Lecture 4 Notes (1/28/15)CarbohydratesInclude small sugars and long polymers of sugars4 categories based on sizeMonosaccharides: smallest sugarsDisaccharides: two monosaccharides linked by covalent bondsOligosaccharides: 3-20 monosaccharidesPolysaccharides: hundreds or thousands of monosaccharides (starch, glycogen, cellulose)Monosaccharides are joined together by condensation reactions to form di, oligo, and polysaccharidesglycosidic linkages (can be alpha or beta)PolysaccharidesCellulose- specific to plantsStarch- somewhat branched structureGlycogen- very branched structure —> large # of glucose monomersNucleic AcidsNucleotidesthe monomerscan be joined in chains or be reversibly attached to other types of cell molecules (proteins)Pentose sugar + phosphate group + nitrogenous baseNucleic Acidspolymers of nucleotidesDNARNANitrogenous basesSingle ring pyrimidines (C, T, U)Double ring purines(A, G)*Carbon 5 means the phosphate is attached to carbon #5Nucleotides are joined by covalent phosphodiester linkagesLinkages give a backbone of alternating phosphates and sugars*G—C has 3 bonds while T—A has 2 bondsDNA structureNucleotides of each chain are joined by strong covalent bondsPaired chains are associated by hydrogen bonds=complementary base pairingFunctions of DNACarries information for all structures and functionsCan reproduce itself using complementary base paring (replication)2 complete copies of DNA are madeCan copy specific segments of the information into RNA (transcription)Other functions for nucleotides ATP=energy transducer in biochemical reactionsGTP=energy source in protein synthesiscAMP=essential to the action of hormones and transmission of information in the nervous systemLipidsMonomers are hydrophobic; mostly non polar covalent bonds (C&H)Structurally varied in size and arrangement of atomsTriglycerides= glycerol + 3 fatty acidsPhospholipids= glycerol + 2 fatty acids + phosphateCarotenoids= hydrocarbon chains with a terminal ringSteroids= have 4 ring structuresMany are considered macromolecules but are not polymersFatty AcidsAre amphipathic: have opposing chemical propertiesCarbons of tail can be joined by single or double bondsClicker QuestionsCarbs can be used as carbon skeletonsLinked together by a dehydration reactionUsed as a form of energyComplementary base pairing takes place between purine and pyrimidine