What role do telomeres and telomerase play in cancer progression? Telomeres are
ID: 95654 • Letter: W
Question
What role do telomeres and telomerase play in cancer progression?
Telomeres are needed for the chromosome fusions that often occur in cancer cells, so telomerase must be reactivated for cancer to progress.
Telomerase is usually turned off in cancer cells, allowing the cell to lose its telomeres and enter apoptosis.
Telomerase activity causes cells to avoid the process of apoptosis, so most healthy cells keep telomerase on. When telomerase is turned off, a cell can progress into a precancerous state.
Telomere shortening is a natural process that limits the number of divisions a cell can undergo, but if telomerase becomes active in a cell, then the cell can reenter a proliferative phase.
A.Telomeres are needed for the chromosome fusions that often occur in cancer cells, so telomerase must be reactivated for cancer to progress.
B.Telomerase is usually turned off in cancer cells, allowing the cell to lose its telomeres and enter apoptosis.
C.Telomerase activity causes cells to avoid the process of apoptosis, so most healthy cells keep telomerase on. When telomerase is turned off, a cell can progress into a precancerous state.
D.Telomere shortening is a natural process that limits the number of divisions a cell can undergo, but if telomerase becomes active in a cell, then the cell can reenter a proliferative phase.
Explanation / Answer
D)Telomere shortening is a natural process that limits the number of divisions a cell can undergo, but if telomerase becomes active in a cell, then the cell can reenter a proliferative phase.
DNA polymerases are unable to replicate the ends of linear DNA molecules. Therefore, the ends of eukaryotic chromosomes shorten with every round of DNA replication, unless telomerase uses its RNA component to add back telomeric DNA sequences, which it does in reproductive cells. Normally, somatic cells do not express telomerase; their telomeres progressively shorten with each cell division until vital genes are lost and the cells undergo apoptosis. Transformed cells (cancerous cells) induce the expression of the telomerase gene, thus leading to cell proliferation.
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