Chromosomes are organize structures of DNA and proteins that are found in cells. A chromosome is a singular piece of DNA, which contains many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions. The word chromosome comes from the Greek χρῶμα (chroma, color) and σῶμα (soma, body) due to their property of being stained very strongly by some dyes.