Which of the following is not a feature of prokaryotic cells?

Options

A. Ribosomes
B. DNA
C. Cell wall
D. Endoplasmic reticulum

Explanation

To determine which of the following is not a feature of prokaryotic cells, we need to analyze each option provided:

1. **Ribosomes**: Prokaryotic cells do contain ribosomes, which are essential for protein synthesis. These ribosomes are not membrane-bound, making them a feature of prokaryotic cells.

2. **DNA**: Prokaryotic cells have DNA, which is typically found in a region called the nucleoid. Unlike eukaryotic cells, prokaryotic cells do not have a membrane-bound nucleus, but they do possess DNA.

3. **Cell Wall**: Most prokaryotic cells have a cell wall that provides structure and protection. This is a common feature among prokaryotic organisms.

4. **Endoplasmic Reticulum**: Prokaryotic cells do not have membrane-bound organelles, including the endoplasmic reticulum. This organelle is characteristic of eukaryotic cells, where it plays a role in the synthesis and transport of proteins and lipids.

Based on this analysis, the correct answer is that the **endoplasmic reticulum** is not a feature of prokaryotic cells.

### Step-by-Step Solution:
1. Identify the features of prokaryotic cells.
2. Analyze each option provided:
- Ribosomes: Present in prokaryotic cells.
- DNA: Present in prokaryotic cells.
- Cell Wall: Present in prokaryotic cells.
- Endoplasmic Reticulum: Not present in prokaryotic cells.
3. Conclude that the endoplasmic reticulum is the only option that is not a feature of prokaryotic cells.