DNA: _____________________________ ____________ Discovered by James D. Watson and Francis Crick in _______ (with the help of Rosalind Franklin’s X-­‐ray image). Made up of repeating subunits: _______________________ (monomers) Is located in the _________________ of the cell (for eukaryotes) and the __________________ (for prokaryotes) Structure of a nucleotide: Most nucleotides “travel” as ________________________. The loss of the 2 ____________________ _______________ provides energy to form the nucleic acid (the biomolecule). Any guess what this molecule is? The lone phosphate group now connects to the sugar of another nucleotide and creates the linkage: Sugar – Phosphate – Sugar – Phosphate …etc. This linkage is often referred to as the “Sugar – Phosphate _________________________” This results in a: What distinguishes the nucleotides are the ______ different bases: A T C G Adenine and Guanine are __________________ : 2 “rings” Thymine and Cytosine are ________________________: 1 “ring” Adenine only pairs with _________________ Guanine only pairs with _________________ Therefore, there is the same amount of ______ and _______ ______ and _______ in a DNA molecule DNA is a ________________ ______________ : similar to a “twisted ladder” The side bars = ____________________________________________ (anti-­‐parallel to each other) The rungs = __________________________ Each side is said to be ____________________________ to each other. If you have one side, side, you know what the other side will be. Essentially, one side is the _________________ for the other. Due to the different shape and charges of the base, they make a different number of _____________________ ______________. G C ____ hydrogen bonds A T ____ hydrogen bonds Notice: a purine (A and G) binds to a pyrimidine (T and C) so the “rungs” are always the same ____________!