Chapter 2Classes of CompoundsWaterProperties of WaterProperties of WaterSlide 6Slide 7SaltsAcids and BasesSlide 10Acid-Base ConcentrationpH: Acid-Base ConcentrationSlide 13Slide 14Acid-Base HomeostasisBuffersOrganic CompoundsSlide 18Slide 19CarbohydratesSlide 21MonosaccharidesSlide 23DisaccharidesSlide 25PolysaccharidesSlide 27LipidsTriglyceridesSlide 30Saturation of Fatty AcidsPhospholipidsSlide 33SteroidsSlide 35Other Lipids in the BodyProteinsSlide 38Slide 39Slide 40Slide 41Slide 42Slide 43Protein DenaturationEnzymesSlide 46Nucleic AcidsAdenosine Triphosphate (ATP)Slide 49Function of ATPSlide 51Part B: Chemistry Comes Alive:Inorganic compoundsWater, salts, and many acids and basesDo not contain carbonOrganic compoundsCarbohydrates, fats, proteins, and nucleic acidsContain carbon, usually large, and are covalently bonded60%–80% of the volume of living cellsMost important inorganic compound in living organisms because of its propertiesHigh heat capacity◦Absorbs and releases heat with little temperature change◦Prevents sudden changes in temperatureHigh heat of vaporization◦Evaporation requires large amounts of heat◦Useful cooling mechanismPolar solvent properties◦Dissolves and dissociates ionic substances◦Forms hydration layers around large charged molecules, e.g., proteins (colloid formation)◦Body’s major transport mediumCopyright © 2010 Pearson Education, Inc.Figure 2.12Water moleculeIons in solutionSalt crystal–++Reactivity◦A necessary part of hydrolysis and dehydration synthesis reactionsCushioning◦Protects certain organs from physical trauma, e.g., cerebrospinal fluidIonic compounds that dissociate in waterContain cations other than H+ and anions other than OH–Ions (electrolytes) conduct electrical currents in solutionIons play specialized roles in body functions (e.g., sodium, potassium, calcium, and iron) Both are electrolytes◦Acids are proton (hydrogen ion) donors (release H+ in solution)HCl  H+ + Cl–Bases are proton acceptors (take up H+ from solution)◦NaOH  Na+ + OH–OH– accepts an available proton (H+)OH– + H+  H2OBicarbonate ion (HCO3–) and ammonia (NH3) are important bases in the bodyAcid solutions contain [H+]◦As [H+] increases, acidity increases Alkaline solutions contain bases (e.g., OH–)◦As [H+] decreases (or as [OH–] increases), alkalinity increasespH = the negative logarithm of [H+] in moles per literNeutral solutions:◦Pure water is pH neutral (contains equal numbers of H+ and OH–)◦pH of pure water = pH 7: [H+] = 10 –7 M◦All neutral solutions have a pH 7Acidic solutions ◦ [H+],  pH ◦Acidic pH: 0–6.99◦pH scale is logarithmic: a pH 5 solution has 10 times more H+ than a pH 6 solutionAlkaline solutions ◦ [H+],  pH◦Alkaline (basic) pH: 7.01–14Copyright © 2010 Pearson Education, Inc.Figure 2.13Concentration(moles/liter)[OH–]10010–1410–110–1310–210–1210–310–1110–410–1010–510–910–610–810–710–710–810–610–910–510–1010–410–1110–310–1210–210–1310–1[H+] pHExamples1M Sodiumhydroxide (pH=14)Oven cleaner, lye(pH=13.5)Household ammonia(pH=10.5–11.5)NeutralHousehold bleach(pH=9.5)Egg white (pH=8)Blood (pH=7.4)Milk (pH=6.3–6.6)Black coffee (pH=5)Wine (pH=2.5–3.5)Lemon juice; gastricjuice (pH=2)1M Hydrochloricacid (pH=0)10–1410014131211109876543210pH change interferes with cell function and may damage living tissueSlight change in pH can be fatalpH is regulated by kidneys, lungs, and buffersMixture of compounds that resist pH changes Convert strong (completely dissociated) acids or bases into weak (slightly dissociated) ones◦Carbonic acid-bicarbonate systemContain carbon (except CO2 and CO, which are inorganic)Unique to living systemsInclude carbohydrates, lipids, proteins, and nucleic acidsMany are polymers—chains of similar units (monomers or building blocks)◦Synthesized by dehydration synthesis◦Broken down by hydrolysis reactionsCopyright © 2010 Pearson Education, Inc.Figure 2.14+GlucoseFructoseWater isreleasedMonomers linked by covalent bondMonomers linked by covalent bondWater isconsumedSucrose(a) Dehydration synthesisMonomers are joined by removal of OH from one monomerand removal of H from the other at the site of bond formation.+(b) HydrolysisMonomers are released by the addition of a water molecule, adding OH to one monomer and H to the other.(c) Example reactionsDehydration synthesis of sucrose and its breakdown by hydrolysisMonomer 1 Monomer 2Monomer 1 Monomer 2+Sugars and starchesContain C, H, and O [(CH20)n]Three classes◦Monosaccharides◦Disaccharides◦PolysaccharidesFunctions◦Major source of cellular fuel (e.g., glucose)◦Structural molecules (e.g., ribose sugar in RNA)Simple sugars containing three to seven C atoms(CH20)nCopyright © 2010 Pearson Education, Inc.Figure 2.15aExampleHexose sugars (the hexoses shown here are isomers)ExamplePentose sugarsGlucose FructoseGalactose Deoxyribose Ribose(a) MonosaccharidesMonomers of carbohydratesDouble sugarsToo large to pass through cell membranesCopyright © 2010 Pearson Education, Inc.Figure 2.15bPLAYPLAYAnimation: DisaccharidesExampleSucrose, maltose, and lactose(these disaccharides are isomers)Glucose Fructose Glucose Glucose GlucoseSucrose Maltose LactoseGalactose(b) DisaccharidesConsist of two linked monosaccharidesPolymers of simple sugars, e.g., starch and glycogenNot very solubleCopyright © 2010 Pearson Education, Inc.Figure 2.15cPLAYPLAYAnimation: PolysaccharidesExampleThis polysaccharide is a simplified representation of glycogen, a polysaccharide formed from glucose units.(c) PolysaccharidesLong branching chains (polymers) of linked monosaccharidesGlycogenContain C, H, O (less than in carbohydrates), and sometimes PInsoluble in waterMain types:◦Neutral fats or triglycerides◦Phospholipids◦Steroids◦EicosanoidsPLAYPLAYAnimation: FatsNeutral fats—solid fats and liquid oilsComposed of three fatty acids bonded to a glycerol moleculeMain functions◦Energy storage◦Insulation◦ProtectionCopyright © 2010 Pearson Education, Inc.Figure 2.16aGlycerol+3 fatty acid chains Triglyceride,or neutral fat3 watermolecules(a) Triglyceride formation Three fatty acid chains are bound to glycerol bydehydration synthesisSaturated fatty acids◦Single bonds between C atoms;