the 3' end of the mRNA. 
B)  It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~10-35 nucleotides away. 
C)  It allows the 3' end of the mRNA to attach to the ribosome. 
D)  It is a sequence that codes for the hydrolysis of the RNA polymerase. 
E)  It adds a 7-methylguanosine cap to the 3' end of the mRNA.

Question 16

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the

Accepted Answer

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

Question 17

What is a ribozyme?

Accepted Answer

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

Question 18

Using the following figure, identify a 5' → 3' sequence of nucleotides in the DNA template strand for an mRNA coding for the polypeptide sequence Phe-Pro-Lys.

Accepted Answer

A)  5´-UUUGGGAAA-3' 
B)  5´-GAACCCCTT-3' 
C)  5´-AAAACCTTT-3' 
D)  5´-CTTCGGGAA-3' 
E)  5´-AAACCCUUU-3' 
A)  5´-UUUGGGAAA-3' 
B)  5´-GAACCCCTT-3' 
C)  5´-AAAACCTTT-3' 
D)  5´-CTTCGGGAA-3' 
E)  5´-AAACCCUUU-3'

Question 19

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

Accepted Answer

A)  many noncoding stretches of nucleotides are present in eukaryotic DNA. 
B)  there is redundancy and ambiguity in the genetic code. 
C)  many nucleotides are needed to code for each amino acid. 
D)  nucleotides break off and are lost during the transcription process. 
E)  there are termination exons near the beginning of mRNA. 
A)  many noncoding stretches of nucleotides are present in eukaryotic DNA. 
B)  there is redundancy and ambiguity in the genetic code. 
C)  many nucleotides are needed to code for each amino acid. 
D)  nucleotides break off and are lost during the transcription process. 
E)  there are termination exons near the beginning of mRNA.

Question 20

The following questions refer to the table of codons in Figure 14.2.
   Figure 14.2
-What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'

Accepted Answer

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 
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

Exam 14: Gene Expression: From Gene to Protein

Suppose that an induced mutation removes most of the 5' end of the 5' UTR. What might result?

If a newly made polypeptide is to be secreted from a cell, what must occur before it is secreted?

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is

Use the following model of a eukaryotic transcript to answer the next few questions. 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?

Which of the following is true of transcription in domain Archaea?

The following questions refer to the simple metabolic pathway in Figure 14.1. Figure 14.1 -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 frameshift mutation could result from

When the genome of a particular species is said to include 20,000 protein-coding regions, what does this imply?

The following questions refer to the table of codons in Figure 14.2. Figure 14.2 -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?

Figure 14.5 -Figure 14.5 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 mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. The consequence of this for the cell will be that

Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because

Which of the following is a function of a poly-A signal sequence?

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the

What is a ribozyme?

Using the following figure, identify a 5' → 3' sequence of nucleotides in the DNA template strand for an mRNA coding for the polypeptide sequence Phe-Pro-Lys.

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

The following questions refer to the table of codons in Figure 14.2. Figure 14.2 -What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'

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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