How is a cancerous cell different from a normal cell?
Normal cells exhibit contact inhibition, a property by which contact with other cells inhibits their uncontrolled growth. Cancer cells have lost this property and continue to divide without regulation, giving rise to masses of cells called tumors.
In normal cells, cell growth and differentiation is highly controlled and regulated. In cancer cells, there is a breakdown of these regulatory mechanisms. Malignant cancer cells grow very rapidly, invading and damaging the surrounding normal tissues.
Additionally, cancer cells starve the normal cells by competing for vital nutrients. They also exhibit metastasis – a property where cells sloughed from tumors reach distant sites through blood and start new tumors there.
Explanation
This answer addresses the key differences between normal and cancerous cells as stated in NCERT Chapter 8 (Human Health and Disease). The main points are: (1) Loss of contact inhibition in cancer cells, (2) Breakdown of regulatory mechanisms controlling cell growth, (3) Rapid uncontrolled division forming tumors, (4) Invasion and damage to surrounding tissues, (5) Competition for nutrients starving normal cells, and (6) Metastasis - the ability to spread to distant sites. These points cover all major differences mentioned in the textbook context.
Solution Steps
Step 1: Identify the property of contact inhibition present in normal cells but lost in cancer cells
Step 2: Explain the breakdown of regulatory mechanisms in cancer cells leading to uncontrolled division
Step 3: Describe additional properties of cancer cells - rapid growth, invasion, nutrient competition, and metastasis