BIOLOGY 151 Lecture Notes - Hydrolysis, Thymine, Polymerization
Document Summary
A nucleic acid is a polymer of nucleotide monomers. Nucleotides are each composed of a phosphate group, a sugar, and a nitrogenous base: the sugar is ribose in ribonucleotides and deoxyribose in deoxyribonucleotides. There are two groups of nitrogenous bases: purines (adenine/guanine, pyrimidines (cytosine/uracil/thymine) Uracil is found only in ribonucleotides, and thymine is found only in deoxyrionucleotides. A condensation reaction forms a phosphodiester linkage between the phosphate group on the 5" carbon of one nucleotide and the oh group on the 3" carbon another. Types of nucleotides involved: ribonucleotides which contain the sugar ribose and form rna, deoxyribonucleotides which contain the sugar deoxyribose and form dna. The sugar phosphate backbone of a nucleic acid is directional one end has an unlinked 5" carbon, and the other end has an unlinked 3" carbon. The nucleotide sequence is written in the 5"-3" direction. This reflects the sequence in which nucleotides are added to a growing molecule.