Question 1

For a repressible operon to be transcribed, which of the following conditions must occur?

Accepted Answer

A)   RNA polymerase must bind to the promoter and a corepressor must be present.
B)   RNA polymerase and active repressor must occupy the promoter.
C)   RNA polymerase must bind to the promoter, and the repressor must be inactive.
D)   RNA polymerase must bind the inducer, and the repressor must be inactive.E) A) and D)
F) All of the above

Question 2

The product of the bicoid gene in Drosophila is responsible for determining which of the following embryonic features or structures during development?

Accepted Answer

A)   orientation of the dorsal-ventral axis
B)   orientation of the left-right axis
C)   segmentation of developing limbs
D)   orientation of the anterior-posterior axisE) B) and D)
F) B) and C)

Question 3

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.E) C) and D)
F) None of the above

Question 4

Cytoplasmic determinants are best described as having which of the following characteristics?

Accepted Answer

A)   They are maternal substances in the egg that influence the course of early development.
B)   They are single-stranded RNA molecules capable of binding complementary sequences and altering translation.
C)   They are centromeric regions of DNA loosened for chromosomal replication by transcription factors.
D)   They are tissue-specific transcription factors expressed in the early embryo.E) B) and D)
F) None of the above

Question 5

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 RNA polymerase
D)   when the repressor is not bound to the operatorE) A) and D)
F) B) and C)

Question 6

Which of the following is the most likely phenotypes of a yeast mutant that contains histones that are resistant to acetylation?

Accepted Answer

A)   The mutant will grow rapidly.
B)   The mutant will require galactose for growth.
C)   The mutant will show decreased levels of gene expression.
D)   The mutant will show increased levels of gene expression.E) A) and C)
F) None of the above

Question 7

Mutations in which of the following genes result in transformations in the identity of entire body parts?

Accepted Answer

A)   segmentation genes
B)   egg-polarity genes
C)   homeotic genes
D)   inducersE) None of the above
F) C) and D)

Question 8

Which of the following functions are characteristic of general transcription factors in eukaryotes?

Accepted Answer

A)   They bind to other proteins or to the TATA box.
B)   They inhibit RNA polymerase binding to the promoter and begin transcribing.
C)   They are sufficient to allow high levels of transcription.
D)   They bind to sequences just after the start site of transcription.E) None of the above
F) All of the above

Question 9

Which of the following processes is the best way to determine whether alternative splicing of a given gene occurs?

Accepted Answer

A)   Compare the size of the DNA within the given gene and a similar gene in a related organism.
B)   Compare the sequences of the given gene and a gene known to undergo alternative splicing.
C)   Isolate the primary transcripts made from the given gene and compare the sequences.
D)   Isolate mRNA from the given gene and compare the sequences.E) A) and D)
F) None of the above

Question 10

Which of the following is a molecule that helps to "turn off" the expression of genes in a cell?

Accepted Answer

A)   operator
B)   inducer
C)   promoter
D)   corepressorE) A) and C)
F) None of the above

Question 11

Which of the following describes how steroid hormones regulate gene expression?

Accepted Answer

A)   They bind to control elements in a regulatory gene and promote synthesis of that operon.
B)   They activate translation of certain mRNAs.
C)   They promote the degradation of specific mRNAs.
D)   They bind to intracellular receptors and alter transcription of specific genes.E) B) and C)
F) All of the above

Question 12

A mutation in E. coli results in a molecule known as a "super-repressor" because the operon is permanently repressed. Which of the following describes the most likely effect of the mutation on the repressor protein?

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 a repressor that binds CAP.E) None of the above
F) All of the above

Question 13

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)   It is the same as the DNA in one of your liver cells.
D)   Each gene lies immediately adjacent to an enhancer.E) A) and B)
F) B) and C)

Question 14

Which of the following characteristics of gene expression allows bacteria to quickly change protein synthesis patterns 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 when it is needed later.
D)   Operons are activated in the presence of transcription factors.E) A) and B)
F) None of the above

Question 15

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

Accepted Answer

A)   Environmental signals entering the cell cause the genes to rearrange into related sets.
B)   Groups of genes that are expressed together have specific combinations of control elements.
C)   Related genes are organized in operons that share a promoter that controls their expression.
D)   Release of each gene's individual inducing molecule must be coordinated to coordinate gene expression.E) A) and D)
F) B) and C)

Question 16

Which of the following processes destroys RNA molecules 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 disposalE) A) and B)
F) A) and C)

Question 17

How does breakdown of 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 cAMPE) A) and C)
F) B) and D)

Question 18

Much of the human genome does not code for proteins. Which of the following types of DNA are found in these regions of the genome?

Accepted Answer

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

Question 19

Which of the following molecules is a protein produced by a regulatory gene?

Accepted Answer

A)   operon
B)   operator
C)   promoter
D)   repressorE) A) and D)
F) All of the above

Question 20

Prokaryote's ability to regulate patterns of gene expression most likely promotes the organism's survival by ________.

Accepted Answer

A)   organizing gene expression, so that genes are expressed in a given order
B)   allowing each gene to be expressed an equal number of times
C)   allowing an organism to adjust to changes in environmental conditions
D)   allowing environmental changes to alter a prokaryote's genomeE) B) and C)
F) C) and D)

Exam 18: Control of Gene Expression

Which of the following processes is the best way to determine whether alternative splicing of a given gene occurs?

Correct AnswerverifiedShow Answer

Which of the following describes how steroid hormones regulate gene expression?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

The product of the bicoid gene in Drosophila is responsible for determining which of the following embryonic features or structures during development?

Correct AnswerverifiedShow Answer

Which of the following is the most likely phenotypes of a yeast mutant that contains histones that are resistant to acetylation?

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

Mutations in which of the following genes result in transformations in the identity of entire body parts?

Correct AnswerverifiedShow Answer

Which of the following functions are characteristic of general transcription factors in eukaryotes?

Correct AnswerverifiedShow Answer

Which of the following is a molecule that helps to "turn off" the expression of genes in a cell?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following molecules is a protein produced by a regulatory gene?

Correct AnswerverifiedShow Answer

For a repressible operon to be transcribed, which of the following conditions must occur?

Correct AnswerverifiedShow Answer

Much of the human genome does not code for proteins. Which of the following types of DNA are found in these regions of the genome?

Correct AnswerverifiedShow Answer

Prokaryote's ability to regulate patterns of gene expression most likely promotes the organism's survival by ________.

Correct AnswerverifiedShow Answer

How does breakdown of glucose inhibit transcription of the lac operon?

Correct AnswerverifiedShow Answer

Which of the following characteristics of gene expression allows bacteria to quickly change protein synthesis patterns in response to environmental changes?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Cytoplasmic determinants are best described as having which of the following characteristics?

Correct AnswerverifiedShow Answer

A mutation in E. coli results in a molecule known as a "super-repressor" because the operon is permanently repressed. Which of the following describes the most likely effect of the mutation on the repressor protein?

Correct AnswerverifiedShow Answer

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