Describe how long strands of double-helical DNA fit into the nucleus of a single cell?

Answer 1

A typical human genome contains 3 billion base pairs for a total extended length of over 1 meter. All that information has to be stored in the microscopic nucleus of a cell. This is done through great condensation of DNA by coiling. The following is a description of DNA condensation in eukaryotes: 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.

Answer 2

Long strands of double-helical DNA are tightly compacted and packaged into chromatin, which further condenses to form chromosomes. This compaction allows the DNA to fit inside the nucleus of a cell. The DNA wraps around histone proteins to form nucleosomes, which then coil and fold to create higher-order structures that efficiently store genetic material within the limited space of the nucleus.

Answer 3

They are microscopic! They are also very tightly wound. That's actually what our chromosomes are made of.