A cell is the basic, fundamental unit of life. It is the smallest structural and functional unit of an organism that can exist independently. A single cell can carry out all the processes necessary for life, such as metabolism, growth, reproduction, and response to stimuli.
Key Features of a Cell:
- Cell Membrane: This outer layer surrounds the cell and controls what enters and exits.
- Nucleus: This central organelle contains the cell's genetic material (DNA).
- Cytoplasm: The jelly-like substance that fills the cell and contains all the other organelles.
Examples of Cells:
- Red blood cells carry oxygen throughout the body.
- Nerve cells transmit signals in the nervous system.
- Muscle cells contract to produce movement.
- Bacteria are single-celled organisms.
The study of cells is called cytology**. It is a vast and complex field, with many different types of cells and specialized functions.
