DNA Packaging in Cells

Overview

• DNA is tightly packed to fit into the microscopic nucleus of each cell.
• Six feet of DNA fits into the nucleus via a structured packaging process.

Steps of DNA Packaging

1. Wrapping Around Histones

• DNA wraps around special protein molecules known as histones.
• The combination of DNA and histone proteins forms a structure called a nucleosome.

2. Formation of Chromatin

• Nucleosomes are packaged into a thread called chromatin.
• Chromatin is further looped and packaged with the help of additional proteins (not shown in the animation).

Formation of Chromosomes

• DNA is ultimately packed into structures visible under a microscope called chromosomes.

Chromosomes and Cell Division

• Chromosomes are not constantly present in cells.
• Chromosomes form around the time cells divide.
  • Purpose is to separate the two copies of a cell's DNA.
• In non-dividing cells, DNA is less organized.
  • DNA remains wrapped around histones but is not coiled into chromosomes.

Conclusion

• The process of DNA packaging is crucial for fitting DNA into the cell nucleus and for ensuring DNA is organized for cell division.