Deck 10: Eternal Life: Cell Immortalization and Tumorigenesis

Question 1

Some cancer cells escape crisis by

A)Overexpressing hTERT.
B)Activating the ALT mechanism.
C)Shortening their telomeres.
D)A and B.
E)None of the above.

Answer 1

D

Question 2

Why does loss of telomerase activity in humans lead to severe phenotypes in the first generation,while loss of telomerase activity in laboratory mice takes several generations to exhibit any sort of phenotype?

A)Mouse cells have shorter telomeres.
B)Human cells have shorter telomeres.
C)Mouse cells express higher levels of hTERT.
D)Human cells express higher levels of hTERT.
E)The length of mouse telomeres does not change over time.

Answer 2

Human cells have shorter telomeres.

Question 3

In normal cells,the telomeric DNA sequences

A)Get shorter with successive cell generations.
B)Get longer with successive cell generations.
C)Remain unchanged throughout successive cell generations.
D)Disappear after the first generation of daughter cells.
E)None of the above.

Answer 3

Get shorter with successive cell generations.

Question 4

Breakage-fusion-bridge BFB)cycles may help drive tumorigenesis by

A)Shortening telomeric DNA.
B)Driving cellular proliferation.
C)Promoting telomere instability.
D)Providing a means for cells to acquire additional mutations.
E)Increasing expression levels of hTERT.

Question 5

Human cancer cells that lack telomerase activity may

A)Be in crisis.
B)Have shorter telomeric repeat sequences.
C)Demonstrate the exchange of sequence information between telomeres through unequal crossing over.
D)Undergo chromosomal translocations.
E)All of the above.

Question 6

Which of the following is MOST likely true of aggressively dividing cancer cells?

A)They do not express telomerase.
B)They do not express hTERT.
C)They are in a state of cell crisis.
D)Their telomeres are stabilized not shortening with each cellular division).
E)None of the above.

Question 7

The structures located at the ends of chromosomes for protection and for prevention of end-to-end fusion are known as

A)Centromeres.
B)Telomeres.
C)Telocaps.
D)Shields.
E)Chromosome end clocks.

Question 8

Which of the following statements is TRUE?

A)Senescent cells can be induced to proliferate.
B)Senescent cells are viable.
C)Senescent cells are undergoing cell death.
D)Senescence is a key step in promoting neoplastic proliferation.
E)None of the above.

Question 9

Which of the following proteins is NOT part of the shelterin complex?

A)TRF1
B)TRF2
C)POT1
D)TIN2
E)None of the above

Question 10

Which of the following is NOT commonly present at high levels in senescent cells?

A)p16^INK4A
B)p21^Cip1
C)SV40 large T antigen
D)β-galactosidase enzyme
E)None of the above

Question 11

Which of the following mechanisms would NOT contribute to cancer cell transformation?

A)Erosion of telomeric DNA
B)Regeneration of telomeric DNA through the ALT mechanism
C)Repeated breakage-fusion-bridge BFB)cycles
D)Stabilization of telomeres
E)Increased expression of telomerase

Question 12

Which of the following is NOT a characteristic of aging cells?

A)Lengthening of telomeric DNA sequence
B)Increased telomere erosion
C)Accumulation of telomere-dysfunction-induced foci TIFs)
D)B and C
E)None of the above

Question 13

Which of the following is NOT a common characteristic of human senescent cells?

A)Heterochromatic foci present in the nucleus
B)Positive staining for Ki67
C)Large cytoplasm
D)"Fried egg" appearance in culture
E)None of the above