A diagram shows the three separate components of a nucleotide and how they are combined to form a complete molecule. A nitrogenous base is represented as a purple hexagon. A sugar is represented as a grey pentagon. A phosphate group is represented as a light brown circle. A cut-away from the generic nitrogen base shows the chemical structure of the three types of pyrimidine bases (cytosine, thymine, and uracil) and the two types of purine bases (adenine and guanine).
Complementary base pairs: purine-pyrimidinepairs; sugar-phosphate backbone; 2 DNA strands wound around one another to produce a double helix; stabilized in part by hydrogen bonds between nitrogenous bases on either strand; due to the geometry of the bases & amount of space available in helix, H bonds only form when A and T w/ 2 bonds or G and C w/ 3 bonds line up on opposite strands
3 Main differences between DNA & RNA: RNA uses the sugar Ribose while DNA uses Deoxyribose. RNA is single stranded while DNA is double stranded. RNA uses the nitrogenous base Uracil whereas DNA uses the nitrogenous base Thymine.
"This Double Helix is a scientific model of B deoxyribonucleic acid, which is the most common form of DNA. DNA is a chemical carrier of our genes. It has an elegant geometric structure that allows it to store a massive amount of information. Every organism has its own DNA, and it is our DNA that makes each of us unique. Beads representing Phosphorus and Deoxyribose are 15 mm wide and multifaceted, and beads representing nitrogenous bases are oval and flat, 25 mmX20 mm."