Study Figure 2.6 below to see how a chromosome is arranged.
1. The DNA strand coils round protein molecules called histones. The structures formed are called nucleosome.
2. Nucleosomes are packed close together into coils forming a solenoid structure or fiber.
3. The solenoid fiber is further coiled to from the chromatin fiber. How this is done is still not known. It is clear, however, that chromatin fibers become visible as a result of the coiling, packing and condensing.