DNA packaging

Definition

DNA packaging is the process by which DNA molecules are compacted into a dense, organized structure within a cell. This allows the long DNA strands to fit inside the cell nucleus and protects them from damage.

5 Must Know Facts For Your Next Test

1. Histones are proteins around which DNA winds to form nucleosomes, the fundamental units of chromatin structure.
2. Eukaryotic chromosomes consist of DNA wrapped around histones, forming a complex known as chromatin.
3. DNA packaging influences gene expression by regulating the accessibility of transcription factors to specific regions of the genome.
4. Supercoiling is another level of DNA packaging that further compacts DNA in prokaryotes and eukaryotes.
5. Epigenetic modifications such as methylation can alter DNA packaging and thus affect gene activity without changing the DNA sequence itself.

Review Questions

• What role do histones play in DNA packaging?
• How does supercoiling contribute to DNA compaction?
• Explain how epigenetic modifications can influence gene expression through changes in DNA packaging.

Related terms

Histone: Proteins that help package eukaryotic DNA into nucleosomes.

Chromatin: The complex of DNA and proteins, mainly histones, that forms chromosomes within the nucleus of eukaryotic cells.

Supercoiling: A method of compacting DNA where the double helix twists upon itself.