Question 1

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)  There are also additional genes for RNAs other than mRNA. 
D)  The species is highly evolved. 
A)  There are 20,000 genes. 
B)  Each gene codes for one protein. 
C)  There are also additional genes for RNAs other than mRNA. 
D)  The species is highly evolved.

Question 2

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?

Accepted Answer

A)  A gene from an organism can theoretically be expressed by any other organism. 
B)  All organisms have experienced convergent evolution. 
C)  DNA was the first genetic material. 
D)  The same codons in different organisms translate into the different amino acids. 
E)  Different organisms have different numbers of different types of amino acids. 
A)  A gene from an organism can theoretically be expressed by any other organism. 
B)  All organisms have experienced convergent evolution. 
C)  DNA was the first genetic material. 
D)  The same codons in different organisms translate into the different amino acids. 
E)  Different organisms have different numbers of different types of amino acids.

Question 3

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

Accepted Answer

A)  Removal of the 5' UTR has no effect because the exons remain intact. 
B)  Removal of the 5' UTR also removes the 5' cap, so the mRNA may be quickly degraded by hydrolytic enzymes. 
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. 
A)  Removal of the 5' UTR has no effect because the exons remain intact. 
B)  Removal of the 5' UTR also removes the 5' cap, so the mRNA may be quickly degraded by hydrolytic enzymes. 
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.

Question 4

The "universal" genetic code is now known to have exceptions. Evidence for this can be found if which of the following is true?

Accepted Answer

A)  if UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only) 
B)  if one stop codon, such as UGA, is found to have the same effect on translation as another stop codon, such as UAA 
C)  if prokaryotic organisms are able to translate a eukaryotic mRNA and produce the same polypeptide 
D)  if several codons are found to translate to the same amino acid, such as serine 
A)  if UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only) 
B)  if one stop codon, such as UGA, is found to have the same effect on translation as another stop codon, such as UAA 
C)  if prokaryotic organisms are able to translate a eukaryotic mRNA and produce the same polypeptide 
D)  if several codons are found to translate to the same amino acid, such as serine

Question 5

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 6

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?

Accepted Answer

A)  The mRNA would not be transported out of 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 digested by restriction enzymes in the nucleus. 
D)  The molecule is degraded by hydrolytic enzymes because it is no longer protected at the 5' end and the 3' end. 
E)  The molecule attaches to a ribosome and is translated, but more slowly. 
A)  The mRNA would not be transported out of 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 digested by restriction enzymes in the nucleus. 
D)  The molecule is degraded by hydrolytic enzymes because it is no longer protected at the 5' end and the 3' end. 
E)  The molecule attaches to a ribosome and is translated, but more slowly.

Question 7

Which of the following DNA mutations is likely to have the most negative effect on the protein it specifies?

Accepted Answer

A)  a base-pair deletion 
B)  a codon substitution 
C)  a substitution in the last base of a codon 
D)  a codon deletion 
A)  a base-pair deletion 
B)  a codon substitution 
C)  a substitution in the last base of a codon 
D)  a codon deletion

Question 8

RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are the same for the transcription of any gene, but one, known as sigma, varies considerably. Which of the following is the most probable advantage for the organism in having such variability in RNA polymerase?

Accepted Answer

A)  It might allow the translation process to vary from one cell to another. 
B)  It might allow the polymerase to recognize different promoters under certain environmental conditions. 
C)  It might allow the polymerase to react differently to each stop codon. 
D)  It might alter the rate of translation and of exon splicing. 
A)  It might allow the translation process to vary from one cell to another. 
B)  It might allow the polymerase to recognize different promoters under certain environmental conditions. 
C)  It might allow the polymerase to react differently to each stop codon. 
D)  It might alter the rate of translation and of exon splicing.

Question 9

Which of the following mutations would be most likely to have a harmful effect on an organism?

Accepted Answer

A)  a deletion of three nucleotides near the middle of a gene 
B)  a single nucleotide deletion in the middle of an intron 
C)  a single nucleotide deletion near the end of the coding sequence 
D)  a single nucleotide insertion downstream of, and close to, the start of the coding sequence 
A)  a deletion of three nucleotides near the middle of a gene 
B)  a single nucleotide deletion in the middle of an intron 
C)  a single nucleotide deletion near the end of the coding sequence 
D)  a single nucleotide insertion downstream of, and close to, the start of the coding sequence

Question 10

In comparing DNA replication with RNA transcription in the same cell, which of the following is true only of replication?

Accepted Answer

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. 
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.

Question 11

When the spliceosome binds to a pre-mRNA transcript, where does it typically attach?

Accepted Answer

A)  to the exons 
B)  to the 5' UTR 
C)  to the 3' UTR 
D)  at certain sequences along an intron 
A)  to the exons 
B)  to the 5' UTR 
C)  to the 3' UTR 
D)  at certain sequences along an intron

Question 12

During splicing, which molecular component of the spliceosome catalyzes the excision reaction?

Accepted Answer

A)  protein 
B)  DNA 
C)  RNA 
D)  lipid 
E)  sugar 
A)  protein 
B)  DNA 
C)  RNA 
D)  lipid 
E)  sugar

Question 13

Which of the following statements best describes the termination of transcription in prokaryotes?

Accepted Answer

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

Question 14

In what way might a point mutation in DNA make a difference in the function of a protein?

Accepted Answer

A)  It might result in a chromosomal translocation. 
B)  It might exchange one stop codon for another stop codon. 
C)  It might exchange one serine codon for a different serine codon. 
D)  It might substitute a different amino acid in the active site. 
E)  It might substitute the N-terminus of the polypeptide for the C-terminus. 
A)  It might result in a chromosomal translocation. 
B)  It might exchange one stop codon for another stop codon. 
C)  It might exchange one serine codon for a different serine codon. 
D)  It might substitute a different amino acid in the active site. 
E)  It might substitute the N-terminus of the polypeptide for the C-terminus.

Question 15

Transcription in eukaryotes requires which of the following in addition to RNA polymerase?

Accepted Answer

A)  the protein product of the promoter 
B)  start and stop codons 
C)  ribosomes and tRNA 
D)  several transcription factors 
E)  aminoacyl-tRNA synthetase 
A)  the protein product of the promoter 
B)  start and stop codons 
C)  ribosomes and tRNA 
D)  several transcription factors 
E)  aminoacyl-tRNA synthetase

Question 16

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 dipeptide that will form will be

Accepted Answer

A)  cysteine-alanine. 
B)  proline-threonine. 
C)  glycine-cysteine. 
D)  alanine-alanine. 
E)  threonine-glycine. 
A)  cysteine-alanine. 
B)  proline-threonine. 
C)  glycine-cysteine. 
D)  alanine-alanine. 
E)  threonine-glycine.

Question 17

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 the amino acid leucine, Leu). What will be the effect on the translation of polypeptides 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 have little effect because it will compete with many "normal" ones. 
D)  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 have little effect because it will compete with many "normal" ones. 
D)  The altered tRNA will result in an amino acid variant in all copies of the protein.

Question 18

Please use the following information to answer the question(s) below.
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) already in the ribosome.
-Which component of the complex described enters the exit tunnel through the large subunit of the ribosome?

Accepted Answer

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 
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

Question 19

Please use the following information to answer the question(s) below.
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) already in the ribosome.
-Where does tRNA #2 move to after this bonding of lysine to the polypeptide?

Accepted Answer

A)  A site 
B)  P site 
C)  E site 
D)  exit tunnel 
E)  directly to the cytosol 
A)  A site 
B)  P site 
C)  E site 
D)  exit tunnel 
E)  directly to the cytosol

Question 20

Figure 14.1
-Examine the simple metabolic pathway in Figure 14.1. According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
E)  It cannot be determined from the pathway. 
A)  0 
B)  1 
C)  2 
D)  3 
E)  It cannot be determined from the pathway.

Exam 14: Gene Expression: From Gene to Protein

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

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?

The "universal" genetic code is now known to have exceptions. Evidence for this can be found if which of the following is true?

What is a ribozyme?

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?

Which of the following DNA mutations is likely to have the most negative effect on the protein it specifies?

RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are the same for the transcription of any gene, but one, known as sigma, varies considerably. Which of the following is the most probable advantage for the organism in having such variability in RNA polymerase?

Which of the following mutations would be most likely to have a harmful effect on an organism?

In comparing DNA replication with RNA transcription in the same cell, which of the following is true only of replication?

When the spliceosome binds to a pre-mRNA transcript, where does it typically attach?

During splicing, which molecular component of the spliceosome catalyzes the excision reaction?

Which of the following statements best describes the termination of transcription in prokaryotes?

In what way might a point mutation in DNA make a difference in the function of a protein?

Transcription in eukaryotes requires which of the following in addition to RNA polymerase?

Figure 14.1 -Examine the simple metabolic pathway in Figure 14.1. According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?

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

Filters