Question 1

Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation?

Accepted Answer

A) inducer 
B) promoter 
C) RNA polymerase 
D) transcription factor 
E) cAMP 
A) inducer 
B) promoter 
C) RNA polymerase 
D) transcription factor 
E) cAMP

Question 2

Which of the following statements about the DNA in one of your brain cells is true?

Accepted Answer

A) Most of the DNA codes for protein. 
B) The majority of genes are likely to be transcribed. 
C) Each gene lies immediately adjacent to an enhancer. 
D) Many genes are grouped into operon-like clusters. 
E) It is the same as the DNA in one of your heart cells. 
A) Most of the DNA codes for protein. 
B) The majority of genes are likely to be transcribed. 
C) Each gene lies immediately adjacent to an enhancer. 
D) Many genes are grouped into operon-like clusters. 
E) It is the same as the DNA in one of your heart cells.

Question 3

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.
-A very rare human allele of a gene called XLP, or X-linked lymphoproliferative syndrome, causes a small number of people from many different parts of the world to get cancer following even childhood exposure to EBV. Given the previous information, what might be going on?

Accepted Answer

A) The people must have previously had malaria. 
B) Their ancestors must be from sub-Saharan Africa or southeast Asia. 
C) They must be unable to mount an immune response to EBV. 
D) They must have severe combined immune deficiency (SCI
D) . 
E) Their whole immune system must be overreplicating. 
A) The people must have previously had malaria. 
B) Their ancestors must be from sub-Saharan Africa or southeast Asia. 
C) They must be unable to mount an immune response to EBV. 
D) They must have severe combined immune deficiency (SCI
D) . 
E) Their whole immune system must be overreplicating.

Question 4

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 5

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 6

Use the following information to answer the questions below.
A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all.
-Of the lines that express the transgene, one is transcribed but not translated. Which of the following is a likely explanation?

Accepted Answer

A) no promoter 
B) no AUG in any frame 
C) no compatible ribosome 
D) high histone acetylation 
E) missing transcription factor 
A) no promoter 
B) no AUG in any frame 
C) no compatible ribosome 
D) high histone acetylation 
E) missing transcription factor

Question 7

Which of the following mechanisms is (are)used to coordinate the expression of multiple, related genes in eukaryotic cells?

Accepted Answer

A) Genes are organized into clusters, with local chromatin structures influencing the expression of all the genes at once. 
B) The genes share a common intragenic sequence, and allow several activators to turn on their transcription, regardless of location. 
C) The genes are organized into large operons, allowing them to be transcribed as a single unit. 
D) A single repressor is able to turn off several related genes. 
E) Environmental signals enter the cell and bind directly to promoters. 
A) Genes are organized into clusters, with local chromatin structures influencing the expression of all the genes at once. 
B) The genes share a common intragenic sequence, and allow several activators to turn on their transcription, regardless of location. 
C) The genes are organized into large operons, allowing them to be transcribed as a single unit. 
D) A single repressor is able to turn off several related genes. 
E) Environmental signals enter the cell and bind directly to promoters.

Question 8

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.
-If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then

Accepted Answer

A) the amino acid inactivates the repressor. 
B) the enzymes produced are called inducible enzymes. 
C) the repressor is active in the absence of the amino acid. 
D) the amino acid acts as a corepressor. 
E) the amino acid turns on transcription of the operon. 
A) the amino acid inactivates the repressor. 
B) the enzymes produced are called inducible enzymes. 
C) the repressor is active in the absence of the amino acid. 
D) the amino acid acts as a corepressor. 
E) the amino acid turns on transcription of the operon.

Question 9

Steroid hormones produce their effects in cells by

Accepted Answer

A) activating key enzymes in metabolic pathways. 
B) activating translation of certain mRNAs. 
C) promoting the degradation of specific mRNAs. 
D) binding to intracellular receptors and promoting transcription of specific genes. 
E) promoting the formation of looped domains in certain regions of DNA. 
A) activating key enzymes in metabolic pathways. 
B) activating translation of certain mRNAs. 
C) promoting the degradation of specific mRNAs. 
D) binding to intracellular receptors and promoting transcription of specific genes. 
E) promoting the formation of looped domains in certain regions of DNA.

Question 10

Use the following information to answer the questions below.
A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all.
-Which of the following is a likely explanation for the lack of transgene expression in the fifth cell line?

Accepted Answer

A) A transgene integrated into a heterochromatic region of the genome. 
B) A transgene integrated into a euchromatic region of the genome. 
C) The transgene was mutated during the process of integration into the host cell genome. 
D) The host cell lacks the enzymes necessary to express the transgene. 
E) A transgene integrated into a region of the genome characterized by high histone acetylation. 
A) A transgene integrated into a heterochromatic region of the genome. 
B) A transgene integrated into a euchromatic region of the genome. 
C) The transgene was mutated during the process of integration into the host cell genome. 
D) The host cell lacks the enzymes necessary to express the transgene. 
E) A transgene integrated into a region of the genome characterized by high histone acetylation.

Question 11

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.
-One of the human leukemias, called CML (chronic myelogenous leukemia), is associated with a chromosomal translocation between chromosomes 9 and 22 in somatic cells of bone marrow. Which of the following allows CML to provide further evidence of this multistep nature of cancer?

Accepted Answer

A) CML usually occurs in more elderly persons (late age of onset). 
B) The resulting chromosome 22 is abnormally short; it is then known as the Philadelphia chromosome. 
C) The translocation requires breaks in both chromosomes 9 and 22, followed by fusion between the reciprocal pieces. 
D) CML involves a proto-oncogene known as abl. 
E) CML can usually be treated by chemotherapy. 
A) CML usually occurs in more elderly persons (late age of onset). 
B) The resulting chromosome 22 is abnormally short; it is then known as the Philadelphia chromosome. 
C) The translocation requires breaks in both chromosomes 9 and 22, followed by fusion between the reciprocal pieces. 
D) CML involves a proto-oncogene known as abl. 
E) CML can usually be treated by chemotherapy.

Question 12

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.
-In colorectal cancer, several genes must be mutated in order to make a cell a cancer cell, supporting Knudsen's hypothesis. Which of the following kinds of genes would you expect to be mutated?

Accepted Answer

A) genes coding for enzymes that act in the colon 
B) genes involved in control of the cell cycle 
C) genes that are especially susceptible to mutation 
D) the same genes that Knudsen identified as associated with retinoblastoma 
E) the genes of the bacteria that are abundant in the colon 
A) genes coding for enzymes that act in the colon 
B) genes involved in control of the cell cycle 
C) genes that are especially susceptible to mutation 
D) the same genes that Knudsen identified as associated with retinoblastoma 
E) the genes of the bacteria that are abundant in the colon

Question 13

Drosophila larvae (wt) showing segmentation and anterior-posterior axis.
Refer to the image above to answer the following questions.
-Which gene is definitely functioning in the mother of this larva?

Accepted Answer

A) ras 
B) p53 
C) bicoid 
D) myoD 
E) You cannot tell from this larva. 
A) ras 
B) p53 
C) bicoid 
D) myoD 
E) You cannot tell from this larva.

Question 14

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.
-Within the first quarter hour, the researcher sees that the intact RNA is found in the cells. After 3 hours, she is not surprised to find that

Accepted Answer

A) Dicer enzyme has reduced it to smaller double-stranded pieces. 
B) the RNA is degraded by 5' and 3' exonucleases. 
C) the double-stranded RNA replicates itself. 
D) the double-stranded RNA binds to mRNAs to prevent translation. 
E) the double-stranded RNA binds to tRNAs to prevent translation. 
A) Dicer enzyme has reduced it to smaller double-stranded pieces. 
B) the RNA is degraded by 5' and 3' exonucleases. 
C) the double-stranded RNA replicates itself. 
D) the double-stranded RNA binds to mRNAs to prevent translation. 
E) the double-stranded RNA binds to tRNAs to prevent translation.

Question 15

Use the following figure to answer the questions below.
  
-What is the significance of the configuration between A and B?

Accepted Answer

A) A's configuration will not allow transcription. 
B) B's configuration allows for better packing of the chromatin. 
C) B's configuration provides a means for translation to occur. 
D) B is a polysome and will be able to make more protein faster. 
E) A is a centromere and so remains condensed. 
A) A's configuration will not allow transcription. 
B) B's configuration allows for better packing of the chromatin. 
C) B's configuration provides a means for translation to occur. 
D) B is a polysome and will be able to make more protein faster. 
E) A is a centromere and so remains condensed.

Question 16

When DNA is compacted by histones into 10-nm and 30-nm fibres, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity?

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 17

Two potential devices that eukaryotic cells use to regulate transcription are

Accepted Answer

A) DNA methylation and histone amplification. 
B) DNA amplification and histone methylation. 
C) DNA acetylation and methylation. 
D) DNA methylation and histone modification. 
E) histone amplification and DNA acetylation. 
A) DNA methylation and histone amplification. 
B) DNA amplification and histone methylation. 
C) DNA acetylation and methylation. 
D) DNA methylation and histone modification. 
E) histone amplification and DNA acetylation.

Question 18

The product of the bicoid gene in Drosophila provides essential information about

Accepted Answer

A) lethal genes. 
B) the dorsal-ventral axis. 
C) the left-right axis. 
D) segmentation. 
E) the anterior-posterior axis. 
A) lethal genes. 
B) the dorsal-ventral axis. 
C) the left-right axis. 
D) segmentation. 
E) the anterior-posterior axis.

Question 19

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 she succeeded in decreasing methylation of 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 20

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.

Exam 18: Regulation of Gene Expression

Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation?

Which of the following statements about the DNA in one of your brain cells is true?

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?

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

Which of the following mechanisms is (are)used to coordinate the expression of multiple, related genes in eukaryotic cells?

Steroid hormones produce their effects in cells by

Drosophila larvae (wt) showing segmentation and anterior-posterior axis. Refer to the image above to answer the following questions. -Which gene is definitely functioning in the mother of this larva?

Use the following figure to answer the questions below. -What is the significance of the configuration between A and B?

When DNA is compacted by histones into 10-nm and 30-nm fibres, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity?

Two potential devices that eukaryotic cells use to regulate transcription are

The product of the bicoid gene in Drosophila provides essential information about

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