What is the role of a chromosome in a cell?

According to my notes............
Chromosomes contain the genetic coding necessary for all cellular functions. Chromosomes can be seen visually through a light microscope during late interphase as well as during mitosis. The human somatic cell contains 22 somatic pairs of chromosomes responsible for organism function and a 23rd pair that differentiates gender as well as gamete formation for reproduction, the XY or XX chromosomes. Two types readily exist in prokaryotic cells: euchromatin, which are parts of chromosomes that can be readily transcribed by the cell; and heterochromatin, which is tightly wound and is not accessible to the cell for transcription. Cell differentiation into euchromatin and heterochromatin occurs in development from a germinal cell (prior to embryo differentiation) and is tissue specific in all mutlicellular prokaryotes.

I hope this helps! :)