All cells have the following structures:
- DNA
- Ribosomes
- Cell Membrane
- Cytoplasm
- Cytoskeleton
Note: While ribosomes and cytoskeleton are not as obvious in prokaryotic cells (which lack a nucleus and membrane-bound organelles), they are indeed present in all cells. The others listed (cell wall and mitochondria, for example) are not found in all cells, as not all cells have a cell wall (e.g., animal cells) or mitochondria (e.g., some anaerobic organisms).