Question 1

Which of the following is TRUE?

Accepted Answer

A)  Mutations that inactivate tumor suppressor genes are important in cancer. 
B)  Cancer is a single disease with one underlying molecular cause. 
C)  Uncontrolled cell growth alone is sufficient for the development of cancers. 
D)  Cancer is a single disease resulting from a common set of mutations. 
A)  Mutations that inactivate tumor suppressor genes are important in cancer. 
B)  Cancer is a single disease with one underlying molecular cause. 
C)  Uncontrolled cell growth alone is sufficient for the development of cancers. 
D)  Cancer is a single disease resulting from a common set of mutations. A

Question 2

Which of the following is most critical for the association between histones and DNA?

Accepted Answer

A)  Histones are small proteins. 
B)  Histones are highly conserved (that is, histones are very similar in every eukaryote). 
C)  Histones are synthesized in the cytoplasm. 
D)  There are at least five different histone proteins in every eukaryote. 
E)  Histones are positively charged. 
A)  Histones are small proteins. 
B)  Histones are highly conserved (that is, histones are very similar in every eukaryote). 
C)  Histones are synthesized in the cytoplasm. 
D)  There are at least five different histone proteins in every eukaryote. 
E)  Histones are positively charged. E

Question 3

The functioning of enhancers is an example of ________.

Accepted Answer

A)  transcriptional control of gene expression 
B)  a post-transcriptional mechanism to regulate mRNA 
C)  the stimulation of translation by initiation factors 
D)  post-translational control that activates certain proteins 
E)  a eukaryotic equivalent of prokaryotic promoter functioning 
A)  transcriptional control of gene expression 
B)  a post-transcriptional mechanism to regulate mRNA 
C)  the stimulation of translation by initiation factors 
D)  post-translational control that activates certain proteins 
E)  a eukaryotic equivalent of prokaryotic promoter functioning A

Question 4

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

Accepted Answer

A)  Proto-oncogenes first arose from viral infections. 
B)  Proto-oncogenes normally help regulate cell division. 
C)  Proto-oncogenes are genetic "junk." 
D)  Proto-oncogenes are mutant versions of normal genes. 
E)  Cells produce proto-oncogenes as they age. 
A)  Proto-oncogenes first arose from viral infections. 
B)  Proto-oncogenes normally help regulate cell division. 
C)  Proto-oncogenes are genetic "junk." 
D)  Proto-oncogenes are mutant versions of normal genes. 
E)  Cells produce proto-oncogenes as they age.

Question 5

Which of the following statements about the DNA in one of your brain cells is TRUE?

Accepted Answer

A)  Most of the DNA codes for protein. 
B)  All of the genes of the genome are likely to be transcribed. 
C)  Each gene lies immediately adjacent to an enhancer. 
D)  Many related genes are transcribed from a single promoter. 
E)  It is the same as the DNA in one of your heart cells. 
A)  Most of the DNA codes for protein. 
B)  All of the genes of the genome are likely to be transcribed. 
C)  Each gene lies immediately adjacent to an enhancer. 
D)  Many related genes are transcribed from a single promoter. 
E)  It is the same as the DNA in one of your heart cells.

Question 6

Proto-oncogenes ________.

Accepted Answer

A)  normally suppress tumor growth 
B)  were initially introduced into eukaryotic cells by retroviruses 
C)  are produced by somatic mutations induced by carcinogenic substances 
D)  stimulate normal cell growth and division 
E)  are underexpressed in cancer cells 
A)  normally suppress tumor growth 
B)  were initially introduced into eukaryotic cells by retroviruses 
C)  are produced by somatic mutations induced by carcinogenic substances 
D)  stimulate normal cell growth and division 
E)  are underexpressed in cancer cells

Question 7

Cell differentiation always involves ________.

Accepted Answer

A)  the production of tissue-specific proteins, such as muscle actin 
B)  the movement of cells 
C)  the transcription of the myoD gene 
D)  the selective loss of certain genes from the genome 
E)  the cell's sensitivity to environmental cues, such as light or heat 
A)  the production of tissue-specific proteins, such as muscle actin 
B)  the movement of cells 
C)  the transcription of the myoD gene 
D)  the selective loss of certain genes from the genome 
E)  the cell's sensitivity to environmental cues, such as light or heat

Question 8

Which of the following is an example of post-transcriptional control of gene expression?

Accepted Answer

A)  the addition of methyl groups to cytosine bases of DNA 
B)  the binding of transcription factors to a promoter 
C)  the removal of introns and alternative splicing of exons 
D)  gene amplification contributing to cancer 
E)  the folding of DNA to form heterochromatin 
A)  the addition of methyl groups to cytosine bases of DNA 
B)  the binding of transcription factors to a promoter 
C)  the removal of introns and alternative splicing of exons 
D)  gene amplification contributing to cancer 
E)  the folding of DNA to form heterochromatin

Question 9

Tumor-suppressor genes ________.

Accepted Answer

A)  are frequently overexpressed in cancerous cells 
B)  are cancer-causing genes introduced into cells by viruses 
C)  encode proteins that help prevent uncontrolled cell growth 
D)  often encode proteins that stimulate the cell cycle 
A)  are frequently overexpressed in cancerous cells 
B)  are cancer-causing genes introduced into cells by viruses 
C)  encode proteins that help prevent uncontrolled cell growth 
D)  often encode proteins that stimulate the cell cycle

Question 10

The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called ________.

Accepted Answer

A)  RNA interference 
B)  RNA obstruction 
C)  RNA blocking 
D)  RNA targeting 
E)  RNA disposal 
A)  RNA interference 
B)  RNA obstruction 
C)  RNA blocking 
D)  RNA targeting 
E)  RNA disposal

Question 11

Poliovirus is an RNA virus of the picornavirus group, which uses its RNA as mRNA. At its 5' end, the RNA genome has a viral protein (VPg) instead of a 5' cap. This is followed by a nontranslated leader sequence and then a single long protein-coding region (~7000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acid analogues. Short-period use of the radioactive amino acids result in labeling of only very long proteins, while longer periods of labeling result in several different short polypeptides. What conclusion is most consistent with the results of the radioactive labeling experiment?

Accepted Answer

A)  Host cell ribosomes only translate the viral code into short polypeptides. 
B)  The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones. 
C)  The RNA is translated into short polypeptides, which are subsequently assembled into large ones. 
D)  The large radioactive polypeptides are coded by the host, whereas the short ones are coded for by the virus. 
A)  Host cell ribosomes only translate the viral code into short polypeptides. 
B)  The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones. 
C)  The RNA is translated into short polypeptides, which are subsequently assembled into large ones. 
D)  The large radioactive polypeptides are coded by the host, whereas the short ones are coded for by the virus.

Question 12

Use this information to answer the question(s) below.
-One of her colleagues suggested she try increased methylation of C nucleotides in the DNA of promoters of a mammalian system. Which of the following results would she most likely see?

Accepted Answer

A)  decreased chromatin condensation 
B)  activation of histone tails for enzymatic function 
C)  higher levels of transcription of certain genes 
D)  inactivation of the selected genes 
A)  decreased chromatin condensation 
B)  activation of histone tails for enzymatic function 
C)  higher levels of transcription of certain genes 
D)  inactivation of the selected genes

Question 13

Which of the following statements is TRUE of histones?

Accepted Answer

A)  Each nucleosome consists of two molecules of histone H1. 
B)  Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together. 
C)  The carboxyl end of each histone extends outward from the nucleosome and is called a "histone tail." 
D)  Histones are found in mammals but not in other animals or in plants or fungi. 
A)  Each nucleosome consists of two molecules of histone H1. 
B)  Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together. 
C)  The carboxyl end of each histone extends outward from the nucleosome and is called a "histone tail." 
D)  Histones are found in mammals but not in other animals or in plants or fungi.

Question 14

Imagine that you are studying the control of β-globin gene expression in immature red blood cells. (Mature red blood cells contain β-globin protein but lack a nucleus and, therefore, the β-globin gene.) If you deleted a sequence of DNA outside the protein-coding region of the β-globin gene and found that this increased the rate of transcription, the deleted sequence likely functions as ________.

Accepted Answer

A)  a promoter 
B)  a promoter-proximal element 
C)  an enhancer 
D)  a silencer 
E)  any of the listed functions 
A)  a promoter 
B)  a promoter-proximal element 
C)  an enhancer 
D)  a silencer 
E)  any of the listed functions

Question 15

If cells of an individual contain the same set of genes, how do these cells become different from each other during development?

Accepted Answer

A)  Different cell type-specific regulatory elements in DNA are created during development. 
B)  Different cell type-specific regulatory elements in DNA are selectively lost during development. 
C)  Differences in extracellular signals received by each cell lead to differences in the types of regulatory proteins present in each cell. 
D)  Differences develop in promoter sequences that lead to different signals being produced by each type of cell. 
A)  Different cell type-specific regulatory elements in DNA are created during development. 
B)  Different cell type-specific regulatory elements in DNA are selectively lost during development. 
C)  Differences in extracellular signals received by each cell lead to differences in the types of regulatory proteins present in each cell. 
D)  Differences develop in promoter sequences that lead to different signals being produced by each type of cell.

Question 16

An example of a basal transcription factor is ________.

Accepted Answer

A)  RNA polymerase 
B)  the TATA-binding protein 
C)  an enhancer-binding transcription factor 
D)  a silencer-binding transcription factor 
E)  a promoter-proximal-binding transcription factor 
A)  RNA polymerase 
B)  the TATA-binding protein 
C)  an enhancer-binding transcription factor 
D)  a silencer-binding transcription factor 
E)  a promoter-proximal-binding transcription factor

Question 17

Which method is utilized by eukaryotes to control their gene expression that is NOT used in bacteria?

Accepted Answer

A)  control of chromatin remodeling 
B)  control of RNA splicing 
C)  transcriptional control 
D)  control of both RNA splicing and chromatin remodeling 
E)  control of chromatin remodeling, RNA splicing, and transcription 
A)  control of chromatin remodeling 
B)  control of RNA splicing 
C)  transcriptional control 
D)  control of both RNA splicing and chromatin remodeling 
E)  control of chromatin remodeling, RNA splicing, and transcription

Question 18

Of the following, which is the most current 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 19

In a nucleosome, the DNA is wrapped around ________.

Accepted Answer

A)  polymerase molecules 
B)  ribosomes 
C)  histones 
D)  a thymine dimer 
E)  satellite DNA 
A)  polymerase molecules 
B)  ribosomes 
C)  histones 
D)  a thymine dimer 
E)  satellite DNA

Question 20

Muscle cells differ from nerve cells mainly because they ________.

Accepted Answer

A)  express different genes 
B)  contain different genes 
C)  use different genetic codes 
D)  have unique ribosomes 
E)  have different chromosomes 
A)  express different genes 
B)  contain different genes 
C)  use different genetic codes 
D)  have unique ribosomes 
E)  have different chromosomes

Exam 19: Control of Gene Expression in Eukaryotes

Which of the following is TRUE?

Which of the following is most critical for the association between histones and DNA?

The functioning of enhancers is an example of ________.

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

Which of the following statements about the DNA in one of your brain cells is TRUE?

Proto-oncogenes ________.

Cell differentiation always involves ________.

Which of the following is an example of post-transcriptional control of gene expression?

Tumor-suppressor genes ________.

The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called ________.

Use this information to answer the question(s) below. -One of her colleagues suggested she try increased methylation of C nucleotides in the DNA of promoters of a mammalian system. Which of the following results would she most likely see?

Which of the following statements is TRUE of histones?

If cells of an individual contain the same set of genes, how do these cells become different from each other during development?

An example of a basal transcription factor is ________.

Which method is utilized by eukaryotes to control their gene expression that is NOT used in bacteria?

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

In a nucleosome, the DNA is wrapped around ________.

Muscle cells differ from nerve cells mainly because they ________.

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Ecosystems and Global Ecology

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes: an Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cellcell Interactions

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

The Molecular Revolution: Biotechnology and Beyond

Genes, Development, and Evolution

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioral Ecology

Population Ecology

Community Ecology

Biodiversity and Conservation Biology

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