BIOL 240 1st Edition Lecture 2Outline of Last Lecture I. Mattera. Elementsb. Compounds Vs. Moleculesc. Atoms and their essential partsi. The functions of the essential partsd. Energy levels of electronsi. Chemical behavior due to electronsII. Chemical bondsa. Covalentb. Ionicc. Single bond vs. double bondd. ElectronegativityOutline of Current Lecture Water and CarbonI. Importance of watera. Four properties of waterII. Water lovers/hatersa. Hydrophilicb. HydrophobicAcids and BasesI. General process of acids and basesII. Strong acids and basesa. What determines if it’s strongIII. Weak acids and basesa. What determines if it’s weakIV. The pH scalea. How to calculate pHV. Buffersa. Human bloodCurrent LectureWater and CarbonThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.III. Importance of watera. Living things consist 70%-80% of waterb. Has polar covalent bonds making it a polar moleculec. Has hydrogen bonds between molecules: allows transport against gravity in plantsi. Hydrogen bonds contribute to four properties of water1. Cohesion/Adhesiona. Cohesion: the attraction of water molecules to other watermolecules (Result: water pulled up a tree by evaporation)i. Surface tension: resists against penetration of waterb. Adhesion: the attraction of water molecules to cell walls ofother molecules (Result: water stabilizes itself up the tree by attaching to the inside of the trunk)2. Moderate temperaturesa. Water has high specific heati. Heat: kinetic energy transferii. Specific heat: heat gained/lost for 1 gram to changeby 1 degreeb. Allows lifei. Our bodiesii. Costal temperatures have less drastic temperature changesc. Evaporative cooling: transformation from liquid to gasi. Evaporation: surface coolingii. Stabilizes our temperatureiii. Effect of high humidityiv. Fact: humans can last 8-minutes at 212 degrees Fahrenheit3. Expansion upon freezinga. Hydrogen bonds in ice are more ordered making ice less dense than liquid water, allowing ice to floatb. If ice sank, water would eventually freeze solid making life impossiblec. Ice: hydrogen bonds are stabled. Liquid: hydrogen bonds break and re-form4. Versatility as a solventa. Water is partially positive and partially negative creating a hydration shell (water molecules surround solute)b. Solvent: dissolves the solutec. Solute: the substance being dissolvedd. Aqueous solution: water is the solvente. Water dissolves:i. Non-ionic polar molecules (sugars)ii. Large polar molecules with ionic/polar molecules (proteins)f. Water does not dissolve:i. Nonpolar molecules (lipids)IV. Water lovers/hatersa. Hydrophilic: water loverb. Hydrophobic: water haterAcids and BasesVI. General processa. H+ ions are transferred to another water (hydronium)b. Leaves hydroxide (OH-) behindc. H+ represents the hydronium iond. H+ in wateri. Basic: OH-> H+ii. Neutral: OH- = H+iii. Acidic: OH-< H+VII. Strong acids and basesa. Strong acid dissociates completely in waterb. Strong base dissociates completely in waterVIII. Weak acids and basesa. Weak acids/bases are reversiblei. Weak base: Ammonia1. NH3 + H+ NH4+ii. Weak acid: Carbonic acid1. H2CO3 HCO3- + H+IX. The pH scalea. The measurement of how basic/acidic a substance isi. The product of H+ and OH- is constant1. [H+][OH-]= 10-14ii. pH of a solution is pH=-log[H+]iii. pH + pOH = 17X. Buffersa. The internal pH of most living cells must remain close to pH 7b. Buffer: combats H+ or OH- that would change the pHc. Human blood: carbonic acid is a buffer in human bloodi. H2CO3 HCO3- + H+ 1. Response to a rise in pH: H2CO3 HCO3- + H+2. Response to a drop in pH: H2CO3 HCO3- +