Which of the following best describes a key difference between cancer cells and noncancerous (normal) cells?

• A. Cancer cells require more oxygen than normal cells to survive.
• B. Cancer cells have fewer chromosomes than normal cells.
• C. Cancer cells can divide uncontrollably and ignore normal regulatory signals.
• D. Cancer cells are unable to undergo mitosis.

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by understanding the key characteristics of normal cells. Normal cells follow strict regulatory signals that control their growth, division, and death. These signals ensure that cells divide only when necessary and stop dividing when they are damaged or no longer needed.
2. Step 2: Compare this behavior to cancer cells. Cancer cells are characterized by their ability to divide uncontrollably. They often ignore regulatory signals that would normally prevent excessive cell division or trigger apoptosis (programmed cell death).
3. Step 3: Evaluate the options provided in the question. For example, the statement 'Cancer cells require more oxygen than normal cells to survive' is not universally true, as cancer cells can adapt to low oxygen environments (hypoxia). Similarly, 'Cancer cells have fewer chromosomes than normal cells' is incorrect because cancer cells often have abnormal numbers of chromosomes, but not necessarily fewer.
4. Step 4: Consider the statement 'Cancer cells can divide uncontrollably and ignore normal regulatory signals.' This aligns with the hallmark behavior of cancer cells, as they bypass the normal checks and balances of the cell cycle.
5. Step 5: Eliminate the incorrect option 'Cancer cells are unable to undergo mitosis.' Cancer cells do undergo mitosis, but they do so uncontrollably, which is a key difference from normal cells. Thus, the correct answer is the statement about uncontrolled division and ignoring regulatory signals.