Organization in the prokaryotic and eukaryotic

Organization of prokaryotic DNA:

• The DNA is organized as a single chromosome in the form of a double stranded circle.
• These chromosomes are packed in the form of nucleoids, by interaction with proteins and certain cations.

Organization of eukaryotic DNA:

• The DNA is associated with various proteins to form chromatin which then gets organized into compact structures, the chromosomes.
• The DNA double helix is wrapped around the core proteins, histones - basic in nature.
• The core is composed of two molecules of histones(H2A,H2B,H3& H4)
• Each core with two turns of DNA wrapped round it into nucleosome-basic unit of chromatic.
• The length of DNA is considerably reduced by formation of 10nm fiber.
• The continuous string of nucleosome represents – beads on a string form of chromatin.
• The 10nm fiber is further coiled to produce 30 nm fiber with 6 nucleosomes in every turns.
• These 30 nm fibers are further organized into loops by anchoring the fiber at A/T rich regions namely scafloldassociated regions(SARS) to a protein scafold.