Question

One difference between a cancer cell and a normal cell is
A. Cancer cells cannot function properly because they suffer from contact inhibition.
B. Cancer cells continue to divide even when they're compactly packed.
C. Cell cycle of a cancer cell is arrested at S phase.
D. Cancer cells are unable to synthesize DNA.

Answer 1

Hint: Cancer cells differ from normal cells both on a histological basis and functionally. They have abnormal proliferation properties and have proved to be very harmful.

Complete answer:
Cancer cells are cells that divide endlessly, forming solid tumors and the blood is flooded with abnormal cells. Growth and repair of the body is done by cell division. In a normal cell, the cell division halts at one point of time, but when the cell is cancerous it proliferates relentlessly. Cancer cells continue to produce copies. They spread from one part of the body to another in a process known as metastasis.
Cancer cells have distinct histological features. They tend to proliferate in an area where there isn't enough space to accommodate that many number of cells and form a tumour. They grow out of control and become invasive, adversely affecting the health. Also, cancer cells are less specialized than normal cells.
Hence the correct answer is B.

Note: Cancer cells have various different types like Carcinoma (epithelial in origin), Leukaemia (tissues responsible for producing new blood cells, commonly in the bone marrow), Lymphoma and myeloma (develop in cells of the immune system), Sarcoma (originating in connective tissue), Central nervous system (from cells of the brain and spinal cord), Mesothelioma (originating in the mesothelium)