Lecture 3 Notes (1/26/15)All living organisms have 4 kinds of carbon-based macromolecules-proteins-carbohydrates-lipids-nucleic acidsMost macromolecules are POLYMERS, which are long chains of smaller molecules called MONOMERS, joined by covalent bondsBuilding blocks of lifeAmino acid————proteinNucleotide————nucleic acidSugar (monosaccharides)——————polysaccharide (can be linear or branched)Phospholipid (fatty acid)———membrane (2 tiered structure)Important Functional GroupsHydroxyl——————Polar. Hydrogen bonds w/water to dissolve molecules. Enables linkage to other molecules by condensationAldehyde——————C=O group is very reactive. Important in building molecules and in energy-releasing reactionsKeto————————C=O group is important in carbs and in energy reactionsCarboxyl——————Acidic. Ionizes in living tissues to form -COO- and H+. Gives up -OH to enter into condensation reactionsAmino———————Basic. Accepts H+ in living tissues to form -NH3+. Gives up H+ to enter into condensation reactionsHow to make a polymerCondensation=Water out; energy inHow to break a polymerHydrolysis=Water in; energy outPROTEINSProteins have a great diversity of functionEnzymes-catalytic proteinsDefensive proteins-(antibodies)Hormones-control physiological processesReceptor proteins-recieve and respond to molecular signalsStructural proteins-provide physical stability and movementTransport proteins-carry substances within the organismGenetic regulatory proteins-regulate when, where and how much a gene is expresses-Polymers of 20 different amino acids-Linked by peptide bond-Vary in length from a few amino acids to thousands-Vary in composition of amino acids*Titin is a huge protein (34,000 amino acids) and adds flexibility to muscle fibers*Thrytropin releasing hormone is a very small protein (3 amino acids) and controls secretion of thyroid hormone-Amino acids are grouped according to the properties of their side chain (R) groupsSynthesis of Proteins–––––––-Grow from N-terminus —> C-terminus ; each additional amino acid joined to C-term of previous one-Fold into specific, reproducible shapes as a result of the amino acid composition and order-Some proteins made from just one polypeptide ; others made from severalLevels of Protein StructurePrimary structure (1) - the sequence of amino acidsDetermines secondary and tertiary structure (how it folds)Secondary structure (2) -Regular, repeated pattern in different regions of the amino acid chain that arise from hydrogen bonding between amino acidsAlpha helix: right-handed coil resulting from hydrogen bondingBeta pleated sheet: two or more polypeptide chain segments are aligned and held together by hydrogen bondsTertiary structure (3) - 3D shape that arises from bending and folding interactions between R groups-The outer surfaces present functional groups that can interact with other moleculesDisulfide bridges: The terminal where an SH group of cysteine can react with another cysteine side chain -Different amino acid sequence leads to a different tertiary structure, therefore a different functionQuaternary structure (4) -Association of two or more polypeptides to form the functional protein-Proteins bind noncovalently with other cellular or extracellular molecules to perform their functions-Binding is VERY specificChaperones: Proteins that help prevent inappropriate interactions Heat shock proteins (HSPs): The general class of stress-induced chaperone proteinsDenaturation: A protein that gets heated causing the secondary and tertiary structures to be broken downConditions that affect secondary and tertiary structure-High temperature-pH changes-High concentrations of polar molecules-Nonpolar substancesClicker QuestionsWhat is NOT true about the primary structure of a protein?Cannot be branchedHeld together by covalent bondsUnique to that proteinDetermines the tertiary strutter Is the sequence of amino acidsWhich of the macromolecules polymerizes to form branched