Question

Which of the following correctly represents the basic repeating unit in prokaryotes versus eukaryotes?

Options

• Prokaryotes: nucleosome; Eukaryotes: loop domain

• Prokaryotes: supercoil; Eukaryotes: solenoid

• Prokaryotes: loop domain; Eukaryotes: nucleosome

• Both: histone octamer

Answer 1

The basic repeating unit differs between prokaryotes and eukaryotes. In prokaryotes, the loop domain (a supercoiled segment of DNA) serves as the fundamental repeating unit. In eukaryotes, the nucleosome—consisting of DNA wrapped around a histone octamer—is the basic repeating unit, with a diameter of approximately 10 nanometres and containing ~200 base pairs of DNA.