Deoxyribonucleic acid.

Dee-ox-ee-rye-bo-new-clay-ick-acid.

Yeah! That’s what DNA stands for.

DNA has instructions to make all the proteins that make you who you are. How do proteins determine who you are? Well, the kinds of proteins your cells make, how many of them, and when, determines your height, hair color, eye color, skin color, personality, talents, and well, everything else about you. Now, some things can change slightly based on your life experiences–such as likes and dislikes–but the basics of who you are come from DNA’s set of instructions.

DNA is shaped like a twisted ladder (also known as a double helix). Considering how much information it has, its structure is quite simple. The sides of the ladder are made of a sugar (called deoxyribose) and something called a phosphate group (4 phosphorous atoms around an oxygen atom) repeated over and over again.  Phosphate, sugar, phosphate, sugar, phosphate, sugar…  The rungs of the ladder are made up of the bases you’ve probably heard of: adenine, thymine, cytosine, and guanine. A, T, C, and G for short.

The order of the bases determines what proteins are made. So people say that DNA is a language with just 4 letters. Now, if we only had these four letters in the English language, conversations would be pretty boring.

Not many words can be expressed in English with 4 letters, but LOADS of information can be carried in DNA. A “word” in DNA’s language is a gene, a DNA sequence that has instructions for a certain protein. Genes are thousands of letters long, which is how they can have so much information with only 4 letters. Here is a really short gene if we read one side of the DNA:

This gene isn’t real, but let’s pretend it’s the genetic sequence for melanin, the protein that causes brown pigment in hair and skin.  This sequence tells the cell how to make the protein.  And when the gene is “on,” lots of the protein is produced.

The last thing to know about DNA is that the letters don’t just pair up randomly. C pairs with G, and A pairs with T. They go on a lot of double dates, of course, but C always sits next to G, and A always sits with T.