Nucleosomes are the basic units of DNA packaging in eukaryotic cells. They consist of a segment of DNA wrapped around a core of proteins called histones. This structure helps to organize and condense the long strands of DNA, making it easier for cells to manage genetic information. Each nucleosome is made up of about 147 base pairs of DNA and is connected to adjacent nucleosomes by a short stretch of linker DNA. This arrangement forms a "bead-on-a-string" structure, which further coils and folds to create higher-order chromatin structures, essential for processes like gene expression and DNA replication.