What Is DNA?
All organisms are composed of cells. Each cell has DNA, or deoxyribonucleic acid. It is a double helix molecule, usually within the nucleus, that encodes the all of the genetic instructions for the organism.
The Structure of DNA
DNA is packaged into chromosomes for cell division. There are four things involved in eurkaryotic chromosomes: Histone proteins, chromatin, DNA and nucelosomes.
Nucleosomes are DNA is wrapped around histone proteins. Nucleosomes are then packed together in a "beads on a string arrangement" to form chromatin. Chromatin is only visible under a microscope when the cell is about to undergo cell division (during prophase). This is because the chromatin super coils and condenses, which makes it more visible.
Nucleosomes are DNA is wrapped around histone proteins. Nucleosomes are then packed together in a "beads on a string arrangement" to form chromatin. Chromatin is only visible under a microscope when the cell is about to undergo cell division (during prophase). This is because the chromatin super coils and condenses, which makes it more visible.