Chemotherapy, or the use of chemical agents to destroy cancer cells, is a mainstay in the treatment of malignant tumors. An understanding of the normal cell cycle and the behavior of malignant or cancerous cells can help one better understand how chemotherapy works to destroy cancer cells.Most chemotherapy agents kill cancer cells by affecting the S-phase of the cell cycle. Based on your knowledge of the cell cycle, which of the following best explains why the S-phase is targeted by chemotherapy agents? Because the S-phase lasts the longest amount of time of all the cell cycle phases Because the cell divides and creates new cells during the S-phase Because the cell grows and is most active during the S-phase Because the cell duplicates its DNA for its daughter cells during the S-phase

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Chemotherapy, or the use of chemical agents to destroy cancer cells, is a mainstay in the treatment of malignant tumors. An understanding of the normal cell cycle and the behavior of malignant or cancerous cells can help one better understand how chemotherapy works to destroy cancer cells.Most chemotherapy agents kill cancer cells by affecting the S-phase of the cell cycle. Based on your knowledge of the cell cycle, which of the following best explains why the S-phase is targeted by chemotherapy agents? Because the S-phase lasts the longest amount of time of all the cell cycle phases Because the cell divides and creates new cells during the S-phase Because the cell grows and is most active during the S-phase Because the cell duplicates its DNA for its daughter cells during the S-phase

Answer 1

To understand why chemotherapy targets the S-phase of the cell cycle, we need to review what occurs during each phase of the cell cycle. The cell cycle consists of several phases, including G1 (first gap), S (synthesis), G2 (second gap), and M (mitosis). During the S-phase, the cell synthesizes a complete copy of the DNA in its nucleus. This is a crucial step before a cell can divide during mitosis because each new cell needs to have an identical copy of DNA.Let's evaluate each option:Option A suggests that the S-phase is targeted because it lasts the longest. However, the duration of the S-phase is not the primary reason for targeting it; the critical events that occur during this phase are what make it a target for chemotherapy.Option B states that the cell divides and creates new cells during the S-phase. This is not accurate; cell division actually occurs during the M phase, not the S-phase.Option C indicates that the cell grows and is most active during the S-phase. While the cell is active during the S-phase, as it is duplicating its DNA, this is not the primary reason it is targeted by chemotherapy.Option D explains that the cell duplicates its DNA for its daughter cells during the S-phase. This is the correct reason why chemotherapy targets the S-phase. By interfering with DNA synthesis, chemotherapy drugs can prevent cancer cells from replicating and thereby inhibit tumor growth.

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