Question

Which of the following represents a higher-order structure found in chromatin?

1) DNA double helix
2) 30-nm fiber
3) histone octamer
4) extended chain of nucleosomes
5) nucleosome

Answer 1

Option 2, the 30-nm fiber, represents a higher-order structure in chromatin, forming through the compaction of nucleosomes and being more complex than the DNA double helix or individual nucleosomes.Option 2 is correct.

Step-by-step explanation:

The structure that represents a higher-order structure found in chromatin is Option 2: the 30-nm fiber. This is because the chromatin structure becomes more complex as it transitions from the DNA double helix, to the formation of nucleosomes wrapped around histone proteins, to the coiling into the 30-nm fiber.

During the metaphase stage of mitosis, chromosomes are their most compact at approximately 700 nm in width, much more tightly packed than the 30-nm fibers.

When placing the structures in order from least to most complex, the correct sequence is DNA, nucleosome, chromatin, and chromosome,