Question 1

A point mutation in the operator of the lac operon would most likely cause

Accepted Answer

A)   no transcription of the lactose metabolizing genes, even when lactose is absent.
B)   no transcription of the lactose metabolizing genes, even when lactose is present.
C)   no binding of the repressor protein to the operator even when lactose is absent.
D)   binding of the repressor protein to the regulatory gene in both the presence and absence of lactose.
E)   no transcription of the regulatory gene, even in the presence of lactose.F) A) and E)
G) A) and D)

Question 2

Proteins are active immediately after translation occurs.

Accepted Answer

A) True 
 B)False  False

Question 3

A tumor suppressor gene undergoes a mutation that causes it to lose its normal function. What would be the most likely result of this mutation?

Accepted Answer

A)   The cell cycle halts and reverses back to the G0 stage.
B)   The cell undergoes contact inhibition even when it is not surrounded by other cells.
C)   The cell cycle accelerates.
D)   The cell no longer responds to signals that cause it to stop dividing or undergo apoptosis.
E)   The cell stops dividing permanently and will never re-enter the cell cycle.F) C) and D)
G) C) and E)

Question 4

Why do adult stem cells currently have fewer uses in therapeutic cloning than embryonic stem cells?

Accepted Answer

A)   Embryonic stem cells have longer telomeres and persist for much longer than adult stem cells.
B)   Embryonic stem cells are capable of reverting to a G0 stage when starved.
C)   Adult stem cells may become any type of cell, whereas embryonic stem cells may only become adult stem cells first.
D)   Embryonic stem cells may become any type of cell, whereas adult stem cells may only become a limited number of cell types.
E)   Adult stem cells have more restrictions that prevent them from re-entering the cell cycle at the G0 stage.F) B) and D)
G) C) and D)

Question 5

Proto-oncogenes function by preventing cells from dividing uncontrollably.

Accepted Answer

A) True 
 B)False

Question 6

Heterochromatin differs from euchromatin in that heterochromatin

Accepted Answer

A)   is transcriptionally active, whereas euchromatin is not.
B)   is not found in Barr bodies.
C)   is transcriptionally inactive.
D)   is the result of the unpacking of euchromatin.
E)   contains DNA with accessible promoters.F) C) and D)
G) A) and D)

Question 7

Cancer will occur if one copy of a mutant tumor suppressor gene is inherited.

Accepted Answer

A) True 
 B)False

Question 8

Transcription of the genes of the lac operon is ______ unless _______ is _______.

Accepted Answer

A)   on; lactose; present
B)   off; lactose; absent
C)   off; repressor; absent
D)   on; lactose; absent
E)   off; lactose; presentF) A) and E)
G) D) and E)

Question 9

Many growth factors are classified as which of the following?

Accepted Answer

A)   oncogenes
B)   proto-oncogenes
C)   tumor suppressors
D)   mutant tumor suppressors
E)   signal transduction pathway proteinsF) C) and E)
G) All of the above

Question 10

In eukaryotes, one gene may specify the construction of several proteins.

Accepted Answer

A) True 
 B)False

Question 11

If the maternal X chromosome is inactive and seen as Barr body in one cell, then it is the maternal X chromosome that is inactive and seen as a Barr body in every cell of that woman's body.

Accepted Answer

A) True 
 B)False

Question 12

A woman inherits a mutant BRCA1 allele from her mother. She has an increased risk of developing breast cancer because

Accepted Answer

A)   every cell in the woman's body has a copy of the mutant BRCA1 allele.
B)   she still has one normal allele of the BRCA1 gene that can make up for the loss of function in the mutant allele.
C)   some of the cells in her body are already cancerous, meaning that no further mutations are needed for a tumor to form.
D)   the normal BRCA1 allele is more likely to mutate than in an individual without a mutant BRCA1 allele.
E)   a mutation in her normal BRCA1 allele may lead to cancer, whereas a normal individual would have to acquire two mutations (one in each allele)  to develop cancer.F) A) and B)
G) B) and C)

Question 13

Specialized cells differ from one another because

Accepted Answer

A)   they only express certain genes.
B)   they express all genes.
C)   they turn off gene expression once specialized.
D)   they may re-enter the cell cycle at any time.
E)   they do not express housekeeping genes.F) A) and E)
G) B) and D) A

Question 14

In the absence of lactose,

Accepted Answer

A)   the repressor binds to the operator, and the genes of the lac operon are transcribed.
B)   the repressor binds to the operator, and the genes of the lac operon are not transcribed.
C)   the repressor is unable to bind to the operator, and the genes of the lac operon are transcribed.
D)   the repressor is unable to bind to the operator, and the genes of the lac operon are not transcribed.
E)   the repressor is unable to bind to the operator, and the regulatory gene is transcribed.F) A) and E)
G) A) and D)

Question 15

A(n)  ___ is to reproductive cloning as a(n)  ___ is to therapeutic cloning.

Accepted Answer

A)   specialized cell; clone
B)   clone; enucleated egg
C)   clone; specialized cell
D)   embryonic stem cell; adult stem cell
E)   enucleated egg; specialized cellF) A) and B)
G) A) and C) C

Question 16

Angiogenesis contributes to carcinogenesis because

Accepted Answer

A)   it allows tumor cells to spread to other parts of the body.
B)   it causes blood vessels to grow into the tumor.
C)   it allows tumor cells to invade underlying tissues.
D)   it causes additional mutations to occur in tumor cells.
E)   it causes apoptosis in tumor cells.F) B) and D)
G) A) and C)

Question 17

If tumor cells have a faulty, non-functional proteinase, they will be unable to undergo which of the following processes?

Accepted Answer

A)   mitosis
B)   mutations
C)   metastasis
D)   apoptosis
E)   angiogenesisF) None of the above
G) A) and B)

Question 18

Why is it necessary to "starve" the donor cells prior to reproductive cloning?

Accepted Answer

A)   to force the cells into G0 stage so that the nuclei removed from them will respond to cytoplasmic growth signals
B)   to force the enucleated egg cell into G0 stage so that it would accept the donor nucleus
C)   to lengthen the telomeres in the donor nucleus
D)   to make the nucleus "start over" in the S stage so that the nucleus will be diploid
E)   to make the nucleus "start over" in the S stage so that the nucleus will be haploidF) C) and D)
G) All of the above

Question 19

In the regulation of the lac operon, when lactose is present,

Accepted Answer

A)   lactose binds to the repressor, making it unable to bind to the operator and allowing transcription to proceed.
B)   lactose binds to the operator, making the repressor unable to bind to the operator and allowing transcription to proceed.
C)   the repressor binds to the operator, allowing transcription to proceed.
D)   lactose binds to RNA polymerase, allowing transcription to proceed even in the presence of the repressor.
E)   lactose binds to the repressor, causing it to bind to the operator and allowing transcription to proceed.F) B) and E)
G) All of the above

Question 20

Signal transduction pathways can stimulate transcription activators.

Accepted Answer

A) True 
 B)False

Exam 12: Gene Regulation and Cancer

A point mutation in the operator of the lac operon would most likely cause

Correct AnswerverifiedShow Answer

Proteins are active immediately after translation occurs.

Correct AnswerverifiedFalse

A tumor suppressor gene undergoes a mutation that causes it to lose its normal function. What would be the most likely result of this mutation?

Correct AnswerverifiedShow Answer

Why do adult stem cells currently have fewer uses in therapeutic cloning than embryonic stem cells?

Correct AnswerverifiedShow Answer

Proto-oncogenes function by preventing cells from dividing uncontrollably.

Correct AnswerverifiedShow Answer

Heterochromatin differs from euchromatin in that heterochromatin

Correct AnswerverifiedShow Answer

Cancer will occur if one copy of a mutant tumor suppressor gene is inherited.

Correct AnswerverifiedShow Answer

Transcription of the genes of the lac operon is ______ unless _______ is _______.

Correct AnswerverifiedShow Answer

Many growth factors are classified as which of the following?

Correct AnswerverifiedShow Answer

In eukaryotes, one gene may specify the construction of several proteins.

Correct AnswerverifiedShow Answer

If the maternal X chromosome is inactive and seen as Barr body in one cell, then it is the maternal X chromosome that is inactive and seen as a Barr body in every cell of that woman's body.

Correct AnswerverifiedShow Answer

A woman inherits a mutant BRCA1 allele from her mother. She has an increased risk of developing breast cancer because

Correct AnswerverifiedShow Answer

Specialized cells differ from one another because

Correct AnswerverifiedA

In the absence of lactose,

Correct AnswerverifiedShow Answer

A(n) ___ is to reproductive cloning as a(n) ___ is to therapeutic cloning.

Correct AnswerverifiedC

Angiogenesis contributes to carcinogenesis because

Correct AnswerverifiedShow Answer

If tumor cells have a faulty, non-functional proteinase, they will be unable to undergo which of the following processes?

Correct AnswerverifiedShow Answer

Why is it necessary to "starve" the donor cells prior to reproductive cloning?

Correct AnswerverifiedShow Answer

In the regulation of the lac operon, when lactose is present,

Correct AnswerverifiedShow Answer

Signal transduction pathways can stimulate transcription activators.

Correct AnswerverifiedShow Answer

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False

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Transcription of the genes of the lac operon is __ unless _ is _____.

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A

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A(n) _ is to reproductive cloning as a(n) _ is to therapeutic cloning.

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C

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