A Level Biology Practice Exam

The function of histones in the cell is to form a complex with DNA. Histones are proteins that play a critical role in the packaging of DNA into a compact, organized structure called chromatin. They are positively charged and interact with the negatively charged DNA, facilitating the wrapping of DNA around histone proteins. This interaction allows the long strands of DNA to be condensed and organized, making it possible for DNA to fit within the nucleus of a cell and to regulate gene expression properly.

Forming a complex with DNA also enables crucial processes like replication and transcription to occur effectively, as the configuration of DNA and histones can be modified to either expose or hide specific genes. This dynamic regulatory feature of histones is essential for maintaining the integrity of genetic information and for controlling access to that information in response to the developmental state of the cell or environmental signals.