- 1). Separate the chenille stems into their different colors. Let one color represent the phosphate backbones, another represent the sugar molecules, a third represent adenine, a fourth represent thymine, a fifth represent guanine and a sixth color represent cytosine. The adenine, thymine, guanine and cytosine are called nitrogen bases, and they will be connected in base pairs to form rungs of the double helical ladder. The phosphate and sugar groups will be the two sides of the double helix.
- 2). Connect two sets of three stems together by twisting the ends together to represent the phosphate and sugar groups. Take the ends of the chenille stems and form hooks with the last half inch, hook them through each other and twist them around each other three or four times. Keep the two strands straight and laying down for now.
- 3). Cut the four sets of colored base stems into four-inch lengths with the tin snips. These will represent the nitrogen bases adenine, thymine, guanine and cytosine, which will be paired together to form sequences.
- 4). Connect bases at random along one of the nucleotides by twisting about a centimeter of the base around the nucleotide. Space them about an inch apart. In an actual DNA molecule, the base pair is connected to a sugar molecule and a phosphate molecule to form a nucleotide.
- 5). Connect the corresponding base to the free end of the previously connected bases by twisting the ends together. Connect the adenine bases to thymine bases, and the guanine bases to cytosine bases. Then, twist the free ends of the base pairs to the second phosphate strand. In a single human gene, there are between 20,000 and one million base pairs, with the pattern of base pairs acting like letters in the alphabet to spell out a recipe.
- 6). Twist the ladder shape slightly so that it forms a double helix to complete the DNA model. Each cell in our bodies contains approximately one meter's worth of DNA, with each phosphate being located 10 angstroms from the center of the helix at a pitch of 34 angstroms.
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