Question

Chemotherapy, or the use of chemical agents to destroy cancer cells, is a mainstay in the treatment of malignant tumors. Most chemotherapy agents kill cancer cells by affecting the S-phase of the cell cycle. Which of the following best explains why the S-phase is targeted by the chemotherapy agents?

A) Because the cell grows and is most active during the S-phase.
B) Because the cell divides and creates new cells during the S-phase.
C) Because the cell duplicates its DNA for its daughter cells during the S-phase.
D) Because the S-phase lasts the longest amount of time of all the cell cycle phases.

Answer 1

Chemotherapy agents target the S-phase of the cell cycle because this is when the cell duplicates its DNA for its daughter cells. Chemotherapy drugs interfere with cell division by affecting the replication of DNA. By targeting the S-phase, chemotherapy agents can inhibit the replication and division of cancer cells.

Step-by-step explanation:

The reason chemotherapy agents target the S-phase of the cell cycle is because during this phase, the cell duplicates its DNA for its daughter cells. Chemotherapy drugs interfere with cell division by affecting the replication of DNA.

For example, some drugs like cordycepin disrupt replication by incorporating into the growing DNA chain and preventing the addition of nucleotides. Other drugs like taxol block spindle fiber microtubules, preventing mitotic anaphase and telophase. By targeting the S-phase, chemotherapy agents can inhibit the replication and division of cancer cells.