BIOL 110 1st Edition Lecture 12NUCLEIC ACID - Monomers: Nucleotides - Polymers: 2 basic types of nucleic acids polymers made from slightly different monomers o DNA o RNA - Function- storage and expression of the genetic info o DNA stores genetic info o RNA expresses genetic info NUCLEOTIDES - Have 3 partso Ribose Sugar- polar and uncharged  Ribose in RNA  Modified ribose in DNA – Deoxyribose o Phosphate – polar/ negatively charged o Nitrogenous base – rings with H, C, N, O  Polar by our rule of thumb  Exception due to their ring structure- actually mostly nonpolar - Adenine - Guanine - Cytosine - Thymine , Uracil in RNANUCLEIC ACID POLYMERIZATION - N, acids polymerize using sugar phosphate - H, from sugar and OH from phosphate are removed during synthesis so water is released - Forming a covalent phosphodiester bond o Alcohol + acid  ester o Alcohol from ribose sugar, acid from the phosphate o Diester because 2 alcohols - Phosphate and sugar make backbone - Bases are covalently attached to ribose sugar – phosphate - Sequence of bases along - the polymer determines info in RNA/DNA o every heritable trait is coded inthat sequence o generally written 5’ 3 , same sequence in opposite direction is totally different information SINGLE/DOUBLE STRANDED DNA- single stranded = only one covalently bonded polymer o connected by phosphodiester - Doule strand- DNA o 2 strands pair by reversible H-bonding between complementary bases base pairs ( big purine pairs with one small pyrimidine to make base pair o Purine A with pyrimidine T o Purine G with pyrimidine CLIPIDS AND MEMBRANES - Lipids are important nonpolar molecules o Triglycerides= nonpolar  3 fatty acids , carboxylic acids with long C/H 3 OH in glycerol bond to 3 fatty acids Acid + alcohol  also ester Ester bonds made by dehydration synthesis o Function : long term energy source for future use - Phospholipids – small polymers o Part polar, part nonpolar o 2 fatty acids and 1 phosphate CB  glycerol o Ester bonds again o Function: major component of biological membrane - other lipds that aren’t polymerso steroids – completely nonpolar  far rings of C and H atoms with attachments  functions: hormones, Vitamins, membrane components