Characteristics of LifeEnergy (Acquire and use)CellsInformation (Genetic)Replicate itselfEvolutionALL Organisms are made of cellsBacteria are the smallest200nm wideCells are:Highly organizedBounded by plasma membraneContain chemicals in aq solutionMost can divide themselvesScientists ask questions:About organismsThat can be testedBy observation/measurementsWhy are giraffes’ necks so long?Food competition?Sexual competition?Perform experiments to test this hypothesis!!!Null Hypothesis-Specifies what should be observed when the hypothesis being tested isn’t correctIn an experiment…Include control groupsKeep conditions constantRepeat the test more than onceOnly switch one condition that can be tested4 Main Atoms account for 96% of matter in organismsCarbonHydrogenNitrogenOxygenStructure fits FUNCTIONAtomic structure:Protons (+1 Charge)Never changes in an elementNeutronsCan vary=ISOTOPES!Different masses, same elementCan be radioactive & decay over timeElectrons (-1)Dalton – unit of mass for pro/neu/electrons6 protons/6 neutrons= 12 daltonsCovalent bonds- shared electronsGlue atoms togetherElectronegativity:How bad elements want their electronsVaries due to:Number of protons in the nucleusDistance between nucleus and valance shellCauses polar/nonpolar bonds!O>N>C=HIonic bonds- transferred electronsCation- + charged ionAnion- - charged ionMolecule ModelsMolecular FormulaStructural FormulaBall-and-stick ModelSpace-filling ModelWATER IS LIFEIt is a great solvent- dissolves substancesOxygen is partially -, Hydrogen partially +Molecule is bent, which sticks out the oxygen atomHydrophilic- water lovingIons and polar molecules stay in solution b/c water’s partial chargesH bonding makes it possible for charged/polar molecules to dissolveHydrophobic- water fearingUncharged and nonpolar molecules hate waterDo not interact or dissolveWater properties:Cohesion- sticks itselfAdhesion- sticks to other moleculesSurface tension- great strength of bonds on top of the surfaceDenser as a liquid than a solidHigh capacity of absorbing energy (specific heat)Acid/base reactions:Acids donate protons and increase hydronium (H30+) concentrationBases receive protons and decrease hydronium concentrationMole- unit of molecules in a certain mass6.022x10^23 molecules in 1 molMolarity- moles per literpH information:pH= -log[H+} or [H+]= 10^pH>7 =base<7 =acidbuffers minimize damage against ph changesTwo places where early reactions could’ve happened:The atmosphereDeep-sea hydrothermal ventsChemical Reactions:Reactants start itProducts are formedProceed until an equilibrium is reachedEndothermic (absorbs heat during reaction)Exothermic (heat is released or “exits”)ENERGY- capacity to do work (supply heat)Exists as:Stored potential energyAn Active motion (kinetic)Temperature (thermal energy)Transfer of thermal is HEAT1st Law of Thermodynamicsenergy cannot be created/destroyedSpontaneity:Chemical Rxns that can occur by themselvesTend to be spontaneous when:Products are less ordered than the reactantsProducts have less potential energy than reactantsIf electrons are held tighter=less potential energyEntropy- amount of disorder in a system2nd law of thermo. States:entropy always increases in an isolated systemChemical/Physical processes proceed in the direction that results in increased entropy and lower potential energyChemical Evolution Theories:Top downExamine modern cells to see chemistry shared throughout the tree of lifeBottom upFocus on small molecules and environmental conditions present in early earthChemical evolution Models:Prebiotic Soup- molecules made from gases or arrived from meteorites, then condensed with rain in the oceans allowing larger molecules to be constructedSurface metabolism- dissolved gases touched minerals on the walls of deep sea vents and formed larger complex moleculesMiller’s experiment:Created early earth’s conditions in a flaskIf molecules reacted with each other, the “rain” would carry them to the mini-oceanThe solution turned deep red and cloudyFound organic compounds and amino acids in there thus proving the prebiotic soup model somewhat possibleThe molecules needed to react with each other would be diluted so the surface metabolism method provided a solutionThe minerals were on the vent walls in the ocean and would attract the gasesCarbon’s importance is based on its versatility:Can form 4 covalent bonds because of its 4 valence electronsLimitless array of shapes can be made possibleCarbo n provides the structural framework for almost all the compounds associated with life, except H2OFunctional Groups:Carbon atoms provide the skeleton but the behavior of organic compounds are changed by groups of other elements…Such as: H,N,O,P,S6 Total GroupsAmino (H2N)Acts as base- attracts a proton to form (attracts an H)Carboxyl (COOH)Acts as an acid- tends to lose a proton (loses the H)Carbonyl (COH or CO)Hydroxyl (OH)Polar so it makes compounds more solubleMay also act as a weak acid and lose a protonPhosphate (PO4)Molecules with more than one P, store a lot of chemical energySulfhydryl (SH)Can form disulfide bonds (S-S) that contribute to protein structureWhen you see an organic compound:Examine size and shape by the carbon frameworkIdentify polar/nonpolar covalent bonds that are formedLocate functional groups and think about the properties of these moleculesAmino Acids:20 totalStructureHydrogen atomNH2- amino functional groupCOOH- carboxyl functional groupR- side group or side chainNonpolar side chains:Mostly feature C-H bondsJust think about electronegativity rules(O>N>C=H)Polar side chains:Look for O-H bondsLook for O-C bonds5 total amino acids in this groupAcidic:Look for negatively charged oxygen atomsBasic chains:Look for positively charged atoms (Nitrogen)Amino Acids to Proteins:Monomers together make polymersPolymerization reaction builds a polymerDehydration (condensation reaction)- remove a H2O molecule to build a polymerPeptide bondC-N covalent bond between amino and carboxyl groupsHydrolysis- add a H2O molecule to separate a polymer into monomersSmall chains of amino acids are oligopeptides; large chains are polypeptides or proteinsPrimary Structure- sequence of amino acidsOne change can cause radical changes in behavior of the proteinFundamental to higher levels of protein structureSecondary Structure- created by H bonds b/w components of the peptide bonded backboneOnly possible when sections of the same backbone put N-H and C=O groups close to each