nuclei in meiosis , prepared by surface-spreading spermatocytes , provide a detailed examination of the constituents of the nucleus -- euchromatin , heterochromatin , sex chromatin , nucleoli , centromeres , and dense patches that seem related to rna metabolism -- and each of these structures can be seen to change in morphology and antibody labeling during the course of meiotic prophase .
C0007610
nucleus
C0019397
heterochromatin