Both chromosomes and genes are made up of DNA, which is a physical molecule. DNA is one of the most common components of chromosomes. Chromosomes, which are made up of DNA and a few proteins, are larger, often microscopically visible structures in cells. Genes are much smaller DNA-based pieces of chromosomes that code for the production of proteins or RNA required by the cell. Genes are DNA segments that contain the instructions for making a particular protein that works in one or more types of cells in the body. Chromosomes are cellular structures that house a person's genes. Chromosomes, which are found in the cell nucleus, contain genes. (Hope this helps)