From minute mosses to huge conifers, and from invisible bacteria to the huge blue whale, all organisms have a basic unit called the cell. The cell is the basic structural and functional unit of life. This chapter compares plant and animal cells, describes specialised human cells, and explains the functions of the different cell organelles.
1. Cell – The Fundamental Unit of Life
- A building wall is made up of numerous bricks; a bee hive is composed of numerous hexagonal units. In the same way, organisms are made up of cells.
- The basic functional unit of an organism is called a cell. Cells are the basic building blocks of an organism, just as atoms are the basic building blocks of matter.
- Structure of a cell is the arrangement of parts or organelles in a cell; function is the activity of each part or organelle.
- The human body is made up of animal cells and a plant is made up of plant cells.
- Cells are microscopic and can be seen only under a microscope.