Final answer:
The chemical attraction between histone proteins and DNA in a nucleosome is due to the positively charged histone proteins binding to the negatively charged phosphodiester backbone of DNA. Chemical modifications can alter the charge and affect how tightly the DNA is wound around the histones. This interaction is important for DNA packaging and gene expression regulation in eukaryotic cells.
Step-by-step explanation:
The chemical attraction between histone proteins and DNA in a nucleosome is due to the positively charged histone proteins binding to the negatively charged phosphodiester backbone of DNA. Histones are rich in basic amino acids such as lysine and arginine, which have positively charged side chains. This allows them to bind to the negatively charged DNA.
Additionally, chemical modifications like acetyl groups can alter the charge of the histone proteins and affect how tightly the DNA is wound around the histones. Changes in the charge can open or close regions of chromatin to transcription.
This interaction between histone proteins and DNA is important for DNA packaging and gene expression regulation in eukaryotic cells.