The principal components of the plasma membrane are lipids (phospholipids and cholesterol), proteins, and carbohydrates. The plasma membrane protects intracellular components from the extracellular environment. The plasma membrane mediates cellular processes by regulating the materials that enter and exit the cell.
Members of the Shudra caste, for example, are relegated to performing hard physical work regardless of their skill, intelligence, or ambition. Those born into the Brahman caste must attend university or become a member of the clergy, even though they may show no interest or aptitude toward that end.
Caste system is a closed class system in which hereditary status is the life time status. Social classes are open class system in which movement from one class to another is completely unrestricted. 9. In caste system, there is no occupational mobility, i.e. one has to follow occupation of ancestors and it cannot be changed