DNA DNA (deoxyribonucleic acid) is made of a 5 – carbon sugar (ribose), a nucleotide (ACTG), and a phosphate group (PO4).

Nucleic Acids Nucleic acids carry the genetic information in genes that is necessary to assemble all of the macromolecules of the body.  There are 2 types of nucleic acids: deoxyribonucleic acid (DNA- ATCG) and ribonucleic acid (RNA-AUCG).

Classes of Nucleic Acids Pyrimidines 6 member ring of carbon and nitrogen Cytosine (C), Thymine (T), & Uracil (U) T - only in DNA, U - only in RNA, & C - both DNA & RNA RNA DNA

Classes of Nucleic Acids Purines Are larger with a 6 member ring of carbon and nitrogen fused to a 5 member ring Adenine (A), and Guanine (G) A & G are found in both DNA & RNA

DNA Structure “Sugar – phosphate backbone” A phosphate is attached to the 5' carbon of the pentose ring Are linked by phosphodiester linkage (via dehydration synthesis) between the 3' C (OH) & the 5'C (PO4)of the next nucleotide the sugar-phosphate backbone is on the outside and the nucleotide groups are on the inside results in a repeating sugar - phosphate backbone DNA - double stranded a-double helix (RNA - single stranded) The 2 strands in DNA are antiparallel Moving in opposite directions

Chargaff’s Rule 1947 – Erwin Chargaff demonstrated that although different organisms had differing amounts of DNA, the ration of the 4 nucleotides remained constant. Human DNA showed the following: A - 30.3% T - 30.3% G - 19.5% C - 19.9% The similarity of A/T & C/G became known as Chargaff's rule. Complimentary Base Pairing C pairs with G A pairs with T or U 5'-A C T G G -3' 3'-T G A C^C -5'