# Prokaryotic vs Eukaryotic Cells

> The biggest divide in biology is whether a cell keeps its DNA inside a nucleus. Prokaryotes such as bacteria are small and have no membrane-bound organelles; eukaryotes are larger and divide their work among many compartments.

Web page: https://cellnaut.com/topics/prokaryote-vs-eukaryote

![Teaching illustration: Prokaryotic vs Eukaryotic Cells](https://cellnaut.com/topic-illustrations/prokaryote-vs-eukaryote-teaching.jpg)

## Labelled parts

1. **Nucleoid**: The tangled region where the bacterial chromosome lies, with no membrane around it.
2. **Cell wall and capsule**: A tough outer layer that protects the cell and keeps its shape.
3. **Nucleus**: Keeps the chromosomes inside a double membrane studded with pores.
4. **Endoplasmic reticulum**: A network of membranes next to the nucleus that builds proteins and lipids.
5. **Mitochondrion**: A membrane-bound organelle that produces ATP; prokaryotes make ATP at their plasma membrane instead.
6. **Eukaryotic plasma membrane**: Surrounds the cell and also helps it import and export material in vesicles.

## How they differ

| Feature | Prokaryotic cell | Eukaryotic cell |
| --- | --- | --- |
| Nucleus | None; DNA sits in the nucleoid | Yes, enclosed by a double envelope |
| Membrane-bound organelles | None | Many |
| Typical size | About 1 to 10 micrometres | About 10 to 100 micrometres |
| DNA | Usually one circular chromosome, plus small plasmids | Several linear chromosomes |
| Ribosomes | Smaller | Larger |
| Division | Binary fission | Mitosis followed by cytokinesis |

**What both have in common:** Plasma membrane, Cytoplasm, Ribosomes, DNA as genetic material

## Key points

- A prokaryote's DNA floats in a region called the nucleoid, with no nuclear envelope around it.
- Eukaryotes have organelles such as mitochondria and the endoplasmic reticulum, each wrapped in membrane.
- Both kinds of cell have a plasma membrane, cytoplasm, ribosomes and DNA.

## Check yourself

**1. Where is the DNA of a bacterium kept?**

- A. In a nucleus
- B. In the nucleoid region
- C. In mitochondria
- D. Outside the cell

**Answer:** B. In the nucleoid region - Prokaryotes have no nucleus; their DNA lies in an unwrapped region called the nucleoid.

**2. Which feature do prokaryotic and eukaryotic cells both have?**

- A. Mitochondria
- B. A nuclear envelope
- C. Ribosomes
- D. An endoplasmic reticulum

**Answer:** C. Ribosomes - Every cell needs ribosomes to build proteins.

## Related lessons

- [What Is a Cell?](https://cellnaut.com/learn/what-is-a-cell)
- [Cell Size and Scale](https://cellnaut.com/learn/cell-size-and-scale)

## See it in 3D

- [Bacteria Cell](https://cellnaut.com/studio/bacteria)
- [Animal Cell](https://cellnaut.com/studio/animal)

Explanations rewritten in our own words from Biology 2e, Chapter 4: Cell Structure (OpenStax), licensed CC BY-NC-SA 4.0. https://openstax.org/books/biology-2e/pages/4-introduction