There are two types of cells. Prokaryotic cells do not have a clear and easy-to-see nucleus, and do not have a membrane, or wall, around them. Eukaryotic cells have an easy-to-see nucleus where all of the cell's functions take place, and a membrane around them. The main organelles of a cell and their uses are:
- Mitochondria: produces energy for the cell
- Endoplasmic reticulum: makes proteins and carbohydrates for the cell to use
- Golgi bodies: store and package products that the cell uses
- Plastid (present in plant cells only): contains chemicals needed to photosynthesize (create energy from sunlight); in plants only.
- Nucleus: directs the actions of the cell
- Centrosomes: guides the cell in mitosis and meiosis, the processes for cell division.
- Cell biology is mostly about how cells work, and about cell division and molecular biology.
- Histology deals with techniques for looking at tissues under a microscope.
- Cytopathology is a medical discipline that deals with techniques for looking at cells under a microscope.