Nucleic Acids
Made from long strands of nucleotides (monomers) Nucleic acids are large biomolecules (polymers) – essential for all known forms of life Include DNA and RNA Made from long strands of nucleotides (monomers) A nucleotide contains a 5-carbon sugar, a phosphate group, and a nitrogenous base The nitrogeneous bases are connected by the sugar and the phosphate group (rungs of the ladder)
DNA vs. RNA If the sugar molecule is Deoxyribose, the nucleic acid is DNA If the sugar molecule is Ribose, the nucleic acid is RNA RNA – mRNA, tRNA, rRNA
Purines vs Pyrimidines Purines have a 2-Carbon nitrogen ring base Adenine Guanine Pyrimidines have a 1-carbon nitrogen ring base Thymine Cytosine
Nitrogeneous Bases Adenine Thymine (DNA only) Cytosine Guanine Uracil (RNA only)
Base Pairing The rules of base pairing (or nucleotide pairing) are: A with T: the purine adenine (A) always pairs with the pyrimidine thymine (T) C with G: the pyrimidine cytosine (C) always pairs with the purine guanine (G) The bases are paired with hydrogen bonds – 2 between A and T and 3 between C and G