A gene is a piece of DNA that expresses a protein, which is a molecule that then does something in a cell, often it does a lot of different things.

Genetics is the science of genes and heredity. Heredity refers to any attribute that is passed on from parent to offspring. Most often, this refers to genetic material, that is, DNA, but there are some proteins that can be passed from parent to offspring as well that can have effects (this is called "epigenetics", and still isn't well understood, since it's very new). A gene is a piece of DNA that expresses a protein, which is a molecule that then does something in a cell, often it does a lot of different things.

Every part of your body has been created due to your own unique genes.Genes are the fundamental part of life that are passed on from one living organism to another, determining what that organism is and looks like. Your genes were given to you by your parents -- they are a combination of the genes your parents have. There is a gene that determines what color hair you have, and there's another gene that controls what color eyes you have, and so on for the rest of your body. Genes not only control your appearance, but also make sure your body is working properly, from your tiny cells to your body as a whole. Genes are made up of a very small substance called DNA (which is short for "Deoxyribonucleic acid"), but nobody knew this until the 1940s because DNA is so tiny. Your DNA is in every cell of your body, with few exceptions.

Genetics is the study of heredity -- lots of people want to know why they have the traits they do, and which relatives of theirs share these traits with them.