Deck 12: Maintenance of Genomic Integrity and the Development of Cancer

Question 1

Which of the following is true of the BRCA1 gene?

A)Its product normally functions in DNA repair.
B)Germ-line mutations in this gene are associated with an increased risk for breast and ovarian cancers.
C)Somatic mutations in this gene are associated with an increased risk for ovarian cancer.
D)A,B,and C.
E)None of the above.

Answer 1

A,B,and C.

Question 2

Which of the following may result in loss of function of a tumor suppressor gene?

A)Nondisjunction of sister chromatids
B)Failure of a chromatid containing a tumor suppressor gene to attach to a spindle fiber during cell division
C)Hypermethylation of the promoter for the gene
D)A,B,and C
E)None of the above

Answer 2

A,B,and C

Question 3

Keratoses,or benign skin lesions,often exhibit

A)Mutant p53 alleles.
B)Mutations carrying a dipyrimidine substitution.
C)Mutations resulting from exposure to UV light.
D)A,B,and C.
E)None of the above.

Answer 3

A,B,and C.

Question 4

Mutations that result in compromised function of the spindle assembly checkpoint during mitosis may directly contribute to

A)Impaired p53 function.
B)Impaired DNA replication.
C)Aneuploidy.
D)A and B.
E)None of the above.

Question 5

The DNA polymerase pol-δ

A)Is involved in DNA synthesis.
B)Is involved in proofreading newly synthesized DNA.
C)Exhibits exonuclease activity.
D)A,B,and C.
E)None of the above.

Question 6

Which of the following mechanisms is involved in double-strand DNA repair?

A)Homology-dependent repair
B)Nonhomologous end joining
C)Mismatch repair
D)A and B
E)A,B,and C

Question 7

A patient with chronic myelogenous leukemia CML)exhibits chromosomal translocations in both lymphocytes and myeloid cells.This suggests that the cell in which the initiating mutation occurred was MOST likely

A)A lymphocyte.
B)A macrophage.
C)A neutrophil.
D)A hematopoietic stem cell.
E)A myeloid precursor.

Question 8

Which of the following may result in point mutations that can contribute to cancer?

A)Deamination of 5-methylcytosine
B)Unrepaired single-strand breaks during DNA synthesis
C)Microsatellite instability
D)Exposure to UV radiation
E)All of the above

Question 9

Which of the following types of cells are most protected from genomic damage?

A)Stem cells
B)Differentiated cells
C)Transit-amplifying cells
D)Dividing cells
E)A,B,and C

Question 10

The chemical structure formed from the reaction of a DNA base with a carcinogen is called

A)A lesion.
B)An adduct.
C)An ultimate carcinogen.
D)A xenobiotic.
E)None of the above.

Question 11

Defects in which of the following cellular processes may contribute to an increased incidence of cancer?

A)Nucleotide-excision repair
B)Mismatch repair
C)Base-excision repair
D)A ,B,and C
E)None of the above

Question 12

Which of the following types of mutations are advantageous to cancer cell growth?

A)Those resulting in defective mismatch repair
B)Inherited defects in double-strand DNA repair
C)A defect in nucleotide-excision repair
D)A,B,and C
E)None of the above