The length of DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cell. How is this DNA accommodated

Options

A. Super coiling in nucleosomes
B. DNAse digestion
C. Through elimination of repetitive DNA.
D. Deletion of non-essenatial genes

Answer

To understand how the length of DNA is accommodated within the nucleus of eukaryotic cells, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Understanding the Size of DNA and the Nucleus**:
- Eukaryotic cells contain DNA that is significantly longer than the dimensions of the nucleus. For instance, the total length of DNA in a human cell can be about 1.8 meters, while the nucleus is only a few micrometers in diameter.

2. **Role of Histones**:
- Histones are alkaline proteins that play a crucial role in packaging DNA. They act as spools around which DNA winds, forming structural units known as nucleosomes. Each nucleosome consists of a segment of DNA wrapped around a core of histone proteins.

3. **Formation of Nucleosomes**:
- The DNA wraps around histones to form nucleosomes, which are the fundamental units of chromatin. This packaging reduces the length of DNA significantly, allowing it to fit within the nucleus.

4. **Supercoiling**:
- In addition to nucleosome formation, DNA undergoes supercoiling. This is a process where the DNA helix twists upon itself, further compacting the DNA structure. Supercoiling occurs in the nucleosomes and contributes to the overall condensation of DNA.

5. **Chromatin Structure**:
- The combination of nucleosome formation and supercoiling results in a highly organized structure known as chromatin. This structure is essential for the efficient storage of DNA and plays a role in gene regulation.

6. **Mitosis and Chromosome Formation**:
- During cell division (mitosis), chromatin further condenses to form visible chromosomes. This process ensures that DNA is accurately distributed to daughter cells while maintaining its compact structure.

7. **Conclusion**:
- The accommodation of DNA within the eukaryotic nucleus is primarily achieved through the processes of nucleosome formation and supercoiling, allowing the long DNA molecules to fit into the limited space of the nucleus.

### Final Answer:
The DNA is accommodated in the nucleus through supercoiling in nucleosomes.

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