Prokaryotic and Eukaryotic Cells | PDF - Free Printable

The image you've uploaded is a worksheet titled "Prokaryotic and Eukaryotic Cells", focusing on the structure of bacterial (prokaryotic) cells. It uses an analogy between living spaces (efficiency apartment vs. mansion) to explain the simplicity of prokaryotic cells compared to the complexity of eukaryotic cells.

Let’s go through the questions and answers based on the content in the image, and provide a clear explanation for each:

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Model 1 – Three Types of Bacterial Cells

The diagram shows three types of bacteria:
- Coccus – spherical shape
- Bacillus – rod-shaped
- Spirillum – spiral-shaped

Each cell has labeled parts: cytoplasm, free-floating DNA, ribosomes, cell wall, cell membrane, and flagellum (in bacillus).

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Question 1: Label the diagrams in Model 1 with the correct descriptions.

✔ This question asks you to label the diagrams using the provided terms.

From the diagram, the labels are already given, but here's how they should be matched:

- Cytoplasm: The gel-like substance inside the cell where organelles are suspended.
- Free-floating DNA: The genetic material (not enclosed in a nucleus).
- Ribosomes: Small structures that make proteins.
- Cell wall: Rigid outer layer providing shape and protection.
- Cell membrane: Controls what enters and exits the cell.
- Flagellum: Whip-like structure used for movement (present in bacillus only).

> ✔ The diagram is already correctly labeled.

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Question 2: What is represented by the small dots found in each of the bacteria cells?

Answer: Ribosomes

✔ Explanation:
The small dots represent ribosomes, which are responsible for protein synthesis. In prokaryotic cells like bacteria, ribosomes are not enclosed in membranes and float freely in the cytoplasm. They read mRNA and assemble amino acids into proteins.

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Question 3: What is the name of the outermost layer that forms a boundary around the outside of each cell?

Answer: Cell Wall

✔ Explanation:
The cell wall is the rigid outer layer that gives bacterial cells their shape and protects them from mechanical damage and osmotic pressure. It is made of peptidoglycan in most bacteria. It lies outside the cell membrane and provides structural support.

> Note: The cell membrane is just inside the cell wall and regulates the movement of substances in and out of the cell.

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Question 4: How is the DNA described and what does this mean?

Answer:
It is described as free-floating since they float freely in the cytoplasm because they have no nucleus.

✔ Explanation:
In prokaryotic cells (like bacteria), there is no nucleus to house the DNA. Instead, the DNA exists as a single, circular chromosome located in a region called the nucleoid, which is not surrounded by a membrane. Because it's not enclosed, it floats freely in the cytoplasm — hence the term "free-floating DNA".

This contrasts with eukaryotic cells, where DNA is enclosed within a nuclear membrane.

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Summary of Key Concepts:

| Feature | Prokaryotic Cells (Bacteria) |
|--------|-------------------------------|
| Nucleus | ✘ Absent (no membrane-bound nucleus) |
| DNA Location | Free-floating in cytoplasm (nucleoid) |
| Organelles | No membrane-bound organelles (only ribosomes) |
| Cell Wall | Present (made of peptidoglycan) |
| Shapes | Coccus (sphere), Bacillus (rod), Spirillum (spiral) |

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Final Answer Recap:

1. Labeling: Already done in the diagram.
2. Small dots: Ribosomes
3. Outermost layer: Cell Wall
4. DNA description: Free-floating → means DNA is not enclosed in a nucleus and floats in the cytoplasm.

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This worksheet helps illustrate the simplicity of prokaryotic cells compared to eukaryotic cells, setting up a foundation for understanding cellular complexity later.