Final answer:
The cell theory states that all living organisms are made up of cells that are the basic units of life, and all cells come from pre-existing cells. It also emphasizes that cells contain common structures such as the plasma membrane, cytoplasm, DNA, and ribosomes.
Step-by-step explanation:
The cell theory is a fundamental scientific principle in biology that explains the properties of cells. It consists of three main components:
- All living organisms are composed of one or more cells.
- Cells are the basic units of structure and function in living organisms.
- All cells arise from pre-existing, living cells.
In addition to the core principles, cells share several basic structural components, such as:
- A plasma membrane, which serves as a barrier to contain the cytoplasm and separate the cell from its environment.
- Cytoplasm, a jelly-like substance that contains all the organelles and cellular components.
- DNA, the genetic material responsible for inheritance and guiding the cell's functions.
- Ribosomes, which are responsible for protein synthesis within the cell.
The cell theory was developed from observations by multiple scientists, including Matthias Schleiden, Theodor Schwann, and later, Rudolf Virchow, who concluded that all cells divide from existing cells, establishing the continuous chain of life.