Nucleus – Structure and Function Practice Test

Chromatin exists in two distinct forms inside the nucleus: heterochromatin and euchromatin. Heterochromatin is highly condensed and generally transcriptionally inactive, keeping certain regions of DNA tightly packed and less accessible. Euchromatin is less condensed, more open, and associated with active gene transcription because the DNA is more accessible to transcriptional machinery. These two states reflect how DNA packaging regulates gene expression, influenced by histone modifications and DNA methylation. Other items mentioned aren’t forms of chromatin: mitochondrial DNA and the nuclear lamina are separate nuclear components, while RNA, proteins, or cytoplasmic granules are not the chromatin forms within the nucleus.