Slide 1Slide 2Slide 3Slide 4Biomolecules  unique to living world!Structural HierarchySlide 7The Electron-Sharing ContinuumWhy Is Water Such an Efficient Solvent?Correlation of Water’s Structure and PropertiesWhat Makes a Chemical Reaction Spontaneous?Gibbs Free-Energy ChangeSlide 13Acid–Base Reactions and pHFunctional Groups: Determinants of Chemical BehaviorChapter 3Slide 17Rate of Enzyme-Catalyzed ReactionsWhat Is a Nucleic Acid?Slide 20Slide 21Slide 22Key ConceptsHow Do Carbohydrates Store Energy?© 2011 Pearson Education, Inc.•All living things are made of similar sub-components, which are evolved to have related/different functions in different life forms (Structure and Function)•All living things rely on chemical reactions to process matter and acquire energy for cellular functions. Some energy transformations are nearly universal while some are restricted to certain species (Pathways and Transformations of Energy and Matter)•DNA is the instruction code or the blue print for life; how it is used and exchanged within and among life forms is the basis of life (Information Flow, Exchange and Storage)•Organisms and their cellular components have changed over time (biodiversity) through both selection (mutations) and random evolutionary processes (Evolution)•Life is predictably interconnected - from cells within an organism to interactions between global communities (Systems)© 2011 Pearson Education, Inc.CompartmentalizationA Bacterial Cell (prokaryotic), Plant and animal cells ( Eukaryotic )© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.Substances Found in a Living cell:Organization and function of the cell:© 2011 Pearson Education, Inc.Biomolecules  unique to living world!•Proteins•Nucleic acid•Carbohydrates•Lipids© 2011 Pearson Education, Inc.Structural HierarchyKnowledge of Knowledge of the chemical the chemical structure of structure of bio moleculesbio molecules and their and their biological biological functionfunction is very is very important in important in understanding understanding biological biological processesprocesses within the cell.within the cell. ↓Plasma membrane© 2011 Pearson Education, Inc.Atomic # ? Mass #?Isotopes? Radioisotopes? (unstable Isotopes  60 Co use in medicine)Chemical bond? (unfilled en orbitals allow formation of chemical bonds)Atoms  Molecules ? ( held together by covalent bonds)Covalent bond? (atoms sharing one or more pairs of ens) Electronegativity? ( unequal sharing of bonding electrons. Why?)Compound? (two or more elements)Dipolar compound  example = Water WHY?Polar/ non polar covalent bond?Ions? Cations and Anions? Salts?Ionic bond (interaction)?H-bond? (H linked to an electronegative atom  δ+)Hydrophilic/ Hydrophobic/ Amphiphipathic molecules?Chapter 2© 2011 Pearson Education, Inc.The Electron-Sharing Continuum•The degree to which electrons are shared in chemical bonds forms a continuum, from equal sharing in nonpolar covalent bonds, to unequal sharing in polar covalent bonds, to the transfer of electrons in ionic bonds.© 2011 Pearson Education, Inc.Why Is Water Such an Efficient Solvent?•Life is based on water because water is a great solvent.•The covalent bonds in water are polar because oxygen has a greater electronegativity than hydrogen.–Oxygen has a partial negative charge. –Hydrogen has a partial positive charge.•Hydrogen bonds?  are the weak electrical attractions© 2011 Pearson Education, Inc.Correlation of Water’s Structure and Properties•Water is unique due to its small size, bent shape, highly polar covalent bonds, and overall polarity.•Water also has several remarkable properties, largely due to its ability to form hydrogen bonds. Water is: 1.Cohesive -binding between like molecules – Results in high surface tension2. Adhesive – binding between unlike molecules 3. Denser as a liquid than a solid  ice floats4. Able to absorb large amounts of energy-–High specific heat–High heat of vaporization© 2011 Pearson Education, Inc.What Makes a Chemical Reaction Spontaneous? Chemical reactions are spontaneous if they proceed on their own, without any continuous external influence such as added energy.•The spontaneity of a reaction is determined by two factors:1. The amount of potential energy–Products of spontaneous reactions have less potential energy than the reactants.2. The degree of order–Products of spontaneous reactions are less ordered than the reactants.© 2011 Pearson Education, Inc.Gibbs Free-Energy Change•The Gibbs free-energy change (ΔG) determines whether a reaction is spontaneous or requires energy.ΔG < 0 is an exergonic spontaneous reaction.ΔG > 0 is an endergonic reaction that requires energy input.ΔG = 0 is a reaction that is at equilibrium.•Difference in Potential energy between reactants and product = ΔH•When the products are less ordered than the reactants, ΔS is positiveΔG = ΔH - T ΔS© 2011 Pearson Education, Inc.Why are some reactions exothermic?  The products have lower potential energy than the reactants.Endothermic reactions must absorb heat to proceed, but exothermic reactions release heat.© 2011 Pearson Education, Inc.Acid–Base Reactions and pH •Proton [hydrogen ion (H+)] concentration is the basis of the pH scale.–pH expresses proton concentration in a solution.•The pH of pure water is 7. –Acids have a pH of less than 7.–Bases have a pH of greater than 7.•In acid–base reactions, a proton donor (acid) transfers a proton to a proton acceptor (base).© 2011 Pearson Education, Inc.Functional Groups: Determinants of Chemical Behavior•The carbon atoms in an organic molecule furnish the skeleton that gives the molecule its overall shape.–Amino and carboxyl groups: Attract or drop a proton, respectively–Carbonyl groups: Sites of reactions that link molecules into larger, more-complex compounds–Hydroxyl groups: Act as weak acids–Phosphate groups: Have two negative charges–Sulfhydryl groups: Link together via disulfide bonds•Carbon atoms give organic molecules their overall shape; __?___ atoms determine the overall chemical behavior of organic molecules.© 2011 Pearson Education, Inc.Chapter 3•Structure of amino acids•Nature of side chains•Amino acids   proteins; peptide bonds•Protein Structure•Protein folding and function•Denaturation•How do enzymes work?© 2011 Pearson Education, Inc.© 2011 Pearson Education,