Question 1

The term epigenetics refers to

Accepted Answer

A) inheritance of traits by mechanisms not involving changes in nucleotide sequence. 
B) inheritance of traits which involve changes in nucleotide sequence. 
C) phenotypic expression as a result of changes in nucleotide sequence. 
D) phenotypic expression in the next generation as a result of mutations in the parent. 
E) the silencing of genes through miRNA function. 
A) inheritance of traits by mechanisms not involving changes in nucleotide sequence. 
B) inheritance of traits which involve changes in nucleotide sequence. 
C) phenotypic expression as a result of changes in nucleotide sequence. 
D) phenotypic expression in the next generation as a result of mutations in the parent. 
E) the silencing of genes through miRNA function.

Question 2

In eukaryotes,general transcription factors

Accepted Answer

A) are required for the expression of specific protein-encoding genes. 
B) bind to other proteins or to a sequence element within the promoter called the TATA box. 
C) inhibit RNA polymerase binding to the promoter and begin transcribing. 
D) usually lead to a high level of transcription even without additional specific transcription factors. 
E) bind to sequences just after the start site of transcription. 
A) are required for the expression of specific protein-encoding genes. 
B) bind to other proteins or to a sequence element within the promoter called the TATA box. 
C) inhibit RNA polymerase binding to the promoter and begin transcribing. 
D) usually lead to a high level of transcription even without additional specific transcription factors. 
E) bind to sequences just after the start site of transcription.

Question 3

How does extracellular glucose inhibits transcription of the lac operon?

Accepted Answer

A) by strengthening the binding of the repressor to the operator 
B) by weakening the binding of the repressor to the operator 
C) by inhibiting RNA polymerase from opening the strands of DNA to initiate transcription 
D) by reducing the levels of intracellular cAMP 
E) by binding to CAP 
A) by strengthening the binding of the repressor to the operator 
B) by weakening the binding of the repressor to the operator 
C) by inhibiting RNA polymerase from opening the strands of DNA to initiate transcription 
D) by reducing the levels of intracellular cAMP 
E) by binding to CAP

Question 4

Why is the number of protein-coding genes not equivalent to the number of proteins produced in any given eukaryotic species?

Accepted Answer

A) chromatin condensation control 
B) transcriptional control 
C) alternative splicing 
D) translational control 
E) repression of promoters 
A) chromatin condensation control 
B) transcriptional control 
C) alternative splicing 
D) translational control 
E) repression of promoters

Question 5

Transcription factors in eukaryotes usually have DNA binding domains as well as other domains that are also specific for binding.In general,which of the following would you expect many of them to be able to bind?

Accepted Answer

A) repressors 
B) ATP 
C) protein-based hormones 
D) other transcription factors 
E) tRNA 
A) repressors 
B) ATP 
C) protein-based hormones 
D) other transcription factors 
E) tRNA

Question 6

The lactose operon is likely to be transcribed when

Accepted Answer

A) there is more glucose in the cell than lactose. 
B) the cyclic AMP levels are low. 
C) there is glucose but no lactose in the cell. 
D) the cyclic AMP and lactose levels are both high within the cell. 
E) the cAMP level is high and the lactose level is low. 
A) there is more glucose in the cell than lactose. 
B) the cyclic AMP levels are low. 
C) there is glucose but no lactose in the cell. 
D) the cyclic AMP and lactose levels are both high within the cell. 
E) the cAMP level is high and the lactose level is low.

Question 7

Which of the following best describes siRNA?

Accepted Answer

A) a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA 
B) a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns 
C) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor 
D) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits 
E) a molecule, known as Dicer, that can degrade other mRNA sequences 
A) a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA 
B) a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns 
C) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor 
D) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits 
E) a molecule, known as Dicer, that can degrade other mRNA sequences

Question 8

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.

Question 9

Use the following figure to answer the questions below.
  
-What does D represent?

Accepted Answer

A) promoter sequences 
B) exons 
C) introns 
D) transcription factors 
E) mRNA 
A) promoter sequences 
B) exons 
C) introns 
D) transcription factors 
E) mRNA

Question 10

Which of the following describes the function of an enzyme known as Dicer?

Accepted Answer

A) It degrades single-stranded DNA. 
B) It degrades single-stranded mRNA. 
C) It degrades mRNA with no poly-A tail. 
D) It trims small double-stranded RNAs into molecules that can block translation or help degrade mRNA. 
E) It chops up single-stranded DNAs from infecting viruses. 
A) It degrades single-stranded DNA. 
B) It degrades single-stranded mRNA. 
C) It degrades mRNA with no poly-A tail. 
D) It trims small double-stranded RNAs into molecules that can block translation or help degrade mRNA. 
E) It chops up single-stranded DNAs from infecting viruses.

Question 11

Drosophila larvae (wt)showing segmentation and anterior-posterior axis.
Refer to the image above to answer the following questions.
-What would happen if the larvae developed a mutation in the bicoid gene?

Accepted Answer

A) Nothing. 
B) The larvae would have two heads. 
C) The larvae would have two tails. 
D) The larvae would be an embryonic lethal. 
E) The larvae would develop normally, but its offspring would be embryonic lethal. 
A) Nothing. 
B) The larvae would have two heads. 
C) The larvae would have two tails. 
D) The larvae would be an embryonic lethal. 
E) The larvae would develop normally, but its offspring would be embryonic lethal.

Question 12

During DNA replication

Accepted Answer

A) all methylation of the DNA is lost at the first round of replication. 
B) DNA polymerase is blocked by methyl groups, and methylated regions of the genome are therefore left uncopied. 
C) methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylates daughter strands after replication. 
D) methylation of the DNA is maintained because DNA polymerase directly incorporates methylated nucleotides into the new strand opposite any methylated nucleotides in the template. 
E) methylated DNA is copied in the cytoplasm, and unmethylated DNA is copied in the nucleus. 
A) all methylation of the DNA is lost at the first round of replication. 
B) DNA polymerase is blocked by methyl groups, and methylated regions of the genome are therefore left uncopied. 
C) methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylates daughter strands after replication. 
D) methylation of the DNA is maintained because DNA polymerase directly incorporates methylated nucleotides into the new strand opposite any methylated nucleotides in the template. 
E) methylated DNA is copied in the cytoplasm, and unmethylated DNA is copied in the nucleus.

Question 13

Use the following information to answer the questions below.
A researcher has arrived at a method to prevent gene expression from Drosophila embryonic genes.The following questions assume that he is using this method.
-Which of the following are maternal effect genes that control the orientation of the egg and thus the Drosophila embryo?

Accepted Answer

A) homeotic genes 
B) segmentation genes 
C) egg-polarity genes 
D) morphogens 
E) enhancer genes 
A) homeotic genes 
B) segmentation genes 
C) egg-polarity genes 
D) morphogens 
E) enhancer genes

Question 14

Which of the following types of RNA are involved in RNAi?

Accepted Answer

A) mRNA 
B) miRNA 
C) tRNA 
D) ssRNA 
E) xRNA 
A) mRNA 
B) miRNA 
C) tRNA 
D) ssRNA 
E) xRNA

Question 15

Use the following information to answer the questions below.
Epstein Barr 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 areas of the world where malaria is endemic,notably in sub-Saharan Africa,EBV can cause Burkitt's lymphoma in children,which is usually associated with large tumours of the jaw.Which of the following is consistent with these findings?

Accepted Answer

A) EBV infection makes the malarial parasite able to produce lymphoma. 
B) Malaria's strain on the immune system makes EBV infection worse. 
C) Malaria occurs more frequently in those infected with EBV. 
D) Malarial response of the immune system prevents an individual from making EBV antibodies. 
E) A cell infected with the malarial parasite is more resistant to the virus. 
A) EBV infection makes the malarial parasite able to produce lymphoma. 
B) Malaria's strain on the immune system makes EBV infection worse. 
C) Malaria occurs more frequently in those infected with EBV. 
D) Malarial response of the immune system prevents an individual from making EBV antibodies. 
E) A cell infected with the malarial parasite is more resistant to the virus.

Question 16

Use the following information to answer the questions below.
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 tumours. 
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 tumours. 
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.

Question 17

In prophase I of meiosis in female Drosophila,studies have shown that there is phosphorylation of an amino acid in the tails of histones of gametes.A mutation in flies that interferes with this process results in sterility.Which of the following is the most likely hypothesis?

Accepted Answer

A) These oocytes have no histones. 
B) Any mutation during oogenesis results in sterility. 
C) All proteins in the cell must be phosphorylated. 
D) Histone tail phosphorylation prohibits chromosome condensation. 
E) Histone tails must be removed from the rest of the histones. 
A) These oocytes have no histones. 
B) Any mutation during oogenesis results in sterility. 
C) All proteins in the cell must be phosphorylated. 
D) Histone tail phosphorylation prohibits chromosome condensation. 
E) Histone tails must be removed from the rest of the histones.

Question 18

Use the following information to answer the questions below.
Epstein Barr 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 19

For a repressible operon to be transcribed,which of the following must occur?

Accepted Answer

A) A corepressor must be present. 
B) RNA polymerase and the active repressor must be present. 
C) RNA polymerase must bind to the promoter, and the repressor must be inactive. 
D) RNA polymerase cannot be present, and the repressor must be inactive. 
E) RNA polymerase must not occupy the promoter, and the repressor must be inactive. 
A) A corepressor must be present. 
B) RNA polymerase and the active repressor must be present. 
C) RNA polymerase must bind to the promoter, and the repressor must be inactive. 
D) RNA polymerase cannot be present, and the repressor must be inactive. 
E) RNA polymerase must not occupy the promoter, and the repressor must be inactive.

Question 20

Use the following information to answer the questions below.
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.
-Two children are born from the same parents.Child one inherits a predisposition to retinoblastoma (one of the mutations)and child two does not.However,both children develop the retinoblastoma.Which of the following would you expect?

Accepted Answer

A) an earlier age of onset in child one 
B) a history of exposure to mutagens in child one but not in child two 
C) a more severe cancer in child one 
D) increased levels of apoptosis in both children 
E) decreased levels of DNA repair in child one 
A) an earlier age of onset in child one 
B) a history of exposure to mutagens in child one but not in child two 
C) a more severe cancer in child one 
D) increased levels of apoptosis in both children 
E) decreased levels of DNA repair in child one

Exam 18: Regulation of Gene Expression

The term epigenetics refers to

In eukaryotes,general transcription factors

How does extracellular glucose inhibits transcription of the lac operon?

Why is the number of protein-coding genes not equivalent to the number of proteins produced in any given eukaryotic species?

Transcription factors in eukaryotes usually have DNA binding domains as well as other domains that are also specific for binding.In general,which of the following would you expect many of them to be able to bind?

The lactose operon is likely to be transcribed when

Which of the following best describes siRNA?

The functioning of enhancers is an example of

Use the following figure to answer the questions below. -What does D represent?

Which of the following describes the function of an enzyme known as Dicer?

Drosophila larvae (wt)showing segmentation and anterior-posterior axis. Refer to the image above to answer the following questions. -What would happen if the larvae developed a mutation in the bicoid gene?

During DNA replication

Which of the following types of RNA are involved in RNAi?

In prophase I of meiosis in female Drosophila,studies have shown that there is phosphorylation of an amino acid in the tails of histones of gametes.A mutation in flies that interferes with this process results in sterility.Which of the following is the most likely hypothesis?

For a repressible operon to be transcribed,which of the following must occur?

Introduction: Evolution and Themes of Biology

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

DNA Tools and 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 Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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