There are many factors that determine who we are and what we look like. In this activity, you will learn about genetics and the influence that inherited characteristics have on us. You will also learn about the unique code for your genetic makeup.

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To begin, let's look at what genetics is.

 Genetics is the branch of biology that studies heredity. That is, it studies how certain traits or characteristics are passed from one generation to another.

If you look at your relatives or the families of people you know, you can probably find examples of inherited traits. Your Grandma may tell you that you look just like your dad, you have your mother's eyes, or you have hair like cousin Dylan. Some inherited traits are quite obvious, such as skin colour, eye colour, or hair colour. Other inherited characteristics are much less obvious, which is part of what makes genetics such an interesting field of study.

Genetics is also an important branch of science because it deals with biological diversity and helps us to understand how different species can adapt or change in order to survive. In all populations of living things, there is diversity or variation — differences that occur in order to help that population to thrive. You know, for example, that there is a great deal of variability among humans. Unless you have an identical twin, no other human being looks exactly like you. These variations occur in plants and animals as well, and geneticists can study these similarities and differences to learn more about how biological diversity affects the health and survival of different species and populations.

Remember that plants and animals are made of cells (humans have about 10 trillion cells) and that all cells contain a nucleus. Within the nucleus of each cell, there are chromosomes. Each chromosome consists of molecules called DNA (deoxyribonucleic acid). These molecules contains all of the information or instructions about what characteristics an organism will have.

It took many years for scientists to figure out what DNA is and how it works. Basically, the DNA of all living organisms has the same structure and is made up of the same four chemicals. However, the four chemicals can be arranged in many different ways, which allows every living organism to be slightly different from any other organism, except in the case of identical twins. Identical twins have identical DNA. The arrangement of these  four chemicals is sometimes referred to as the "genetic code." This code gives instructions to the cells to create the organism according to the information provided by the DNA.

A lot of DNA is needed to carry all of the information about an organism's features, so DNA is arranged in strands or packages of chromosomes. Different genes are sections or segments of DNA located at particular places on the chromosomes; genes determine specific characteristics of different organisms.

Humans have 46 chromosomes arranged in 23 pairs. One copy of each chromosome comes from each parent. In the next activity, you will learn more about how your traits are inherited from your parents.