Question 1

How does the transcription of structural genes in an inducible operon occur?

Accepted Answer

A)   It occurs continuously in the cell.
B)   It starts when the pathway's substrate is present.
C)   It starts when the pathway's product is present.
D)   It stops when the pathway's product is present.

Question 2

What essential information does the product of the bicoid gene in Drosophila provide during development?

Accepted Answer

A)   orientation of the dorsal-ventral axis
B)   orientation of the left-right axis
C)   segmentation
D)   orientation of the anterior-posterior axis

Question 3

Which of the following statements describes a cell that is considered to be differentiated?

Accepted Answer

A)   The cell replicates by the process of mitosis.
B)   The cell loses connections to the surrounding cells.
C)   The cell produces proteins specific to a particular cell type.
D)   The cell appears to be different from the surrounding cells.

Question 4

Which of the following molecules helps to "turn off" genes in a cell?

Accepted Answer

A)   operon
B)   inducer
C)   promoter
D)   corepressor

Question 5

Which of the following statements correctly describes the primary difference between enhancers and proximal control elements?

Accepted Answer

A)   Enhancers are transcription factors; proximal control elements are DNA sequences.
B)   Enhancers improve transcription; proximal control elements inhibit transcription.
C)   Enhancers are located considerable distances from the promoter; proximal control elements are close to the promoter.
D)   Enhancers are DNA sequences; proximal control elements are proteins.

Question 6

Why are BRCA1 and BRCA2 considered to be tumor-suppressor genes?

Accepted Answer

A)   Their normal products participate in repair of DNA damage.
B)   The mutant forms of either one of these prevent breast cancer.
C)   The normal genes make estrogen receptors.
D)   They block penetration of breast cells by chemical carcinogens.

Question 7

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. Many people were surprised that the number of protein-coding sequences was much smaller than they had expected. Which of the following types of DNA make up the rest of the human genome?

Accepted Answer

A)   DNA that consists of histone coding sequences
B)   DNA that is translated directly without being transcribed
C)   non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function
D)   non-protein-coding DNA that serves as binding sites for reverse transcriptase

Question 8

Which of the following types of mutation would convert a proto-oncogene into an oncogene?

Accepted Answer

A)   a mutation that blocks transcription of the proto-oncogene
B)   a mutation that creates an unstable proto-oncogene mRNA
C)   a mutation that greatly increases the amount of the proto-oncogene protein
D)   a deletion of most of the proto-oncogene coding sequence

Question 9

Which of the following molecules are involved in pattern formation during development?

Accepted Answer

A)   cytoplasmic determinants
B)   miRNAs
C)   cAMP
D)   transcription factors

Question 10

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 increasing acetylation of histone tails in the chromatin of the cells. Which of the following results would she most likely see in these cells?

Accepted Answer

A)   increased chromatin condensation
B)   decreased chromatin condensation
C)   decreased binding of transcription factors
D)   inactivation of the selected genes

Question 11

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If a researcher moves the operator to the far end of the operon, past the transacetylase (lacA) gene, which of the following processes would likely occur when the cell is exposed to lactose?

Accepted Answer

A)   The inducer will no longer bind to the repressor.
B)   The repressor will no longer bind to the operator.
C)   The operon will never be transcribed.
D)   The genes of the lac operon will be transcribed continuously.

Question 12

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

Accepted Answer

A)   Proto-oncogenes first arose from viral infections.
B)   Proto-oncogenes are mutant versions of normal genes.
C)   Proto-oncogenes are genetic "junk."
D)   Proto-oncogenes normally help regulate cell division.

Question 13

When the Bicoid protein is expressed in Drosophila, divisions between cells in the embryo are not yet fully developed. This information helps to explain which observation by Nüsslein-Volhard and Wieschaus?

Accepted Answer

A)   mRNA from the egg is translated into the Bicoid protein.
B)   Bicoid protein diffuses throughout the embryo in a concentration gradient.
C)   Bicoid protein serves as a transcription regulator.
D)   Bicoid protein determines the dorso-ventral axis of the embryo.

Question 14

How does extracellular glucose inhibit transcription of the lac operon?

Accepted Answer

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

Question 15

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

Accepted Answer

A)   irreversible binding of the repressor to the promoter
B)   reduced transcription of the operon's genes
C)   buildup of a substrate for the pathway controlled by the operon
D)   continuous transcription of the operon's genes

Question 16

Under what conditions does the trp repressor block transcription of the trp operon?

Accepted Answer

A)   when the repressor binds to the inducer
B)   when the repressor binds to tryptophan
C)   when the repressor is not bound to tryptophan
D)   when the repressor is not bound to the operator

Question 17

Which of the following processes destroys RNA molecules in a cell if they have a sequence complementary to an introduced double-stranded RNA?

Accepted Answer

A)   RNA interference
B)   RNA obstruction
C)   RNA blocking
D)   RNA disposal

Question 18

In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. 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)   genes of the bacteria, which are abundant in the colon

Question 19

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.

Question 20

How are bacteria able to change their patterns of protein synthesis so quickly in response to environmental changes?

Accepted Answer

A)   mRNAs that are produced are short-lived and degraded within a few minutes of being synthesized.
B)   mRNA have long lifespans, allowing the bacteria to use them many times for translation.
C)   mRNA is stored for later use.
D)   Operons are activated in the presence of transcription factors.

Exam 18: Regulation of Gene Expression

What essential information does the product of the bicoid gene in Drosophila provide during development?

Correct Answer
verified

Why are BRCA1 and BRCA2 considered to be tumor-suppressor genes?

Correct Answer
verified

Correct Answer
verified

How does extracellular glucose inhibit transcription of the lac operon?

Correct Answer
verified

How are bacteria able to change their patterns of protein synthesis so quickly in response to environmental changes?

Correct Answer
verified

Which of the following types of mutation would convert a proto-oncogene into an oncogene?

Correct Answer
verified

Correct Answer
verified

Which of the following processes destroys RNA molecules in a cell if they have a sequence complementary to an introduced double-stranded RNA?

Correct Answer
verified

Correct Answer
verified

Which of the following molecules are involved in pattern formation during development?

Correct Answer
verified

Muscle cells differ from nerve cells mainly because they

Correct Answer
verified

Which of the following statements describes a cell that is considered to be differentiated?

Correct Answer
verified

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

Correct Answer
verified

How does the transcription of structural genes in an inducible operon occur?

Correct Answer
verified

Which of the following molecules helps to "turn off" genes in a cell?

Correct Answer
verified

In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?

Correct Answer
verified

Under what conditions does the trp repressor block transcription of the trp operon?

Correct Answer
verified

Which of the following statements correctly describes the primary difference between enhancers and proximal control elements?

Correct Answer
verified

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

Correct Answer
verified

When the Bicoid protein is expressed in Drosophila, divisions between cells in the embryo are not yet fully developed. This information helps to explain which observation by Nüsslein-Volhard and Wieschaus?

Correct Answer
verified

Exam 18: Regulation of Gene Expression

What essential information does the product of the bicoid gene in Drosophila provide during development?

Correct AnswerverifiedShow Answer

Why are BRCA1 and BRCA2 considered to be tumor-suppressor genes?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

How does extracellular glucose inhibit transcription of the lac operon?

Correct AnswerverifiedShow Answer

How are bacteria able to change their patterns of protein synthesis so quickly in response to environmental changes?

Correct AnswerverifiedShow Answer

Which of the following types of mutation would convert a proto-oncogene into an oncogene?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which of the following processes destroys RNA molecules in a cell if they have a sequence complementary to an introduced double-stranded RNA?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which of the following molecules are involved in pattern formation during development?

Correct AnswerverifiedShow Answer

Muscle cells differ from nerve cells mainly because they

Correct AnswerverifiedShow Answer

Which of the following statements describes a cell that is considered to be differentiated?

Correct AnswerverifiedShow Answer

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

Correct AnswerverifiedShow Answer

How does the transcription of structural genes in an inducible operon occur?

Correct AnswerverifiedShow Answer

Which of the following molecules helps to "turn off" genes in a cell?

Correct AnswerverifiedShow Answer

In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?

Correct AnswerverifiedShow Answer

Under what conditions does the trp repressor block transcription of the trp operon?

Correct AnswerverifiedShow Answer

Which of the following statements correctly describes the primary difference between enhancers and proximal control elements?

Correct AnswerverifiedShow Answer

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

Correct AnswerverifiedShow Answer

When the Bicoid protein is expressed in Drosophila, divisions between cells in the embryo are not yet fully developed. This information helps to explain which observation by Nüsslein-Volhard and Wieschaus?

Correct AnswerverifiedShow Answer

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