Final answer:
The regions in bacterial chromosomes responsible for compaction are known as nucleoid regions. These regions enable the storage of long DNA sequences within a small cell space, different from eukaryotic cells which use histone proteins for DNA organization.
Step-by-step explanation:
The regions of bacterial chromosomes that contribute to chromosome compaction are called nucleoid regions. In prokaryotes such as bacteria, the DNA is not organized around histone proteins like in eukaryotic cells, but instead, it is supercoiled within the centrally located nucleoid. This compaction is essential for the bacterial cell to accommodate the large chromosome within the limited space of the cell.
In comparison, eukaryotic cells have different regions within their chromosomes, such as heterochromatin and euchromatin, characterizing the types of compaction and genetic activity within a eukaryotic chromosome. While heterochromatin is tightly packaged and usually contains genes that are not expressed, euchromatin is less dense and often contains genes that are being transcribed. Both of these regions can be distinguished by staining in eukaryotic chromosomes during interphase.