Is it true that heterochromatin exists in interphase nuclei?

The statement that heterochromatin exists in interphase nuclei is indeed true. Heterochromatin, which is a tightly packed form of DNA, plays a crucial role in gene regulation and maintaining chromosomal integrity. During interphase, the cell is not dividing, and this is when heterochromatin can be observed in the nucleus.

Heterochromatin is generally considered to be transcriptionally inactive, meaning that the genes located within heterochromatin regions are typically not expressed. However, it does remain present during interphase and is involved in structural roles, such as maintaining the shape of chromosomes, ensuring proper segregation during cell division, and regulating gene expression by silencing certain regions.

The other options present misunderstandings of how heterochromatin behaves during the cell cycle. While heterochromatin may be more pronounced during cell division, it does not solely form during that phase nor is it absent during interphase. Instead, it exists to maintain its functions throughout the entire cell cycle, continuously participating in vital cellular processes.