Question 1

Some cancer development is due to misregulation of tumor suppressor genes.Thus a drug to increase the activity of a(n) _______ could be a pharmaceutical target.

Accepted Answer

The answer of Some cancer development is due to misregulation...

Question 2

Which situation is least likely to occur in a non-mutant bacterial cell?

Accepted Answer

A)  β-galactoside permease is produced at very low levels in the absence of lactose. 
B)  β-galactoside transacetylase is produced at very low levels when glucose is abundant. 
C)  β-galactoside transacetylase is produced at high levels when lactose is at a high concentration and glucose is not available. 
D)  β-galactoside transacetylase and β-galactoside are both present in very low concentrations. 
E)  β-galactoside permease is absent when β-galactoside is present at a high concentration. 
A)  β-galactoside permease is produced at very low levels in the absence of lactose. 
B)  β-galactoside transacetylase is produced at very low levels when glucose is abundant. 
C)  β-galactoside transacetylase is produced at high levels when lactose is at a high concentration and glucose is not available. 
D)  β-galactoside transacetylase and β-galactoside are both present in very low concentrations. 
E)  β-galactoside permease is absent when β-galactoside is present at a high concentration.

Question 3

Posttranscriptional control in eukaryotes

Accepted Answer

A)  occurs mainly via methylation and demethylation. 
B)  can only regulate the amount of product, not the type of product. 
C)  takes place only in the nucleus. 
D)  takes place only in the cytoplasm. 
E)  can involve several different types of mechanisms. 
A)  occurs mainly via methylation and demethylation. 
B)  can only regulate the amount of product, not the type of product. 
C)  takes place only in the nucleus. 
D)  takes place only in the cytoplasm. 
E)  can involve several different types of mechanisms.

Question 4

In a hypothetical bacterial operon, genes A, C, and D are expressed when "substance r" is present but not when it is absent.Mutations in gene A cause protein 1 not to be produced, but they only affect production of protein 1.Mutations in gene C cause protein 2 not to be produced.Mutations in gene D cause protein 3 not to be produced.Gene B, which has been shown to be near the other genes, does not code for a protein.Mutations in gene B cause genes A, C, and D to be expressed all the time regardless of the presence or absence of substance r.Gene E produces protein 4.Mutations in gene E (which is not near A, B, C, or D) cause genes A, C, and D to be expressed all the time regardless of the presence or absence of substance r.Is this an inducible or repressible operon?

Accepted Answer

The answer of In a hypothetical bacterial operon, genes A,...

Question 5

Consider the following statement: Histone deacetylases tend to decrease transcription from particular genes.Is it true or false, and for what reason?

Accepted Answer

A)  True, because acetylated histones have higher affinity for DNA 
B)  True, because acetylated histones have lower affinity for DNA 
C)  False, because acetylated histones have higher affinity for DNA 
D)  False, because acetylated histones have lower affinity for DNA 
E)  False, because acetylation status of histones has no bearing on transcription 
A)  True, because acetylated histones have higher affinity for DNA 
B)  True, because acetylated histones have lower affinity for DNA 
C)  False, because acetylated histones have higher affinity for DNA 
D)  False, because acetylated histones have lower affinity for DNA 
E)  False, because acetylation status of histones has no bearing on transcription

Question 6

In a stained preparation of epithelial cells from a female mammal, the highly condensed chromosome observable in interphase nuclei is the inactive X chromosome known as a _______.

Accepted Answer

The answer of In a stained preparation of epithelial cells...

Question 7

Sigma factors bind to

Accepted Answer

A)  promoters with no specificity. 
B)  specific types of promoters. 
C)  repressors. 
D)  co-repressors. 
E)  RNA polymerases. 
A)  promoters with no specificity. 
B)  specific types of promoters. 
C)  repressors. 
D)  co-repressors. 
E)  RNA polymerases.

Question 8

A bacterial gene (gene A) ordinarily makes a protein that binds to DNA.A mutation of gene A causes an increase in the expression of gene B.We can conclude that

Accepted Answer

A)  gene A is a positive regulator of gene B. 
B)  gene A is a negative regulator of gene B. 
C)  gene B is a positive regulator of gene A. 
D)  gene B is a negative regulator of gene A. 
E)  genes A and B regulate each other. 
A)  gene A is a positive regulator of gene B. 
B)  gene A is a negative regulator of gene B. 
C)  gene B is a positive regulator of gene A. 
D)  gene B is a negative regulator of gene A. 
E)  genes A and B regulate each other.

Question 9

When it is on a transcriptionally active X chromosome, Xist will be _______ active and _______ methylated than when it is on a transcriptionally inactive X.

Accepted Answer

A)  more; more 
B)  more; less 
C)  as; more 
D)  less; more 
E)  less; less 
A)  more; more 
B)  more; less 
C)  as; more 
D)  less; more 
E)  less; less

Question 10

If a mutation causes a decrease in the activity of histone acetyltransferases, histones will most likely have a _______ affinity for DNA, and there will be _______ in transcription rates.

Accepted Answer

A)  greater; an increase 
B)  greater; a decrease 
C)  reduced; an increase 
D)  reduced; no change 
E)  reduced; a decrease 
A)  greater; an increase 
B)  greater; a decrease 
C)  reduced; an increase 
D)  reduced; no change 
E)  reduced; a decrease

Question 11

A particular protein binds to DNA and decreases transcription.This is a case of _______ regulation.

Accepted Answer

The answer of A particular protein binds to DNA and...

Question 12

How does regulation of stress response proteins in plants differ from regulation of enzymes produced from a bacterial operon?

Accepted Answer

A)  Expression of stress response proteins is coordinately regulated; expression of bacterial operon genes is not. 
B)  Expression of bacterial operon genes is coordinately regulated; expression of stress response proteins is not. 
C)  Regulation of stress response proteins involves DNA-protein interactions; regulation of bacterial operon genes does not. 
D)  Regulation of bacterial operon genes involves DNA-protein interactions; regulation of stress response proteins does not. 
E)  Stress response genes are found in various locations throughout the plant genome; bacterial operon genes are found in one unit. 
A)  Expression of stress response proteins is coordinately regulated; expression of bacterial operon genes is not. 
B)  Expression of bacterial operon genes is coordinately regulated; expression of stress response proteins is not. 
C)  Regulation of stress response proteins involves DNA-protein interactions; regulation of bacterial operon genes does not. 
D)  Regulation of bacterial operon genes involves DNA-protein interactions; regulation of stress response proteins does not. 
E)  Stress response genes are found in various locations throughout the plant genome; bacterial operon genes are found in one unit.

Question 13

In eukaryotic gene regulation, a(n) _______ is similar in structure but opposite in function to a silencer.

Accepted Answer

A)  inducer 
B)  general transcription factor 
C)  specific transcription factor 
D)  enhancer 
E)  promoter 
A)  inducer 
B)  general transcription factor 
C)  specific transcription factor 
D)  enhancer 
E)  promoter

Question 14

Refer to the figure showing the initiation of transcription in eukaryotes.   From the figure it can be concluded that

Accepted Answer

A)  all transcription factors work alone to initiate transcription. 
B)  some transcription factors bind directly to DNA. 
C)  TFIID binds to the promoter at the TATA box after transcription factors B and F have altered its shape. 
D)  protein-coding genes contain noncoding sequences. 
E)  RNA polymerase II independently binds to the promoter and initiates transcription. 
A)  all transcription factors work alone to initiate transcription. 
B)  some transcription factors bind directly to DNA. 
C)  TFIID binds to the promoter at the TATA box after transcription factors B and F have altered its shape. 
D)  protein-coding genes contain noncoding sequences. 
E)  RNA polymerase II independently binds to the promoter and initiates transcription.

Question 15

The binding of a protein to DNA to increase transcription is a case of _______ regulation.

Accepted Answer

The answer of The binding of a protein to DNA...

Question 16

When the synthesis of an enzyme is turned off in response to an external biochemical cue (such as an excess in tryptophan), the enzyme is said to be _______.

Accepted Answer

The answer of When the synthesis of an enzyme is...

Question 17

The model virus bacteriophage λ (lambda) has been used extensively to study the lysogenic mechanism.The virus genome includes genes that encode the regulator proteins cI and Cro, which compete for specific promotors on the viral DNA-including their own promotors.Cro and cI have opposite effects on each promotor: cI represses the expression of genes involved in the lytic cycle and promotes expression of genes involved in lysogeny, whereas Cro does the opposite.Suppose a mutation in Cro increases its expression.This mutation would make entering lysogeny _______ likely.A mutation that increases the expression of cI would have _______ effect on the likelihood of the virus entering lysogeny.

Accepted Answer

A)  more; a similar 
B)  more; no 
C)  more; the opposite 
D)  less; a similar 
E)  less; the opposite 
A)  more; a similar 
B)  more; no 
C)  more; the opposite 
D)  less; a similar 
E)  less; the opposite

Question 18

Which item is not used by a bacteriophage to generate new viral particles?

Accepted Answer

A)  A promoter sequence that is compatible with the host RNA polymerase 
B)  Genes for proteins that inhibit host transcription 
C)  Genes for capsid proteins 
D)  Nucleases 
E)  Genes for viral RNA polymerase 
A)  A promoter sequence that is compatible with the host RNA polymerase 
B)  Genes for proteins that inhibit host transcription 
C)  Genes for capsid proteins 
D)  Nucleases 
E)  Genes for viral RNA polymerase

Question 19

Inactive X chromosomes in mammals are referred to as

Accepted Answer

A)  CpG islands. 
B)  euchromatin. 
C)  methylation islands. 
D)  acetylation islands. 
E)  Barr bodies. 
A)  CpG islands. 
B)  euchromatin. 
C)  methylation islands. 
D)  acetylation islands. 
E)  Barr bodies.

Question 20

The three basic parts of an operon are the

Accepted Answer

A)  promoter, the operator, and two or more structural genes. 
B)  promoter, the structural genes, and the termination codons. 
C)  promoter, the mRNA, and the termination codons. 
D)  structural genes, the mRNA, and the tRNAs. 
E)  promoter and two structural genes. 
A)  promoter, the operator, and two or more structural genes. 
B)  promoter, the structural genes, and the termination codons. 
C)  promoter, the mRNA, and the termination codons. 
D)  structural genes, the mRNA, and the tRNAs. 
E)  promoter and two structural genes.

Exam 16: Regulation of Gene Expression

Some cancer development is due to misregulation of tumor suppressor genes.Thus a drug to increase the activity of a(n) _______ could be a pharmaceutical target.

Which situation is least likely to occur in a non-mutant bacterial cell?

Posttranscriptional control in eukaryotes

Consider the following statement: Histone deacetylases tend to decrease transcription from particular genes.Is it true or false, and for what reason?

In a stained preparation of epithelial cells from a female mammal, the highly condensed chromosome observable in interphase nuclei is the inactive X chromosome known as a _______.

Sigma factors bind to

A bacterial gene (gene A) ordinarily makes a protein that binds to DNA.A mutation of gene A causes an increase in the expression of gene B.We can conclude that

When it is on a transcriptionally active X chromosome, Xist will be _______ active and _______ methylated than when it is on a transcriptionally inactive X.

If a mutation causes a decrease in the activity of histone acetyltransferases, histones will most likely have a _______ affinity for DNA, and there will be _______ in transcription rates.

A particular protein binds to DNA and decreases transcription.This is a case of _______ regulation.

How does regulation of stress response proteins in plants differ from regulation of enzymes produced from a bacterial operon?

In eukaryotic gene regulation, a(n) _______ is similar in structure but opposite in function to a silencer.

Refer to the figure showing the initiation of transcription in eukaryotes. From the figure it can be concluded that

The binding of a protein to DNA to increase transcription is a case of _______ regulation.

When the synthesis of an enzyme is turned off in response to an external biochemical cue (such as an excess in tryptophan), the enzyme is said to be _______.

Which item is not used by a bacteriophage to generate new viral particles?

Inactive X chromosomes in mammals are referred to as

The three basic parts of an operon are the

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When it is on a transcriptionally active X chromosome, Xist will be _ active and _ methylated than when it is on a transcriptionally inactive X.

If a mutation causes a decrease in the activity of histone acetyltransferases, histones will most likely have a _ affinity for DNA, and there will be _ in transcription rates.