Question 1

A lack of which molecule would result in the cell's inability to "turn off" genes?

Accepted Answer

A)  operon 
B)  inducer 
C)  promoter 
D)  ubiquitin 
E)  corepressor 
A)  operon 
B)  inducer 
C)  promoter 
D)  ubiquitin 
E)  corepressor

Question 2

Epstein Bar Virus (EBV) causes most of us to have an episode of sore throat and swollen glands during early childhood. If we first become exposed to the virus during our teen years, however, EBV causes the syndrome we know as mononucleosis. However, in special circumstances, the same virus can be carcinogenic.
-In a different part of the world, namely in parts of southeast Asia, the same virus is associated with a different kind of cancer of the throat. Which of the following is most probable?

Accepted Answer

A)  Viral infection is correlated with a different immunological reaction. 
B)  The virus infects the people via different routes. 
C)  The virus only infects the elderly. 
D)  The virus mutates more frequently in the Asian population. 
E)  Malaria is also found in this region. 
A)  Viral infection is correlated with a different immunological reaction. 
B)  The virus infects the people via different routes. 
C)  The virus only infects the elderly. 
D)  The virus mutates more frequently in the Asian population. 
E)  Malaria is also found in this region.

Question 3

One hereditary disease in humans, called xeroderma pigmentosum (XP), makes homozygous individuals exceptionally susceptible to UV-induced mutation damage in the cells of exposed tissue, especially skin. Without extraordinary avoidance of sunlight exposure, patients soon succumb to numerous skin cancers.
-Given the damage caused by UV, the kind of gene affected in those with XP is one whose product is involved with

Accepted Answer

A)  mending of double-strand breaks in the DNA backbone. 
B)  breakage of cross-strand covalent bonds. 
C)  the ability to excise single-strand damage and replace it. 
D)  the removal of double-strand damaged areas. 
E)  causing affected skin cells to undergo apoptosis. 
A)  mending of double-strand breaks in the DNA backbone. 
B)  breakage of cross-strand covalent bonds. 
C)  the ability to excise single-strand damage and replace it. 
D)  the removal of double-strand damaged areas. 
E)  causing affected skin cells to undergo apoptosis.

Question 4

Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following?

Accepted Answer

A)  Eukaryotic mRNAs get 5' caps and 3' tails. 
B)  Prokaryotic genes are expressed as mRNA, which is more stable in the cell. 
C)  Eukaryotic exons may be spliced in alternative patterns. 
D)  Prokaryotes use ribosomes of different structure and size. 
E)  Eukaryotic coded polypeptides often require cleaving of signal sequences before localization. 
A)  Eukaryotic mRNAs get 5' caps and 3' tails. 
B)  Prokaryotic genes are expressed as mRNA, which is more stable in the cell. 
C)  Eukaryotic exons may be spliced in alternative patterns. 
D)  Prokaryotes use ribosomes of different structure and size. 
E)  Eukaryotic coded polypeptides often require cleaving of signal sequences before localization.

Question 5

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 6

What is considered to be the first evidence of differentiation in the cells of an embryo?

Accepted Answer

A)  cell division occurring after fertilization 
B)  the occurrence of mRNAs for the production of tissue-specific proteins 
C)  determination of specific cells for certain functions 
D)  changes in the size and shape of the cell 
E)  changes resulting from induction 
A)  cell division occurring after fertilization 
B)  the occurrence of mRNAs for the production of tissue-specific proteins 
C)  determination of specific cells for certain functions 
D)  changes in the size and shape of the cell 
E)  changes resulting from induction

Question 7

If a Drosophila female has a homozygous mutation for a maternal effect gene,

Accepted Answer

A)  she will not develop past the early embryonic stage. 
B)  all of her offspring will show the mutant phenotype, regardless of their genotype. 
C)  only her male offspring will show the mutant phenotype. 
D)  her offspring will show the mutant phenotype only if they are also homozygous for the mutation. 
E)  only her female offspring will show the mutant phenotype. 
A)  she will not develop past the early embryonic stage. 
B)  all of her offspring will show the mutant phenotype, regardless of their genotype. 
C)  only her male offspring will show the mutant phenotype. 
D)  her offspring will show the mutant phenotype only if they are also homozygous for the mutation. 
E)  only her female offspring will show the mutant phenotype.

Question 8

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 9

Use the following information to answer the following questions.
In Drosophila after ~100 minutes postfertilization, the embryo looks like the following diagram, with all nuclei having moved to the periphery and, subsequently, four of the nuclei being sequestered at the posterior end.
   
Drosophila embryo after about 2 hours.
-At this point, the embryo is characterized as

Accepted Answer

A)  a first-stage larva. 
B)  nuclei in the cortex that has not undergone cytokinesis. 
C)  nuclei in the cortex forming a single-cell layer over the surface. 
D)  an embryo with segmentation beginning to be apparent. 
A)  a first-stage larva. 
B)  nuclei in the cortex that has not undergone cytokinesis. 
C)  nuclei in the cortex forming a single-cell layer over the surface. 
D)  an embryo with segmentation beginning to be apparent.

Question 10

Steroid hormones produce their effects in cells by

Accepted Answer

A)  activating key enzymes in metabolic pathways. 
B)  activating translation of certain mRNAs. 
C)  promoting the degradation of specific mRNAs. 
D)  binding to intracellular receptors and promoting transcription of specific genes. 
E)  promoting the formation of looped domains in certain regions of DNA. 
A)  activating key enzymes in metabolic pathways. 
B)  activating translation of certain mRNAs. 
C)  promoting the degradation of specific mRNAs. 
D)  binding to intracellular receptors and promoting transcription of specific genes. 
E)  promoting the formation of looped domains in certain regions of DNA.

Question 11

The tryptophan operon is a repressible operon that is

Accepted Answer

A)  permanently turned on. 
B)  turned on only when tryptophan is present in the growth medium. 
C)  turned off only when glucose is present in the growth medium. 
D)  turned on only when glucose is present in the growth medium. 
E)  turned off whenever tryptophan is added to the growth medium. 
A)  permanently turned on. 
B)  turned on only when tryptophan is present in the growth medium. 
C)  turned off only when glucose is present in the growth medium. 
D)  turned on only when glucose is present in the growth medium. 
E)  turned off whenever tryptophan is added to the growth medium.

Question 12

If glucose is available in the environment of E. coli, the cell responds with a very low concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of the following would you expect to be a measurable effect?

Accepted Answer

A)  decreased concentration of the lac enzymes 
B)  increased concentration of the trp enzymes 
C)  decreased binding of the RNA polymerase to sugar metabolism-related promoters 
D)  decreased concentration of alternative sugars in the cell 
E)  increased concentrations of sugars such as arabinose in the cell 
A)  decreased concentration of the lac enzymes 
B)  increased concentration of the trp enzymes 
C)  decreased binding of the RNA polymerase to sugar metabolism-related promoters 
D)  decreased concentration of alternative sugars in the cell 
E)  increased concentrations of sugars such as arabinose in the cell

Question 13

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.

Question 14

The fact that plants can be cloned from somatic cells demonstrates that

Accepted Answer

A)  differentiated cells retain all the genes of the zygote. 
B)  genes are lost during differentiation. 
C)  the differentiated state is normally very unstable. 
D)  differentiated cells contain masked mRNA. 
E)  differentiation does not occur in plants. 
A)  differentiated cells retain all the genes of the zygote. 
B)  genes are lost during differentiation. 
C)  the differentiated state is normally very unstable. 
D)  differentiated cells contain masked mRNA. 
E)  differentiation does not occur in plants.

Question 15

What must characterize the XLP population?

Accepted Answer

A)  They must have severe immunological problems starting at birth. 
B)  They must all be males with affected male relatives. 
C)  They must all be males with affected female relatives. 
D)  They must all inherit this syndrome from their fathers. 
E)  They must live in sub-Saharan Africa. 
A)  They must have severe immunological problems starting at birth. 
B)  They must all be males with affected male relatives. 
C)  They must all be males with affected female relatives. 
D)  They must all inherit this syndrome from their fathers. 
E)  They must live in sub-Saharan Africa.

Question 16

A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture.
-One of her colleagues suggested she try increased methylation of C nucleotides in a mammalian system. Which of the following results would she most likely see?

Accepted Answer

A)  increased chromatin condensation 
B)  decreased chromatin condensation 
C)  abnormalities of mouse embryos 
D)  decreased binding of transcription factors 
E)  inactivation of the selected genes 
A)  increased chromatin condensation 
B)  decreased chromatin condensation 
C)  abnormalities of mouse embryos 
D)  decreased binding of transcription factors 
E)  inactivation of the selected genes

Question 17

Epstein Bar Virus (EBV) causes most of us to have an episode of sore throat and swollen glands during early childhood. If we first become exposed to the virus during our teen years, however, EBV causes the syndrome we know as mononucleosis. However, in special circumstances, the same virus can be carcinogenic.
-A very rare human allele of a gene called XLP, or X-linked lymphoproliferative syndrome, causes a small number of people from many different parts of the world to get cancer following even childhood exposure to EBV. Given the previous information, what might be going on?

Accepted Answer

A)  The people must have previously had malaria. 
B)  Their ancestors must be from sub-Saharan Africa or southeast Asia. 
C)  They must be unable to mount an immune response to EBV. 
D)  They must have severe combined immune deficiency (SCI
D) . 
E)  Their whole immune system must be overreplicating. 
A)  The people must have previously had malaria. 
B)  Their ancestors must be from sub-Saharan Africa or southeast Asia. 
C)  They must be unable to mount an immune response to EBV. 
D)  They must have severe combined immune deficiency (SCI
D) . 
E)  Their whole immune system must be overreplicating.

Question 18

Which of the following is most likely to have a small protein called ubiquitin attached to it?

Accepted Answer

A)  a cyclin that usually acts in G₁, now that the cell is in G₂ 
B)  a cell surface protein that requires transport from the ER 
C)  an mRNA that is leaving the nucleus to be translated 
D)  a regulatory protein that requires sugar residues to be attached 
E)  an mRNA produced by an egg cell that will be retained until after fertilization 
A)  a cyclin that usually acts in G₁, now that the cell is in G₂ 
B)  a cell surface protein that requires transport from the ER 
C)  an mRNA that is leaving the nucleus to be translated 
D)  a regulatory protein that requires sugar residues to be attached 
E)  an mRNA produced by an egg cell that will be retained until after fertilization

Question 19

Two potential devices that eukaryotic cells use to regulate transcription are

Accepted Answer

A)  DNA methylation and histone amplification. 
B)  DNA amplification and histone methylation. 
C)  DNA acetylation and methylation. 
D)  DNA methylation and histone modification. 
E)  histone amplification and DNA acetylation. 
A)  DNA methylation and histone amplification. 
B)  DNA amplification and histone methylation. 
C)  DNA acetylation and methylation. 
D)  DNA methylation and histone modification. 
E)  histone amplification and DNA acetylation.

Question 20

A few decades ago, Knudsen and colleagues proposed a theory that, for a normal cell to become a cancer cell, a minimum of two genetic changes had to occur in that cell. Knudsen was studying retinoblastoma, a childhood cancer of the eye.
-Knudsen and colleagues also noted that persons with hereditary retinoblastoma that had been treated successfully lived on but then had a higher frequency of developing osteosarcomas (bone cancers)later in life. This provided further evidence of their theory because

Accepted Answer

A)  osteosarcoma cells express the same genes as retinal cells. 
B)  p53 gene mutations are common to both tumors. 
C)  both kinds of cancer involve overproliferation of cells. 
D)  one of the mutations involved in retinoblastoma is also one of the changes involved in osteosarcoma. 
E)  retinoblastoma is a prerequisite for the formation of osteosarcoma later in life. 
A)  osteosarcoma cells express the same genes as retinal cells. 
B)  p53 gene mutations are common to both tumors. 
C)  both kinds of cancer involve overproliferation of cells. 
D)  one of the mutations involved in retinoblastoma is also one of the changes involved in osteosarcoma. 
E)  retinoblastoma is a prerequisite for the formation of osteosarcoma later in life.

Exam 18: Regulation of Gene Expression

A lack of which molecule would result in the cell's inability to "turn off" genes?

Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following?

Cell differentiation always involves

What is considered to be the first evidence of differentiation in the cells of an embryo?

If a Drosophila female has a homozygous mutation for a maternal effect gene,

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

Steroid hormones produce their effects in cells by

The tryptophan operon is a repressible operon that is

If glucose is available in the environment of E. coli, the cell responds with a very low concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of the following would you expect to be a measurable effect?

Muscle cells differ from nerve cells mainly because they

The fact that plants can be cloned from somatic cells demonstrates that

What must characterize the XLP population?

A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. -One of her colleagues suggested she try increased methylation of C nucleotides in a mammalian system. Which of the following results would she most likely see?

Which of the following is most likely to have a small protein called ubiquitin attached to it?

Two potential devices that eukaryotic cells use to regulate transcription are

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Viruses

Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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