TABLE OF CONTENTS A cell is the basic unit of life, the unit of structure and function for all organisms. Part 3 discusses the various aspects of the cell. There are three chapters in this part. In the first chapter we shall discuss the cell and its organization at different levels. We shall study the structure and function of the cell and its various organelles, organization of cell into tissues, and tissues into organs. We further discuss various organs and organ systems and how these organ systems are coordinated to make up a functional organism. A group of organisms forms a population, which is affected by a number of genetical and environmental factors. It is also discussed how various other factors such as adaptation and natural selection contribute to the evolution of population and biodiversity. The last part of the chapter is for discussing the interaction of organisms among themselves and with the ecosystem and how this can affect environmental and climatic conditions, and finally the biosphere.
The second chapter basically discusses various activities of cells. How cells multiply, cell division and cell cycles, how cells communicate with their environment and with other neighboring cells, cell-cell interaction, etc. Various physiological activities of cells such as their role in the movements, nutrition, internal transport, gaseous exchange, defense mechanisms, etc., are also discussed in detail. The last part of the chapter is mainly...
