Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
The cell is the basic structural, functional, and biological unit of all living organisms. Cells can be prokaryotic (without a nucleus) or eukaryotic (with a nucleus).
5 Must Know Facts For Your Next Test
Cells are the smallest units of life capable of performing all necessary life functions.
Eukaryotic cells have membrane-bound organelles, including a nucleus that contains genetic material.
Prokaryotic cells lack membrane-bound organelles and have their DNA freely floating in the cytoplasm.
The cell membrane controls the movement of substances in and out of the cell.
Cell theory states that all living things are made up of cells, and all cells come from pre-existing cells.