Here's why:
* Prokaryotic cells (bacteria and archaea) have ribosomes, the cellular machinery responsible for protein synthesis.
* Eukaryotic cells (plants, animals, fungi) also have ribosomes and carry out protein synthesis.
* Viruses are not considered "living" cells, but they still rely on the host cell's protein synthesis machinery to create viral proteins.
While cells may differ in other ways, protein synthesis is essential for the basic functions of all cells, including growth, metabolism, and reproduction.
