What Three Things Make Up the Cell Theory?


Jane Flores

The cell theory is one of the fundamental concepts in biology and describes the basic unit of life. The theory was first proposed in the 17th century by Robert Hooke, Antonie van Leeuwenhoek, and Matthias Jakob Schleiden. It has since been revised and refined, but there are three main components that make up the cell theory.

The Three Components of Cell Theory

1. All living things are made up of cells

This component states that every living organism is made up of one or more cells. Cells are the building blocks of life, and they carry out all the functions necessary for an organism to survive. From bacteria to humans, all living things are composed of cells.

2. Cells are the basic unit of structure and function in living things

This component states that cells are not only the basic structural unit but also the functional unit in all living organisms. All cellular activities like metabolism, respiration, digestion, and reproduction occur within cells.

3. Cells arise from pre-existing cells through cell division

This component states that cells do not arise spontaneously but come from pre-existing cells through cell division. This means that every new cell comes from a pre-existing cell, which divides into two or more daughter cells.

The Importance of Cell Theory

The cell theory forms the foundation for modern biology and has numerous applications in medicine, biotechnology, genetics, and ecology. By understanding how cells work together to form tissues, organs, and organ systems within an organism can help us understand how diseases occur or how drugs work.


In conclusion, the cell theory explains how all living things are made up of one or more cells that serve as both structural and functional units. This concept has revolutionized biology by forming a basis for understanding the complexity of life at the cellular level. By knowing the three components of cell theory, we can appreciate the importance of cells and how they contribute to our existence.