Question 1

Cell differentiation always involves the

Accepted Answer

A) production of tissue-specific proteins, such as muscle actin. 
B) movement of cells. 
C) transcription of the myoD gene. 
D) selective loss of certain genes from the genome. 
E) cell's sensitivity to environmental cues such as light or heat. 
A) production of tissue-specific proteins, such as muscle actin. 
B) movement of cells. 
C) transcription of the myoD gene. 
D) selective loss of certain genes from the genome. 
E) cell's sensitivity to environmental cues such as light or heat. A

Question 2

A cell that remains entirely flexible in its developmental possibilities is said to be

Accepted Answer

A) differentiated. 
B) determined. 
C) totipotent. 
D) genomically equivalent. 
E) epigenetic. 
A) differentiated. 
B) determined. 
C) totipotent. 
D) genomically equivalent. 
E) epigenetic. C

Question 3

The incidence of cancer increases dramatically in older humans because

Accepted Answer

A) the Ras protein is more likely to be hyperactive after age sixty. 
B) proteasomes become more active with age. 
C) as we age, normal cell division inhibitors cease to function. 
D) the longer we live, the more mutations we accumulate. 
E) tumor-suppressor genes are no longer able to repair damaged DNA. 
A) the Ras protein is more likely to be hyperactive after age sixty. 
B) proteasomes become more active with age. 
C) as we age, normal cell division inhibitors cease to function. 
D) the longer we live, the more mutations we accumulate. 
E) tumor-suppressor genes are no longer able to repair damaged DNA. D

Question 4

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. Which of the following best describes this phenomenon?

Accepted Answer

A) inherited cancer taking a few years to be expressed 
B) embryonic or fetal cancer 
C) inherited predisposition to mutation 
D) inherited inability to repair UV-induced mutation 
E) susceptibility to chemical carcinogens 
A) inherited cancer taking a few years to be expressed 
B) embryonic or fetal cancer 
C) inherited predisposition to mutation 
D) inherited inability to repair UV-induced mutation 
E) susceptibility to chemical carcinogens

Question 5

Use the following scenario for the following questions.
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.
-If there are two children born from the same parents, and child one inherits a predisposition to retinoblastoma (one of the mutations)and child two does not, but 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 6

Gap genes and pair-rule genes fall into this category:

Accepted Answer

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

Question 7

Eukaryotic cells can control gene expression by which of the following mechanisms?

Accepted Answer

A) histone acetylation of nucleosomes 
B) DNA acetylation 
C) RNA induced modification of chromatin structure 
D) repression of operons 
E) induction of operators in the promoter 
A) histone acetylation of nucleosomes 
B) DNA acetylation 
C) RNA induced modification of chromatin structure 
D) repression of operons 
E) induction of operators in the promoter

Question 8

The functioning of enhancers is an example of

Accepted Answer

A) transcriptional control of gene expression. 
B) a post-transcriptional mechanism for editing 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 for editing 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

These genes are expressed by the mother, and their products are deposited into the developing egg:

Accepted Answer

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

Question 10

The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur?

Accepted Answer

A) The embryo would grow to an unusually large size. 
B) The embryo would grow extra wings and legs. 
C) The embryo would probably show no anterior development and die. 
D) Anterior structures would form in both sides of the embryo. 
E) The embryo would develop normally. 
A) The embryo would grow to an unusually large size. 
B) The embryo would grow extra wings and legs. 
C) The embryo would probably show no anterior development and die. 
D) Anterior structures would form in both sides of the embryo. 
E) The embryo would develop normally.

Question 11

These genes form gradients and help establish the axes and other features of an embryo:

Accepted Answer

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

Question 12

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 13

The researcher measures the concentration of the polypeptides from different regions in the early embryo and finds the following pattern (darker shading = greater concentration):  
Which of the following would be his most logical assumption?

Accepted Answer

A) The substance has moved quickly from region 5 to region 1. 
B) Some other material in the embryo is causing accumulation in region 1 due to differential binding. 
C) The cytosol is in constant movement, dispersing the polypeptide. 
D) The substance is produced in region 1 and diffuses toward region 5. 
E) The substance must have entered the embryo from the environment near region 1. 
A) The substance has moved quickly from region 5 to region 1. 
B) Some other material in the embryo is causing accumulation in region 1 due to differential binding. 
C) The cytosol is in constant movement, dispersing the polypeptide. 
D) The substance is produced in region 1 and diffuses toward region 5. 
E) The substance must have entered the embryo from the environment near region 1.

Question 14

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 15

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 is much smaller than they had expected. Which of the following accounts 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 16

Which of the following statements describes proto-oncogenes?

Accepted Answer

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

Question 17

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 18

The process of cellular differentiation is a direct result of

Accepted Answer

A) differential gene expression. 
B) morphogenesis. 
C) cell division. 
D) apoptosis. 
E) differences in cellular genomes. 
A) differential gene expression. 
B) morphogenesis. 
C) cell division. 
D) apoptosis. 
E) differences in cellular genomes.

Question 19

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 20

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.

Exam 18: Control of Gene Expression

Cell differentiation always involves the

A cell that remains entirely flexible in its developmental possibilities is said to be

The incidence of cancer increases dramatically in older humans because

Gap genes and pair-rule genes fall into this category:

Eukaryotic cells can control gene expression by which of the following mechanisms?

The functioning of enhancers is an example of

These genes are expressed by the mother, and their products are deposited into the developing egg:

The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur?

These genes form gradients and help establish the axes and other features of an embryo:

Muscle cells differ from nerve cells mainly because they

The researcher measures the concentration of the polypeptides from different regions in the early embryo and finds the following pattern (darker shading = greater concentration): Which of the following would be his most logical assumption?

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

Which of the following statements describes proto-oncogenes?

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?

The process of cellular differentiation is a direct result of

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

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

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and the Fitness of the Environment

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: Harvesting Chemical Energy

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 Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure, Growth, and Development

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

Conservation Biology and Restoration Ecology

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