Final answer:
All cells have a cell membrane, cytoplasm, and ribosomes, which are essential for basic cellular functions such as protection, substance management, and protein synthesis.
Step-by-step explanation:
Some structures found in all cells include the cell membrane, cytoplasm, and ribosomes. All cells, whether prokaryotic or eukaryotic, have these components. The cell membrane is a protective barrier that regulates what enters and leaves the cell. The cytoplasm is a jelly-like substance that contains all the cell’s components outside the nucleus. Ribosomes are the molecular machines responsible for protein synthesis. While these are common in all cells, structures like the nucleus, chloroplasts, and mitochondria are found specifically in eukaryotic cells, not prokaryotic cells.