Observations of cancer cells in culture support the hypothesis that cancer cells __________.

• A. stop dividing when they contact neighboring cells
• B. undergo apoptosis more frequently than normal cells
• C. do not exhibit density-dependent inhibition of growth
• D. require specific growth factors to divide

Answer: (C)

Verified step by step guidance

1. Understand the concept of density-dependent inhibition: Normal cells stop dividing when they come into contact with neighboring cells due to density-dependent inhibition, which prevents overcrowding and ensures organized tissue growth.
2. Recognize the behavior of cancer cells: Cancer cells often lose the ability to exhibit density-dependent inhibition, meaning they continue dividing even when they contact neighboring cells, leading to uncontrolled growth and tumor formation.
3. Eliminate incorrect options: Cancer cells do not stop dividing when they contact neighboring cells, so the first option is incorrect. Cancer cells also do not undergo apoptosis (programmed cell death) more frequently than normal cells; in fact, they often evade apoptosis, making the second option incorrect.
4. Analyze the correct option: Cancer cells do not exhibit density-dependent inhibition of growth, which aligns with their characteristic of uncontrolled division. This is the correct answer based on observations of cancer cells in culture.
5. Consider the last option: While cancer cells may require specific growth factors to divide, this is not the defining characteristic being tested in this question. The focus is on their lack of density-dependent inhibition.