Question

Using salts to remove specific chromatin proteins disrupts the highly compact structures of metaphase chromosomes. A scaffold composed of ______ proteins remains after salt treatment, providing anchoring sites for elongated loops of DNA.

Answer 1

Salt treatment of chromatin removes most proteins, leaving a non-histone protein scaffold, including proteins like topoisomerase, which supports the condensed chromosomes during metaphase.

Step-by-step explanation:

After treating chromatin with salts, which removes most proteins, a scaffold comprised of non-histone proteins is what remains, providing anchoring sites for DNA. This scaffolding largely consists of proteins such as topoisomerase. During the metaphase of cell division, chromosomes become highly condensed and are made up of tightly packed DNA and proteins. Initially, DNA wraps around histone proteins, forming nucleosomes, often described as 'beads on a string.' However, a higher salt concentration leads to the histones being dissociated, leaving behind the non-histone protein scaffold. This protein scaffold serves as the structural support for the condensed chromatin, ensuring the integrity of the chromosomes during metaphase.