Eukaryotes vs Prokaryotes
Two Main Types of Cells: Eukaryotes and Prokaryotes
There are two main types of cells you need to know about: Eukaryotes and Prokaryotes.
Eukaryotic Cells
Examples of eukaryotic cells include animal cells (on the left) and plant cells (on the right). These cells are more complex and have several important features.
Key Features of Eukaryotes:
- Membrane-bound organelles (e.g., mitochondria, chloroplasts in plants)
- DNA enclosed in a nucleus
- Generally larger than prokaryotic cells
Prokaryotic Cells
Prokaryotes are simpler cells. The most common example is a bacteria cell.
Key Features of Prokaryotes:
- Cell membrane – Controls what enters and leaves the cell
- Cell wall – Provides support and protection
- Cytoplasm – Where chemical reactions happen
- Ribosomes – Where protein synthesis occurs
- Flagella – Helps the bacteria move
- DNA – Controls the cell’s activities, but not enclosed in a nucleus
- Plasmids – Small rings of DNA that can provide advantages like antibiotic resistance
Important Differences Between Eukaryotes and Prokaryotes
Eukaryotes and prokaryotes share some similarities, but they also have key differences. Here’s a helpful comparison:
| Feature | Prokaryotes (Bacteria Cells) | Eukaryotes (Animal and Plant Cells) |
|---|---|---|
| DNA | DNA is not enclosed in a nucleus; also found in plasmids | DNA is enclosed within a nucleus; no plasmids |
| Cell Membrane | Yes | Yes |
| Cell Wall | Yes | Yes (in plant cells) |
| Cytoplasm | Yes | Yes |
| Ribosomes | Yes | Yes |
| Mitochondria | No | Yes |
| Chloroplasts | No | Yes (in plant cells) |
| Permanent Vacuole | No | Yes (in plant cells) |
| Flagella | Sometimes | No |
Key Takeaways
- Eukaryotes are more complex and generally larger than prokaryotes.
- Eukaryotes make up multicellular organisms (e.g., humans and plants), while prokaryotes are typically unicellular (e.g., bacteria).
- The word “prokaryote” comes from “pro,” meaning “before,” and “karyote,” meaning “nut,” referring to cells that lack a nucleus.
- Eukaryotic cells are often part of larger, multicellular organisms, while prokaryotic cells are simple and mostly single-celled.
Fun Fact!
Eukaryotes are usually more complex because they have membrane-bound organelles like mitochondria, chloroplasts, and a nucleus. These structures help cells carry out more specialized tasks!
Questions
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Which type of cell has a nucleus?
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Name one organism that is eukaryotic.
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What is a plasmid?
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Which type of cell is generally smaller?
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Where is DNA found in a prokaryotic cell?
Summary
· Eukaryotic cells have a nucleus and membrane-bound organelles.
· Prokaryotic cells are smaller, with DNA free in the cytoplasm.
· Bacteria are prokaryotes; animals and plants are eukaryotes.
· Plasmids are found only in prokaryotic cells.
· Electron microscopes are used to view tiny prokaryotes in more detail.