I don't understand the difference between DNA, genes and chromosomes?

In the every cell of the human body, there is a part called the nucleus - this contains all of the genetic information. In each cell nucleus there are 24 pairs of chromosomes. They come in pairs because we get one chromosome from our mums, and one from our dads. Chromosomes are made up of long coiled lengths of DNA. A gene is a section of a chromosome which codes for a specific characteristic. For example, a gene may code for blue eyes. We have two copies of each gene - one one the chromosome from mum and on dad's chromosome. DNA is short for deoxyribonucleic acid. It is a chain molecule that is made up of building blocks called DNA bases. There are four different types of DNA bases, and they come together in a particular order to create the strands of DNA. Two stands of DNA join together in a structure called a double helix- which means the stands spiral around each other. So to recap, DNA bases come together in a particular order on two connected strands to create long molecules called DNA. The DNA stands are what chromosomes are made of, and chromosomes can be broken down into sections of DNA that code for a specific feature - called genes. (I would stop in between each section to ensure the student was following my answer, I would also use a whiteboard or picture to help illustrate, and I would test them on it after to check their understanding).