Which cellular structure is found in all eukaryotic cells but not in prokaryotic cells?

• A. Cell membrane
• B. Ribosomes
• C. Cytoplasm
• D. Nucleus

Answer: (D)

Verified step by step guidance

1. Understand the basic differences between eukaryotic and prokaryotic cells. Eukaryotic cells have a defined nucleus, while prokaryotic cells do not.
2. Identify the cellular structures listed in the problem: cell membrane, ribosomes, cytoplasm, and nucleus.
3. Recognize that the cell membrane, ribosomes, and cytoplasm are found in both eukaryotic and prokaryotic cells.
4. Recall that the nucleus is a membrane-bound organelle that houses the cell's genetic material and is a defining feature of eukaryotic cells.
5. Conclude that the nucleus is the cellular structure found in all eukaryotic cells but not in prokaryotic cells.