Question 1

What would be the result of a mutation that deactivates the regulatory gene of a repressible operon in an Escherichia coli cell?

Accepted Answer

A)  continuous transcription of the structural gene controlled by that regulator 
B)  complete inhibition of transcription of the structural 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 structural gene controlled by that regulator 
B)  complete inhibition of transcription of the structural 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 2

Which of the following molecules, when taken up by the cell, binds to the repressor so that the repressor no longer binds to the operator?

Accepted Answer

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

Question 3

Please use the following information to answer the question(s) below.
Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome.
-If she moves the regulatory gene (lac I), along with its promoter, to a position some several thousand base pairs away from its normal position, which would you expect to occur?

Accepted Answer

A)  The repressor will no longer be made. 
B)  The repressor will no longer bind to the operator. 
C)  The repressor will no longer bind to the inducer. 
D)  The lac operon will be expressed continuously. 
E)  The lac operon will function normally. 
A)  The repressor will no longer be made. 
B)  The repressor will no longer bind to the operator. 
C)  The repressor will no longer bind to the inducer. 
D)  The lac operon will be expressed continuously. 
E)  The lac operon will function normally.

Question 4

Figure 15.1
In the microarray shown in Figure 15.1, if you were searching for genes whose expression was inhibited by hormone treatment, you would search for sequences spotted on the array that showed ________ fluorescence.

Accepted Answer

A)  no 
B)  high levels of 
C)  green 
D)  red 
E)  yellow 
A)  no 
B)  high levels of 
C)  green 
D)  red 
E)  yellow

Question 5

A type of mutation in the repressor results in a molecule known as a super-repressor because it represses the lac operon permanently. Which of these would characterize such a mutant?

Accepted Answer

A)  It cannot bind to the operator. 
B)  It cannot make a functional repressor. 
C)  It cannot bind to the inducer. 
D)  It makes molecules that bind to one another. 
A)  It cannot bind to the operator. 
B)  It cannot make a functional repressor. 
C)  It cannot bind to the inducer. 
D)  It makes molecules that bind to one another.

Question 6

Which of the following is a function of the protein called ubiquitin?

Accepted Answer

A)  It attaches to proteins that are marked for destruction in the cell. 
B)  It assists in the removal of introns from a eukaryotic pre-mRNA. 
C)  It initiates the formation of a transcription complex. 
D)  It adds the 3' and 5' caps to eukaryotic pre-mRNA. 
A)  It attaches to proteins that are marked for destruction in the cell. 
B)  It assists in the removal of introns from a eukaryotic pre-mRNA. 
C)  It initiates the formation of a transcription complex. 
D)  It adds the 3' and 5' caps to eukaryotic pre-mRNA.

Question 7

Which statement about 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)  It is the same as the DNA in one of your liver cells. 
D)  Many genes are grouped into operon-like clusters. 
A)  Most of the DNA codes for protein. 
B)  The majority of genes are likely to be transcribed. 
C)  It is the same as the DNA in one of your liver cells. 
D)  Many genes are grouped into operon-like clusters.

Question 8

Transcription factors in eukaryotes usually have DNA-binding domains as well as other domains that are specific for binding other molecules. In general, which of the following would you expect many of them to be able to bind?

Accepted Answer

A)  repressors 
B)  protein-based hormones 
C)  other transcription factors 
D)  tRNA 
A)  repressors 
B)  protein-based hormones 
C)  other transcription factors 
D)  tRNA

Question 9

You are given an experimental problem involving control of a gene's expression in the embryo of a particular species. One of your first questions is whether the gene's expression is controlled at the level of transcription or translation. Which of the following experiments might best give you an answer?

Accepted Answer

A)  You explore whether there has been alternative splicing by examining amino acid sequences of very similar proteins. 
B)  You measure the quantity of the appropriate pre-mRNA in various cell types and find they are all the same. 
C)  You assess the position and sequence of the promoter and enhancer for this gene. 
D)  You analyze amino acid production by the cell and find that there is an increase at this stage of embryonic life. 
A)  You explore whether there has been alternative splicing by examining amino acid sequences of very similar proteins. 
B)  You measure the quantity of the appropriate pre-mRNA in various cell types and find they are all the same. 
C)  You assess the position and sequence of the promoter and enhancer for this gene. 
D)  You analyze amino acid production by the cell and find that there is an increase at this stage of embryonic life.

Question 10

Two potential functions that eukaryotic cells perform 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.

Exam 15: Regulation of Gene Expression

What would be the result of a mutation that deactivates the regulatory gene of a repressible operon in an Escherichia coli cell?

Which of the following molecules, when taken up by the cell, binds to the repressor so that the repressor no longer binds to the operator?

Figure 15.1 In the microarray shown in Figure 15.1, if you were searching for genes whose expression was inhibited by hormone treatment, you would search for sequences spotted on the array that showed ________ fluorescence.

A type of mutation in the repressor results in a molecule known as a super-repressor because it represses the lac operon permanently. Which of these would characterize such a mutant?

Which of the following is a function of the protein called ubiquitin?

Which statement about DNA in one of your brain cells is true?

Transcription factors in eukaryotes usually have DNA-binding domains as well as other domains that are specific for binding other molecules. In general, which of the following would you expect many of them to be able to bind?

Two potential functions that eukaryotic cells perform to regulate transcription are

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Development, Stem Cells, and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition, Nutrition, and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons, Synapses, and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

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