Question 1

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 E

Question 2

Which of the following is a protein produced by a regulatory gene?

Accepted Answer

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

Question 3

When does the trp repressor block transcription of the trp operon?

Accepted Answer

A) when TrpR binds to the inducer 
B) when TrpR binds to tryptophan 
C) when TrpR is not bound to tryptophan 
D) when TrpR is not bound to the operator 
E) when TrpR binds to the promoter 
A) when TrpR binds to the inducer 
B) when TrpR binds to tryptophan 
C) when TrpR is not bound to tryptophan 
D) when TrpR is not bound to the operator 
E) when TrpR binds to the promoter B

Question 4

What is the primary difference between enhancers and promoter-proximal elements?

Accepted Answer

A) Enhancers are transcription factors, while promoter-proximal elements are DNA sequences. 
B) Enhancers enhance transcription, while promoter-proximal elements inhibit transcription. 
C) Enhancers act at considerable distances from the promoter, while promoter-proximal elements are close to the promoter. 
D) Enhancers are DNA sequences, while promoter-proximal elements are proteins. 
E) Enhancers increase translation, while promoter-proximal elements enhance transcription. 
A) Enhancers are transcription factors, while promoter-proximal elements are DNA sequences. 
B) Enhancers enhance transcription, while promoter-proximal elements inhibit transcription. 
C) Enhancers act at considerable distances from the promoter, while promoter-proximal elements are close to the promoter. 
D) Enhancers are DNA sequences, while promoter-proximal elements are proteins. 
E) Enhancers increase translation, while promoter-proximal elements enhance transcription.

Question 5

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

Accepted Answer

A) irreversible binding of the repressor to the promoter 
B) reduced transcription of the operon's genes 
C) buildup of a substrate for the pathway controlled by the operon 
D) continuous transcription of the operon's genes 
E) overproduction of catabolite activator protein (CAP) 
A) irreversible binding of the repressor to the promoter 
B) reduced transcription of the operon's genes 
C) buildup of a substrate for the pathway controlled by the operon 
D) continuous transcription of the operon's genes 
E) overproduction of catabolite activator protein (CAP)

Question 6

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.
-Which of the following types of mutation would convert a proto-oncogene into an oncogene?

Accepted Answer

A) a mutation that blocks transcription of the proto-oncogene 
B) a mutation that creates an unstable proto-oncogene mRNA 
C) a mutation that greatly increases the amount of the proto-oncogene protein 
D) a deletion of most of the proto-oncogene coding sequence 
E) a deletion of the 5' upstream region of the proto-oncogene coding sequence 
A) a mutation that blocks transcription of the proto-oncogene 
B) a mutation that creates an unstable proto-oncogene mRNA 
C) a mutation that greatly increases the amount of the proto-oncogene protein 
D) a deletion of most of the proto-oncogene coding sequence 
E) a deletion of the 5' upstream region of the proto-oncogene coding sequence

Question 7

Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways?

Accepted Answer

A) organizing gene expression so that genes are expressed in a given order 
B) allowing each gene to be expressed an equal number of times 
C) allowing the organism to adjust to changes in environmental conditions 
D) allowing young organisms to respond differently from more mature organisms 
E) allowing environmental changes to alter the prokaryote's genome 
A) organizing gene expression so that genes are expressed in a given order 
B) allowing each gene to be expressed an equal number of times 
C) allowing the organism to adjust to changes in environmental conditions 
D) allowing young organisms to respond differently from more mature organisms 
E) allowing environmental changes to alter the prokaryote's genome

Question 8

Drosophila larvae (wt)showing segmentation and anterior-posterior axis.
Refer to the image above to answer the following questions.
-When is a cell considered to be differentiated?

Accepted Answer

A) When it replicates by the process of mitosis. 
B) When it loses connections to the surrounding cells. 
C) When it produces proteins specific to a particular cell type. 
D) When it appears to be different from the surrounding cells. 
E) When it has transcribed all of its genes. 
A) When it replicates by the process of mitosis. 
B) When it loses connections to the surrounding cells. 
C) When it produces proteins specific to a particular cell type. 
D) When it appears to be different from the surrounding cells. 
E) When it has transcribed all of its genes.

Question 9

Which processes contribute to this dynamic compacting and decompacting of DNA?

Accepted Answer

A) DNA supercoiling at or around H1 
B) methylation and phosphorylation of histone tails 
C) hydrolysis of DNA molecules where they are wrapped around the nucleosome core 
D) accessibility of heterochromatin to phosphorylating enzymes 
E) nucleotide excision and reconstruction 
A) DNA supercoiling at or around H1 
B) methylation and phosphorylation of histone tails 
C) hydrolysis of DNA molecules where they are wrapped around the nucleosome core 
D) accessibility of heterochromatin to phosphorylating enzymes 
E) nucleotide excision and reconstruction

Question 10

Why is CAP said to be responsible for positive regulation of the lac operon?

Accepted Answer

A) Because CAP binds cAMP 
B) Because CAP binds to the CAP-binding site 
C) Because CAP prevents binding of the repressor to the operator 
D) Because CAP bound to the CAP-binding site increases the frequency of transcription initiation 
E) Because CAP binds to the lac operator when glucose is scarce 
A) Because CAP binds cAMP 
B) Because CAP binds to the CAP-binding site 
C) Because CAP prevents binding of the repressor to the operator 
D) Because CAP bound to the CAP-binding site increases the frequency of transcription initiation 
E) Because CAP binds to the lac operator when glucose is scarce

Question 11

Use the following information to answer the questions below.
A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture.
-In one set of experiments using this procedure in Drosophila,she was readily successful in increasing phosphorylation of amino acids adjacent to methylated amino acids in histone tails.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 12

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 13

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 14

Tumour-suppressor genes

Accepted Answer

A) are frequently overexpressed in cancerous cells. 
B) are cancer-causing genes introduced into cells by viruses. 
C) can encode proteins that promote DNA repair or cell-cell adhesion. 
D) often encode proteins that stimulate the cell cycle. 
E) do all of the above. 
A) are frequently overexpressed in cancerous cells. 
B) are cancer-causing genes introduced into cells by viruses. 
C) can encode proteins that promote DNA repair or cell-cell adhesion. 
D) often encode proteins that stimulate the cell cycle. 
E) do all of the above.

Question 15

Which of the following statements describes proto-oncogenes?

Accepted Answer

A) Their normal function is to suppress tumour growth. 
B) They are introduced to a cell initially by retroviruses. 
C) They are produced by somatic mutations induced by carcinogenic substances. 
D) They can code for proteins associated with cell growth. 
E) They are underexpressed in cancer cells. 
A) Their normal function is to suppress tumour growth. 
B) They are introduced to a cell initially by retroviruses. 
C) They are produced by somatic mutations induced by carcinogenic substances. 
D) They can code for proteins associated with cell growth. 
E) They are underexpressed in cancer cells.

Question 16

The transformation from a zygote to a full-formed organism involves three interrelated processes.In order of occurrence,they are

Accepted Answer

A) morphogenesis, cell division, cell differentiation. 
B) fertilization, cell division, tissue formation. 
C) fertilization, cell division, cell differentiation. 
D) cell division, cell differentiation, morphogenesis. 
E) polarity, cell differentiation, segmentation. 
A) morphogenesis, cell division, cell differentiation. 
B) fertilization, cell division, tissue formation. 
C) fertilization, cell division, cell differentiation. 
D) cell division, cell differentiation, morphogenesis. 
E) polarity, cell differentiation, segmentation.

Question 17

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 18

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 the far end of the operon (past the transacetylase gene),which of the following would likely occur when the cell is exposed to lactose?

Accepted Answer

A) The inducer will no longer bind to the repressor. 
B) The repressor will no longer bind to the operator. 
C) The operon will never be transcribed. 
D) The genes will be transcribed continuously. 
E) The repressor protein will no longer be produced. 
A) The inducer will no longer bind to the repressor. 
B) The repressor will no longer bind to the operator. 
C) The operon will never be transcribed. 
D) The genes will be transcribed continuously. 
E) The repressor protein will no longer be produced.

Question 19

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 20

Your brother has just purchased a new plastic model airplane.He places all the parts on the table in approximately the positions in which they will be located when the model is complete.His actions are analogous to which process in development?

Accepted Answer

A) morphogenesis 
B) determination 
C) induction 
D) differentiation 
E) pattern formation 
A) morphogenesis 
B) determination 
C) induction 
D) differentiation 
E) pattern formation

Exam 18: Regulation of Gene Expression

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

Which of the following is a protein produced by a regulatory gene?

When does the trp repressor block transcription of the trp operon?

What is the primary difference between enhancers and promoter-proximal elements?

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways?

Drosophila larvae (wt)showing segmentation and anterior-posterior axis. Refer to the image above to answer the following questions. -When is a cell considered to be differentiated?

Which processes contribute to this dynamic compacting and decompacting of DNA?

Why is CAP said to be responsible for positive regulation of the lac operon?

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

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

Tumour-suppressor genes

Which of the following statements describes proto-oncogenes?

The transformation from a zygote to a full-formed organism involves three interrelated processes.In order of occurrence,they are

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

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?

Your brother has just purchased a new plastic model airplane.He places all the parts on the table in approximately the positions in which they will be located when the model is complete.His actions are analogous to which process in development?

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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