Figure 5.8 The Nucleus, Chromatin, and Chromosomes (A) Chromatin consists of nuclear DNA and the proteins associated with it. When the cell is not dividing, the chromatin is dispersed throughout the nucleus. This two-dimensional image was made using a transmission electron microscope. (B) The nuclear envelope has many pores that regulate traffic of large molecules such as RNA and proteins in and out of the nucleus. (C) The chromatin in dividing cells becomes highly condensed, so that the individual chromosomes can be seen. This three-dimensional image of isolated metaphase chromosomes was produced using a scanning electron microscope.