Question 1

If the genetically engineered albino mice were given no special treatment,how would the tyrosinase gene be expressed?

Accepted Answer

A) It would not be transcribed. 
B) It would be transcribed to a moderate level. 
C) It would be transcribed to a high level. 
A) It would not be transcribed. 
B) It would be transcribed to a moderate level. 
C) It would be transcribed to a high level. A

Question 2

A compound known as X-Gal is widely used in molecular genetic research.When wild-type (normal)E.coli is grown on medium containing X-Gal,the bacterial colonies turn blue.In contrast,when lacZ mutants are grown on medium containing X-Gal,the bacterial colonies remain their normal white color.What is X-Gal likely to be?

Accepted Answer

A) a compound chemically similar to glucose 
B) a compound chemically similar to galactose 
C) a compound chemically similar to lactose 
D) a compound that cannot be transported into lacZ mutants 
E) a compound that can only be transported into lacA mutants 
A) a compound chemically similar to glucose 
B) a compound chemically similar to galactose 
C) a compound chemically similar to lactose 
D) a compound that cannot be transported into lacZ mutants 
E) a compound that can only be transported into lacA mutants C

Question 3

Although the expression of most genes is tightly regulated,some genes are expressed at roughly constant rates (i.e.,constitutively).Which of the following genes would you predict to be constitutively expressed?

Accepted Answer

A) genes involved in the biosynthesis of the amino acid tryptophan 
B) genes involved in the degradation of tryptophan 
C) genes involved in the degradation of arabinose,a sugar 
D) genes that code for ribosomal RNAs 
E) genes involved in the transport of the sugar maltose 
A) genes involved in the biosynthesis of the amino acid tryptophan 
B) genes involved in the degradation of tryptophan 
C) genes involved in the degradation of arabinose,a sugar 
D) genes that code for ribosomal RNAs 
E) genes involved in the transport of the sugar maltose D

Question 4

Recall from Chapter 11 that cyclin-dependent kinases are activated when they bind to a cyclin protein.This form of regulation is

Accepted Answer

A) constitutive control. 
B) transcriptional control. 
C) translational control. 
D) post-translational control. 
A) constitutive control. 
B) transcriptional control. 
C) translational control. 
D) post-translational control.

Question 5

E.coli adenylyl cyclase is most active when

Accepted Answer

A) extracellular glucose levels are low. 
B) intracellular levels of lactose are low. 
C) intracellular levels of lactose are high. 
D) intracellular levels of cAMP are high. 
A) extracellular glucose levels are low. 
B) intracellular levels of lactose are low. 
C) intracellular levels of lactose are high. 
D) intracellular levels of cAMP are high.

Question 6

Imagine that you've run a DNA footprinting analysis.Many closely spaced bands (DNA fragments)are seen in the lane of the gel prepared from DNA without protein.In the adjacent lane prepared from DNA mixed with protein,a subset of the bands is seen,but there is a large region where no bands are observed.This empty region represents

Accepted Answer

A) the region where protein did not bind to DNA. 
B) the region where protein bound to DNA. 
C) a region where there was no DNA for protein binding. 
D) a region where protein was digested by the enzyme. 
A) the region where protein did not bind to DNA. 
B) the region where protein bound to DNA. 
C) a region where there was no DNA for protein binding. 
D) a region where protein was digested by the enzyme.

Question 7

A group of genes that are regulated together and transcribed into a single mRNA is

Accepted Answer

A) an intron. 
B) an operon. 
C) a repressor. 
D) an activator. 
E) an inducer. 
A) an intron. 
B) an operon. 
C) a repressor. 
D) an activator. 
E) an inducer.

Question 8

How does a regulatory protein that binds to a specific DNA sequence recognize this sequence?

Accepted Answer

A) The regulatory protein opens up the two strands of DNA and detects the bases on one of the strands. 
B) The regulatory protein opens up the two strands of DNA and detects the bases on both strands. 
C) The regulatory protein detects the portions of the base pairs that project into the grooves of double-stranded DNA. 
D) The regulatory protein detects specific sequences in the sugar-phosphate backbone of one of the DNA strands. 
E) The regulatory protein detects specific sequences in the sugar-phosphate backbone of both of the DNA strands. 
A) The regulatory protein opens up the two strands of DNA and detects the bases on one of the strands. 
B) The regulatory protein opens up the two strands of DNA and detects the bases on both strands. 
C) The regulatory protein detects the portions of the base pairs that project into the grooves of double-stranded DNA. 
D) The regulatory protein detects specific sequences in the sugar-phosphate backbone of one of the DNA strands. 
E) The regulatory protein detects specific sequences in the sugar-phosphate backbone of both of the DNA strands.

Question 9

Imagine that you've added the same indicator used by Monod to E.coli colonies growing on a plate with glucose and no lactose.One colony is yellow and the remainders are white.This result suggests that cells of the yellow colony

Accepted Answer

A) have constitutively active lacZ and lacY genes. 
B) cannot activate either the lacZ or lacY gene. 
C) can activate the lacY gene but cannot active the lacZ gene. 
D) cannot metabolize lactose. 
E) cannot transport lactose into the cell. 
A) have constitutively active lacZ and lacY genes. 
B) cannot activate either the lacZ or lacY gene. 
C) can activate the lacY gene but cannot active the lacZ gene. 
D) cannot metabolize lactose. 
E) cannot transport lactose into the cell.

Question 10

How does the inducer change the repressor's affinity for DNA?

Accepted Answer

A) Inducer binding changes the repressor's shape so that the promoter is bent from a rectangular to a loop-like shape. 
B) Inducer binding changes the repressor's shape to alter the positioning of the repressor's DNA binding domains so they no longer interact with DNA. 
C) Inducer binding makes the repressor's DNA binding domains more positively charged,so they can no longer bind the operator. 
D) Inducer binding makes the repressor's DNA binding domains more negatively charged,so they can no longer bind the operator. 
A) Inducer binding changes the repressor's shape so that the promoter is bent from a rectangular to a loop-like shape. 
B) Inducer binding changes the repressor's shape to alter the positioning of the repressor's DNA binding domains so they no longer interact with DNA. 
C) Inducer binding makes the repressor's DNA binding domains more positively charged,so they can no longer bind the operator. 
D) Inducer binding makes the repressor's DNA binding domains more negatively charged,so they can no longer bind the operator.

Question 11

The product of the lacI gene is most like a car's

Accepted Answer

A) parking brake. 
B) accelerator pedal. 
C) steering wheel. 
D) engine. 
E) wheels. 
A) parking brake. 
B) accelerator pedal. 
C) steering wheel. 
D) engine. 
E) wheels.

Question 12

How did Cronin et al.activate expression of tyrosinase to change the color of a white (albino)mouse to brown?

Accepted Answer

A) They exercised the mice vigorously. 
B) They fed the mice a diet rich in glucose. 
C) They added IPTG,a lactose analogue,to the drinking water. 
D) They added cAMP to the drinking water. 
A) They exercised the mice vigorously. 
B) They fed the mice a diet rich in glucose. 
C) They added IPTG,a lactose analogue,to the drinking water. 
D) They added cAMP to the drinking water.

Question 13

Bacterial and eukaryotic cells primarily control gene expression at the level of transcription.If instead cells exerted control of gene expression primarily at the post-translational level,what would be different?

Accepted Answer

A) The ability to rapidly respond to environmental change would be reduced. 
B) Cells would expend significantly more energy. 
C) Genes would no longer be transcribed. 
D) Translation of mRNA into protein would not occur. 
A) The ability to rapidly respond to environmental change would be reduced. 
B) Cells would expend significantly more energy. 
C) Genes would no longer be transcribed. 
D) Translation of mRNA into protein would not occur.

Question 14

The trp repressor blocks transcription of the trp operon when the repressor

Accepted Answer

A) binds to inducer. 
B) is not bound to inducer. 
C) binds to tryptophan. 
D) is not bound to tryptophan. 
E) is not bound to the operator. 
A) binds to inducer. 
B) is not bound to inducer. 
C) binds to tryptophan. 
D) is not bound to tryptophan. 
E) is not bound to the operator.

Question 15

An E.coli cell without a functional lacI gene is expected to

Accepted Answer

A) never produce β-galactosidase. 
B) always produce β-galactosidase. 
C) be unable to transport lactose into the cell. 
D) be unable to metabolize lactose within the cell. 
A) never produce β-galactosidase. 
B) always produce β-galactosidase. 
C) be unable to transport lactose into the cell. 
D) be unable to metabolize lactose within the cell.

Question 16

Imagine that you've set up a genetic screen to identify E.coli mutants that cannot metabolize the amino acid tryptophan.Beginning with a master plate containing many colonies,you prepare replica plates on medium with glucose or tryptophan as the only energy source.You would look for colonies that

Accepted Answer

A) cannot grow on either type of media. 
B) can grow on both types of media. 
C) can grow only on the plates with tryptophan. 
D) can grow only on the plates with glucose. 
A) cannot grow on either type of media. 
B) can grow on both types of media. 
C) can grow only on the plates with tryptophan. 
D) can grow only on the plates with glucose.

Question 17

A technique that can be used to identify mutant bacterial cells is called

Accepted Answer

A)  indicator plating. 
B) replica plating. 
C) master plating. 
D) comparison plating. 
A)  indicator plating. 
B) replica plating. 
C) master plating. 
D) comparison plating.

Question 18

Full induction of the lac operon occurs when

Accepted Answer

A) lactose levels are low and glucose levels are low. 
B) lactose levels are low and glucose levels are high. 
C) lactose levels are high and glucose levels are low. 
D) lactose levels are high and glucose levels are high. 
A) lactose levels are low and glucose levels are low. 
B) lactose levels are low and glucose levels are high. 
C) lactose levels are high and glucose levels are low. 
D) lactose levels are high and glucose levels are high.

Question 19

Extracellular glucose inhibits transcription of the lac operon by

Accepted Answer

A) strengthening the binding of repressor to the operator. 
B) weakening the binding of repressor to the operator. 
C) inhibiting RNA polymerase from opening the strands of DNA to initiate transcription. 
D) reducing the levels of intracellular cAMP. 
E) activating adenylyl cyclase. 
A) strengthening the binding of repressor to the operator. 
B) weakening the binding of repressor to the operator. 
C) inhibiting RNA polymerase from opening the strands of DNA to initiate transcription. 
D) reducing the levels of intracellular cAMP. 
E) activating adenylyl cyclase.

Question 20

To date,several lactose metabolism mutants have been found in Escherichia coli.One of these mutants has a phenotype in which the cell cannot accumulate lactose because no lactose permease protein is present.What genotype would be associated with this mutation?

Accepted Answer

A) lacZ⁻ 
B) lacY⁻ 
C) lacI⁻ 
A) lacZ⁻ 
B) lacY⁻ 
C) lacI⁻

Exam 17: Control of Gene Expression in Bacteria

If the genetically engineered albino mice were given no special treatment,how would the tyrosinase gene be expressed?

Although the expression of most genes is tightly regulated,some genes are expressed at roughly constant rates (i.e.,constitutively).Which of the following genes would you predict to be constitutively expressed?

Recall from Chapter 11 that cyclin-dependent kinases are activated when they bind to a cyclin protein.This form of regulation is

E.coli adenylyl cyclase is most active when

A group of genes that are regulated together and transcribed into a single mRNA is

How does a regulatory protein that binds to a specific DNA sequence recognize this sequence?

Imagine that you've added the same indicator used by Monod to E.coli colonies growing on a plate with glucose and no lactose.One colony is yellow and the remainders are white.This result suggests that cells of the yellow colony

How does the inducer change the repressor's affinity for DNA?

The product of the lacI gene is most like a car's

How did Cronin et al.activate expression of tyrosinase to change the color of a white (albino)mouse to brown?

Bacterial and eukaryotic cells primarily control gene expression at the level of transcription.If instead cells exerted control of gene expression primarily at the post-translational level,what would be different?

The trp repressor blocks transcription of the trp operon when the repressor

An E.coli cell without a functional lacI gene is expected to

Imagine that you've set up a genetic screen to identify E.coli mutants that cannot metabolize the amino acid tryptophan.Beginning with a master plate containing many colonies,you prepare replica plates on medium with glucose or tryptophan as the only energy source.You would look for colonies that

A technique that can be used to identify mutant bacterial cells is called

Full induction of the lac operon occurs when

Extracellular glucose inhibits transcription of the lac operon by

To date,several lactose metabolism mutants have been found in Escherichia coli.One of these mutants has a phenotype in which the cell cannot accumulate lactose because no lactose permease protein is present.What genotype would be associated with this mutation?

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Lipids, membranes, and the First Cells

Inside the Cell

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Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, RNA Processing, and Translation

Control of Gene Expression in Eukaryotes

Analyzing and Engineering Genes

Genomics

Principles of Development

An Introduction to Animal Development

An Introduction to Plant Development

Evolution by Natural Selection

Evolutionary Processes

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Phylogenies and the History of Life

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Water and Electrolyte Balance in Animals

Animal Nutrition

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Electrical Signals in Animals

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