<p> Notes # _____ - DNA</p><p>DNA stands for deoxyribonucleic acid. </p><p>DNA is found in the nucleus of eukaryotic cells and the cytoplasm of prokaryotic cells. </p><p>The DNA molecule is shaped like a double-helix, which looks like a twisted ladder or spiral staircase. </p><p>DNA is made up of a phosphate-sugar backbone and pairs of nitrogen bases (nucleotides). The four nitrogen bases are:  Adenine (A)  Thymine (T)  Cytosine (C)  Guanine (G) These bases form the “steps” of the spiral staircase or “rungs” of the ladder. The nitrogen bases pair according to the following rules:  A always pairs with T  C always pairs with G</p><p>DNA contains the recipe for all the molecules you need to survive. </p><p>DNA tells the cell what type of cell to become, what products to make, when to divide, and when to die.</p><p>Each cell contains over 6 feet of DNA if it were stretched end to end. Because of this, the DNA must be very tightly coiled into “chromosomes.” This where your genes are, you get 23 chromosomes from mom’s egg, and 23 chromosomes from dad’s sperm. There are 46 chromosomes in a complete human set. The DNA/Gene/Protein Connection</p><p>DNA contains the directions for building proteins, which are made up of amino acids. The order of the bases in the DNA molecule tell the cell which amino acids to put together in order to build the protein that the cell needs. In this way, you can think of the DNA molecule like a cookbook; it contains the recipes for all the proteins and other molecules that cells need. A gene is just one of thousands of recipes in the cookbook; it contains the instructions for building a specific protein. </p>