LifeSciTRC.org - Cells alive! - Bacterial Cell Worksheet - Free Printable

The image provided is a worksheet for labeling the structures of bacterial cells, specifically focusing on Gram-negative and Gram-positive bacteria. Below is the solution with explanations for each labeled part:

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Key to Labeling:

1. Flagellum
- Function: Helps in movement of the bacterium.
- Location: Long, whip-like structures extending from the cell surface.

2. Pilus (Fimbriae)
- Function: Used for attachment to surfaces or other cells.
- Location: Short, hair-like structures on the cell surface.

3. Outer Membrane
- Function: Provides an additional barrier in Gram-negative bacteria.
- Location: Outermost layer in Gram-negative bacteria.

4. Peptidoglycan Layer
- Function: Provides structural support and protection.
- Location: In both Gram-positive and Gram-negative bacteria, but thicker in Gram-positive bacteria.

5. Periplasmic Space
- Function: Contains enzymes that help in nutrient uptake and detoxification.
- Location: The space between the outer membrane and the inner membrane in Gram-negative bacteria.

6. Inner Membrane (Cytoplasmic Membrane)
- Function: Regulates transport of substances into and out of the cell.
- Location: Inner boundary of the cell in both Gram-positive and Gram-negative bacteria.

7. Ribosomes
- Function: Sites of protein synthesis.
- Location: Freely distributed in the cytoplasm.

8. Plasmid
- Function: Circular DNA molecules carrying additional genetic information.
- Location: Small, circular DNA molecules in the cytoplasm.

9. Nucleoid
- Function: Region containing the bacterial chromosome (genetic material).
- Location: Central region of the cell, not enclosed by a nuclear membrane.

10. Cytoplasm
- Function: Gel-like substance where cellular processes occur.
- Location: Fills the interior of the cell.

11. Capsule
- Function: Protects the cell from desiccation and phagocytosis.
- Location: Surrounds the cell wall in some bacteria.

12. Cell Wall
- Function: Maintains cell shape and protects against osmotic lysis.
- Location: Outside the cytoplasmic membrane.

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Explanation of Differences Between Gram-Negative and Gram-Positive Bacteria:

- Gram-Negative Bacteria:
- Have a thin peptidoglycan layer.
- Possess an outer membrane with lipopolysaccharides (LPS), which makes them resistant to certain antibiotics.
- Contain a periplasmic space between the inner and outer membranes.

- Gram-Positive Bacteria:
- Have a thick peptidoglycan layer.
- Lack an outer membrane.
- Are more susceptible to certain antibiotics due to the absence of an outer membrane.

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Final Answer:

Here is the completed worksheet with labels:

1. Flagellum
2. Pilus (Fimbriae)
3. Outer Membrane
4. Peptidoglycan Layer
5. Periplasmic Space
6. Inner Membrane (Cytoplasmic Membrane)
7. Ribosomes
8. Plasmid
9. Nucleoid
10. Cytoplasm
11. Capsule
12. Cell Wall

Boxed Final Answer:
\boxed{
\begin{array}{ll}
1. & \text{Flagellum} \\
2. & \text{Pilus (Fimbriae)} \\
3. & \text{Outer Membrane} \\
4. & \text{Peptidoglycan Layer} \\
5. & \text{Periplasmic Space} \\
6. & \text{Inner Membrane (Cytoplasmic Membrane)} \\
7. & \text{Ribosomes} \\
8. & \text{Plasmid} \\
9. & \text{Nucleoid} \\
10. & \text{Cytoplasm} \\
11. & \text{Capsule} \\
12. & \text{Cell Wall} \\
\end{array}
}