Correct Option
The correct option isAll cells contain a nucleus and mitochondria.
Explanation
Cell Theory is a fundamental principle in biology that describes the properties of cells. It was originally formulated by Matthias Schleiden and Theodor Schwann in 1839 and later expanded by Rudolf Virchow in 1855. The modern version of the theory establishes the universal criteria for what constitutes life at the cellular level.
Option Analysis
- All living organisms are composed of cells. is a component: The theory states that all living organisms are composed of one or more cells and the products of cells. This was the primary postulate proposed by Schleiden and Schwann.
- The cell is the basic unit of life. is a component: The cell is defined as the basic structural and functional unit of life. All vital functions of an organism occur within cells.
- All cells arise from pre-existing cells. is a component: Rudolf Virchow added the phrase "Omnis cellula-e cellula", which translates to "all cells arise from pre-existing cells." This rejected the earlier notion of spontaneous generation.
- All cells contain a nucleus and mitochondria. is NOT a component: This statement is factually incorrect regarding the universal definition of a cell. Prokaryotic cells (such as bacteria and archaea) lack membrane-bound organelles, meaning they do not possess a defined nucleus or mitochondria. Despite lacking these structures, they are fully functional cells covered under Cell Theory.
Key Takeaway: Modern Cell Theory relies on three pillars: (1) All living things are made of cells, (2) The cell is the basic unit of life, and (3) All cells come from pre-existing cells. Specific organelles like the nucleus or mitochondria are characteristics of eukaryotic cells, not a requirement for all cells.