The role of agar gel in biotechnology is to

Options

A. combine segments of DNA into bacteria
B. make enough copies of a DNA sequence for analysis
C. produce a plastic that does not conduct electricity
D. serve as a matrix for separating DNA fragments by size

Explanation

### Step-by-Step Solution:

1. **Understanding Agar Gel**: Agar gel is a substance derived from red algae, specifically from a type called Gelidium. It is commonly used in laboratories as a gel medium.

2. **Role in Biotechnology**: In biotechnology, agar gel serves a crucial role in various techniques, particularly in the separation of DNA fragments.

3. **Gel Electrophoresis**: One of the primary applications of agar gel is in gel electrophoresis. This technique involves the separation of DNA fragments based on their size.

4. **DNA Fragmentation**: Before using gel electrophoresis, DNA is cut into smaller fragments using restriction enzymes. These enzymes recognize specific sequences in the DNA and cut it at those sites.

5. **Separation Process**: When the DNA fragments are placed in wells within the agar gel and an electric current is applied, the negatively charged DNA moves towards the positive electrode.

6. **Size-Based Movement**: The agar gel acts as a matrix that allows smaller DNA fragments to move faster and further than larger fragments. As a result, the fragments are separated by size.

7. **Extraction of Gene of Interest**: This separation allows scientists to isolate specific DNA fragments, including the gene of interest, for further analysis or experimentation.

8. **Conclusion**: Therefore, the role of agar gel in biotechnology is to serve as a matrix for separating DNA fragments by size during gel electrophoresis.

### Final Answer:
The role of agar gel in biotechnology is to serve as a matrix for separating DNA fragments by size.

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