• 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 – m. RNA, t. RNA, r. RNA – m. RNA, or messenger RNA, that serve as temporary copies of the information found in DNA; – r. RNA, or ribosomal RNA, that serve as structural components of protein-making structures known as ribosomes; – t. RNA, or transfer RNA, that ferry amino acids to the ribosome to be assembled.
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)
Chargaff’s Rule • Chargaff's rules states that DNA from any cell of all organisms should have a 1: 1 ratio (base Pair Rule) of pyrimidine and purine bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine.
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