Lecture 4 Notes 1 28 15 Carbohydrates Include small sugars and long polymers of sugars 4 categories based on size Monosaccharides smallest sugars Disaccharides two monosaccharides linked by covalent bonds Oligosaccharides 3 20 monosaccharides Polysaccharides hundreds or thousands of monosaccharides starch glycogen cellulose Monosaccharides are joined together by condensation reactions to form di oligo and polysaccharides glycosidic linkages can be alpha or beta Polysaccharides Cellulose specific to plants Starch somewhat branched structure Glycogen very branched structure large of glucose monomers Nucleic Acids Nucleotides the monomers can be joined in chains or be reversibly attached to other types of cell molecules proteins Pentose sugar phosphate group nitrogenous base Nucleic Acids polymers of nucleotides DNA RNA Nitrogenous bases Single ring pyrimidines C T U Double ring purines A G Carbon 5 means the phosphate is attached to carbon 5 Nucleotides are joined by covalent phosphodiester linkages Linkages give a backbone of alternating phosphates and sugars G C has 3 bonds while T A has 2 bonds DNA structure Nucleotides of each chain are joined by strong covalent bonds Paired chains are associated by hydrogen bonds complementary base pairing Functions of DNA Carries information for all structures and functions Can reproduce itself using complementary base paring replication 2 complete copies of DNA are made Can copy specific segments of the information into RNA transcription Other functions for nucleotides ATP energy transducer in biochemical reactions GTP energy source in protein synthesis cAMP essential to the action of hormones and transmission of information in the nervous system Lipids Monomers are hydrophobic mostly non polar covalent bonds C H Structurally varied in size and arrangement of atoms Triglycerides glycerol 3 fatty acids Phospholipids glycerol 2 fatty acids phosphate Carotenoids hydrocarbon chains with a terminal ring Steroids have 4 ring structures Many are considered macromolecules but are not polymers Fatty Acids Are amphipathic have opposing chemical properties Carbons of tail can be joined by single or double bonds Clicker Questions Carbs can be used as carbon skeletons Linked together by a dehydration reaction Used as a form of energy Complementary base pairing takes place between purine and pyrimidine bases