Which type of cells enclose their DNA in nuclei and contain membrane-bound organelles?

• A. Eukaryotes
• B. Prokaryotes
• C. Bacteria
• D. Archaea

Answer: (A)

Cells that enclose their DNA in a nucleus and contain membrane-bound organelles are eukaryotic cells. In these cells, DNA sits inside a nucleus bounded by a nuclear envelope, keeping it separate from the rest of the cell. They also have various membrane-bound compartments, like mitochondria for energy, the endoplasmic reticulum and Golgi apparatus for processing and shipping proteins, and lysosomes for digestion. This level of internal organization supports more complex functions and larger cell sizes.

Prokaryotic cells, in contrast, do not have a true nucleus and lack membrane-bound organelles. Their DNA is in a nucleoid region that isn’t enclosed by a membrane. The groups listed as choices—bacteria and archaea—are prokaryotes, so they do not fit the description. Therefore, the type described is eukaryotic cells.