Which one of the following structures is NOT found in prokaryotes?

Prokaryotic cells, which include bacteria and archaea, are defined by their lack of a membrane-bound nucleus and other membrane-bound organelles [1]. Instead of a true nucleus, their genetic material is located in a region called the nucleoid, which is not enclosed by a nuclear envelope or nuclear membrane [1]. In contrast, all prokaryotic cells possess a cell membrane (plasma membrane) that encloses the cytoplasm [1]. Most prokaryotes also have a rigid cell wall for structural support [1]. Additionally, they contain ribosomes, which are essential for protein synthesis, although these are smaller and simpler than those found in eukaryotes. Therefore, while cell membranes, ribosomes, and cell walls are standard components of prokaryotic architecture, the nuclear envelope is exclusively a eukaryotic feature.

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 2: The Invisible Living World: Beyond Our Naked Eye > 2.5 Why Is Cell Considered to Be a Basic Unit of Life? > p. 24