Question 1

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 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

Question 3

A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in

Accepted Answer

A) continuous transcription of the gene controlled by that regulator. 
B) complete inhibition of transcription of the gene controlled by that regulator. 
C) irreversible binding of the repressor to the operator. 
D) inactivation of RNA polymerase by alteration of its active site. 
E) continuous translation of the mRNA because of alteration of its structure. 
A) continuous transcription of the gene controlled by that regulator. 
B) complete inhibition of transcription of the gene controlled by that regulator. 
C) irreversible binding of the repressor to the operator. 
D) inactivation of RNA polymerase by alteration of its active site. 
E) continuous translation of the mRNA because of alteration of its structure.

Question 4

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

Question 5

Use the following figure to answer the questions below.
  
-What has happened to make the products C and D?

Accepted Answer

A) frame shift mutation 
B) loss of introns 
C) mRNA degradation 
D) incorrect 5' cap placement 
E) alternative splicing 
A) frame shift mutation 
B) loss of introns 
C) mRNA degradation 
D) incorrect 5' cap placement 
E) alternative splicing

Question 6

At the beginning of this century there was a general announcement regarding the sequencing of the human genome and the genomes of many other multicellular eukaryotes. There was surprise expressed by many that the number of protein-coding sequences was much smaller than they had expected. Which of the following could account for most of the rest?

Accepted Answer

A) "junk" DNA that serves no possible purpose 
B) rRNA and tRNA coding sequences 
C) DNA that is translated directly without being transcribed 
D) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function 
E) non-protein-coding DNA that is transcribed into several kinds of small RNAs without biological function 
A) "junk" DNA that serves no possible purpose 
B) rRNA and tRNA coding sequences 
C) DNA that is translated directly without being transcribed 
D) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function 
E) non-protein-coding DNA that is transcribed into several kinds of small RNAs without biological function

Question 7

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 8

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 9

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.
-The researcher continues to study the reactions of the embryo to these new proteins and you hypothesize that he is most likely to see which of the following (while embryonic genes are still not being expressed)?

Accepted Answer

A) The cells begin to differentiate. 
B) The proteins are evenly distributed throughout the embryo. 
C) Larval features begin to make their appearance. 
D) Spatial axes (anterior → posterior, etc.)begin to be determined. 
E) The embryo begins to lose cells due to apoptosis from no further gene expression. 
A) The cells begin to differentiate. 
B) The proteins are evenly distributed throughout the embryo. 
C) Larval features begin to make their appearance. 
D) Spatial axes (anterior → posterior, etc.)begin to be determined. 
E) The embryo begins to lose cells due to apoptosis from no further gene expression.

Question 10

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 11

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 12

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.
-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 13

Which of the following experimental procedures is most likely to hasten mRNA degradation in a eukaryotic cell?

Accepted Answer

A) enzymatic shortening of the poly-A tail 
B) removal of the 5' cap 
C) methylation of C nucleotides 
D) methylation of histones 
E) removal of one or more exons 
A) enzymatic shortening of the poly-A tail 
B) removal of the 5' cap 
C) methylation of C nucleotides 
D) methylation of histones 
E) removal of one or more exons

Question 14

A genetic test to detect predisposition to cancer would likely examine the APC gene for involvement in which type(s)of cancer?

Accepted Answer

A) colorectal only 
B) lung and breast 
C) small intestinal and esophageal 
D) lung only 
E) lung and prostate 
A) colorectal only 
B) lung and breast 
C) small intestinal and esophageal 
D) lung only 
E) lung and prostate

Question 15

Drosophila larvae (wt) showing segmentation and anterior-posterior axis.
Refer to the image above to answer the following questions.
-The orientation of this larva is a result of

Accepted Answer

A) cytological determinants. 
B) larval gene expression. 
C) proximity to other larvae. 
D) homeotic genes. 
E) p53 gene. 
A) cytological determinants. 
B) larval gene expression. 
C) proximity to other larvae. 
D) homeotic genes. 
E) p53 gene.

Question 16

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 17

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 18

Use the following information to answer the questions below.
A researcher introduces double-stranded RNA into a culture of mammalian cells, and can identify its location or that of its smaller subsections experimentally, using a fluorescent probe.
-Some time later, she finds that the introduced strand separates into single-stranded RNAs, one of which is degraded. What does this enable the remaining strand to do?

Accepted Answer

A) attach to histones in the chromatin 
B) bind to complementary regions of target mRNAs 
C) bind to Dicer enzymes to destroy other RNAs 
D) activate other siRNAs in the cell 
E) bind to noncomplementary RNA sequences 
A) attach to histones in the chromatin 
B) bind to complementary regions of target mRNAs 
C) bind to Dicer enzymes to destroy other RNAs 
D) activate other siRNAs in the cell 
E) bind to noncomplementary RNA sequences

Question 19

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

Question 20

Which of the following is characteristic of the product of the p53 gene?

Accepted Answer

A) It is an activator for other genes. 
B) It speeds up the cell cycle. 
C) It causes cell death via apoptosis. 
D) It allows cells to pass on mutations due to DNA damage. 
E) It slows down the rate of DNA replication by interfering with the binding of DNA polymerase. 
A) It is an activator for other genes. 
B) It speeds up the cell cycle. 
C) It causes cell death via apoptosis. 
D) It allows cells to pass on mutations due to DNA damage. 
E) It slows down the rate of DNA replication by interfering with the binding of DNA polymerase.

Exam 18: Regulation of Gene Expression

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 is a protein produced by a regulatory gene?

A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in

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?

Use the following figure to answer the questions below. -What has happened to make the products C and D?

The tryptophan operon is a repressible operon that is

The lactose operon is likely to be transcribed when

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

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?

Which of the following experimental procedures is most likely to hasten mRNA degradation in a eukaryotic cell?

A genetic test to detect predisposition to cancer would likely examine the APC gene for involvement in which type(s)of cancer?

Drosophila larvae (wt) showing segmentation and anterior-posterior axis. Refer to the image above to answer the following questions. -The orientation of this larva is a result of

Which of the following best describes siRNA?

Which of the following is characteristic of the product of the p53 gene?

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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