Describe how long strands of double-helical DNA fit into the nucleus of a single cell?
First, the double strand is usually wrapped proteins called histones to form structures called nucleosomes. These nucleosomes are often described as ‘beads on a string’ with the string being the double strand DNA. The ‘beads on a string’ structure then forms a helix by coiling in on itself. This structure is often called the ’30 nm structure’ since the diameter of the helix is 30 nm. This ’30 nm structure’ is not rigid and can become ‘wavy’ to save more space in normal chromatin. This wavy structure can further fold in on itself during mitosis to form the ultra-dense chromosome structure.
