Genes in a cell are located within chromosomes, which are structures inside the nucleus. The chromosomes are made up of DNA and proteins (such as histones) that organize and protect the DNA. The DNA contains genes, which are segments that code for proteins and regulate cellular functions. Genes are thus physically found on the chromosomes inside the nucleus of eukaryotic cells. The nucleus also contains other structures like the nucleolus, but genes are specifically in the chromosomal DNA structures within the nucleus.