Question 1

BRCA1 and BRCA2 are considered to be tumour-suppressor genes because

Accepted Answer

A) they prevent infection by retroviruses that cause cancer. 
B) their normal products participate in repair of DNA damage. 
C) the mutant forms of either one of these promote breast cancer. 
D) the normal genes make estrogen receptors. 
E) they block penetration of breast cells by chemical carcinogens. 
A) they prevent infection by retroviruses that cause cancer. 
B) their normal products participate in repair of DNA damage. 
C) the mutant forms of either one of these promote breast cancer. 
D) the normal genes make estrogen receptors. 
E) they block penetration of breast cells by chemical carcinogens.

Question 2

Use the following information to answer the questions below.
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.
-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 3

If you were to observe the activity of methylated DNA, you would expect it to

Accepted Answer

A) be replicating nearly continuously. 
B) be unwinding in preparation for protein synthesis. 
C) have turned off or slowed down the process of transcription. 
D) be very actively transcribed and translated. 
E) induce protein synthesis by not allowing repressors to bind to it. 
A) be replicating nearly continuously. 
B) be unwinding in preparation for protein synthesis. 
C) have turned off or slowed down the process of transcription. 
D) be very actively transcribed and translated. 
E) induce protein synthesis by not allowing repressors to bind to it.

Question 4

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 5

Use the following figure to answer the questions below.
  
-Of the images displayed above, which represents DNA?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 6

Forms of the Ras protein found in tumours usually cause which of the following?

Accepted Answer

A) DNA replication to stop 
B) DNA replication to be hyperactive 
C) cell-to-cell adhesion to be nonfunctional 
D) cell division to cease 
E) growth factor signalling to be hyperactive 
A) DNA replication to stop 
B) DNA replication to be hyperactive 
C) cell-to-cell adhesion to be nonfunctional 
D) cell division to cease 
E) growth factor signalling to be hyperactive

Question 7

Within a cell, the amount of protein made using a given mRNA molecule depends partly on

Accepted Answer

A) the degree of DNA methylation. 
B) the rate at which the mRNA is degraded. 
C) the presence of certain transcription factors. 
D) the number of introns present in the mRNA. 
E) the types of ribosomes present in the cytoplasm. 
A) the degree of DNA methylation. 
B) the rate at which the mRNA is degraded. 
C) the presence of certain transcription factors. 
D) the number of introns present in the mRNA. 
E) the types of ribosomes present in the cytoplasm.

Question 8

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 9

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 10

Mutations in which of the following genes lead to transformations in the identity of entire body parts?

Accepted Answer

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

Question 11

In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. This is due to

Accepted Answer

A) nonidentical genes that produce different versions of globins during development. 
B) identical genes that generate many copies of the ribosomes needed for fetal globin production. 
C) pseudogenes, which interfere with gene expression in adults. 
D) the attachment of methyl groups to cytosine following birth, which changes the type of hemoglobin produced. 
E) histone proteins changing shape during embryonic development. 
A) nonidentical genes that produce different versions of globins during development. 
B) identical genes that generate many copies of the ribosomes needed for fetal globin production. 
C) pseudogenes, which interfere with gene expression in adults. 
D) the attachment of methyl groups to cytosine following birth, which changes the type of hemoglobin produced. 
E) histone proteins changing shape during embryonic development.

Question 12

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 13

The cancer-causing forms of the Ras protein are involved in which of the following processes?

Accepted Answer

A) relaying a signal from a growth factor receptor 
B) DNA replication 
C) DNA repair 
D) cell-cell adhesion 
E) cell division 
A) relaying a signal from a growth factor receptor 
B) DNA replication 
C) DNA repair 
D) cell-cell adhesion 
E) cell division

Question 14

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 15

Use the following information to answer the questions below.
Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome.
-If she moves the operator to a position upstream from the promoter, what would occur?

Accepted Answer

A) The lac operon will function normally. 
B) The lac operon will be expressed continuously. 
C) The repressor will not be able to bind to the operator. 
D) The repressor will bind to the promoter. 
E) The repressor will no longer be made. 
A) The lac operon will function normally. 
B) The lac operon will be expressed continuously. 
C) The repressor will not be able to bind to the operator. 
D) The repressor will bind to the promoter. 
E) The repressor will no longer be made.

Question 16

Genomic imprinting, DNA methylation, and histone acetylation are all examples of

Accepted Answer

A) genetic mutation. 
B) chromosomal rearrangements. 
C) karyotypes. 
D) epigenetic phenomena. 
E) translocation. 
A) genetic mutation. 
B) chromosomal rearrangements. 
C) karyotypes. 
D) epigenetic phenomena. 
E) translocation.

Question 17

Since Watson and Crick described DNA in 1953, which of the following might best explain why the function of small RNAs is still being explained?

Accepted Answer

A) As RNAs have evolved since that time, they have taken on new functions. 
B) Watson and Crick described DNA but did not predict any function for RNA. 
C) The functions of small RNAs could not be approached until the entire human genome was sequenced. 
D) Ethical considerations prevented scientists from exploring this material until recently. 
E) Changes in technology as well as our ability to determine how much of the DNA is expressed have now made this possible. 
A) As RNAs have evolved since that time, they have taken on new functions. 
B) Watson and Crick described DNA but did not predict any function for RNA. 
C) The functions of small RNAs could not be approached until the entire human genome was sequenced. 
D) Ethical considerations prevented scientists from exploring this material until recently. 
E) Changes in technology as well as our ability to determine how much of the DNA is expressed have now made this possible.

Question 18

Among the newly discovered small noncoding RNAs, one type re-establishes methylation patterns during gamete formation and blocks expression of some transposons. This type is known as

Accepted Answer

A) miRNA. 
B) piRNA. 
C) snRNA. 
D) siRNA. 
E) RNAi. 
A) miRNA. 
B) piRNA. 
C) snRNA. 
D) siRNA. 
E) RNAi.

Question 19

In a series of experiments, the enzyme Dicer has been inactivated in cells from various vertebrates so that the centromere is abnormally formed from chromatin. Which of the following is most likely to occur?

Accepted Answer

A) The usual mRNAs transcribed from centromeric DNA will be missing from the cells. 
B) Tetrads will no longer be able to form during meiosis I. 
C) Centromeres will be euchromatic rather than heterochromatic and the cells will soon die in culture. 
D) The cells will no longer be able to resist bacterial contamination. 
E) The DNA of the centromeres will no longer be able to replicate. 
A) The usual mRNAs transcribed from centromeric DNA will be missing from the cells. 
B) Tetrads will no longer be able to form during meiosis I. 
C) Centromeres will be euchromatic rather than heterochromatic and the cells will soon die in culture. 
D) The cells will no longer be able to resist bacterial contamination. 
E) The DNA of the centromeres will no longer be able to replicate.

Question 20

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

Exam 18: Regulation of Gene Expression

BRCA1 and BRCA2 are considered to be tumour-suppressor genes because

If you were to observe the activity of methylated DNA, you would expect it to

Muscle cells differ from nerve cells mainly because they

Use the following figure to answer the questions below. -Of the images displayed above, which represents DNA?

Forms of the Ras protein found in tumours usually cause which of the following?

Within a cell, the amount of protein made using a given mRNA molecule depends partly on

During DNA replication

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?

Mutations in which of the following genes lead to transformations in the identity of entire body parts?

In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. This is due to

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?

The cancer-causing forms of the Ras protein are involved in which of the following processes?

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

Use the following information to answer the questions below. Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. -If she moves the operator to a position upstream from the promoter, what would occur?

Genomic imprinting, DNA methylation, and histone acetylation are all examples of

Since Watson and Crick described DNA in 1953, which of the following might best explain why the function of small RNAs is still being explained?

Among the newly discovered small noncoding RNAs, one type re-establishes methylation patterns during gamete formation and blocks expression of some transposons. This type is known as

In a series of experiments, the enzyme Dicer has been inactivated in cells from various vertebrates so that the centromere is abnormally formed from chromatin. Which of the following is most likely to occur?

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

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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