Question

Which of the following is the correct order of the levels of DNA packaging in eukaryotic chromosomes?

A) nucleosome → chromatin fiber → looped domains → heterochromatin
B) nucleosome → looped domains → chromatin fiber → heterochromatin
C) heterochromatin → nucleosome → chromatin fiber → looped domains
D) chromatin fiber → heterochromatin → nucleosome → looped domains
E) chromatin fiber → nucleosome → looped domains → heterochromatin

Answer 1

The correct order of DNA packaging in eukaryotic chromosomes is nucleosome, chromatin fiber, looped domains, and then heterochromatin.

Step-by-step explanation:

The correct order of the levels of DNA packaging in eukaryotic chromosomes from least complex to most complex is: DNA → nucleosome → chromatin fiber → looped domains → heterochromatin. This packaging is essential for fitting the large genome into the cell's nucleus. Initially, DNA wraps around histone proteins to form nucleosomes, resembling beads on a string. These nucleosomes are further organized into a 30 nm fiber known as a chromatin fiber, which is further coiled and packed into looped domains that make up the structure of the chromosome. During cell division, the chromatin becomes even more compacted to form heterochromatin to ensure proper segregation of chromosomes.

The most correct answer to the student's question is A) nucleosome → chromatin fiber → looped domains → heterochromatin.