Observations Hypothesis Predictions Experiments or new predictions THEORYLiving organism characteristics:ComplexityAbility to change to environmentAbility to reproduceCapacity to evolveSpontaneous CreationLouis Pasteur à things created from previously created living things (spontaneous creation did not occur with micro organisms)Swan neck glasses à curve in the neckMicroorganisms fall into straight neck flask, not into the swan neck flask (settle in the bottom of curve)Essentials of a CellCan store and transmit informationHas a plasma membraneCan harness energy from the environment sunlight & chemical compoundsEvolutionGenetic variation, mutation in DNADifferential reproductionFavored traits can reproduce the mostVariation is environmental or geneticTree of LifeEukaryotes humans, animals, plants, protists, fungiArchaea & Bacteria prokaryotes, lack a nucleusHydrophilic“water-loving”Readily dissolve in waterMolecules that contain ionic and/or polar covalent bondsHydrophobic“water-fearing”Do not readily dissolve in waterNonpolar molecules like hydrocarbons (only C & H)Amphipathic moleculeHave both polar/ionized and nonpolar regionsHydrophobic Effect polar molecules (like water) exclude nonpolar onesORGANIC MOLECULES CARBON, most are polymers (large molecules)Carbons in the sugar numbered with primes (1’, 2’)Carbons in the base numbered (1, 2)Proteinscomposed of amino acidslinked covalently thru peptide bonds, loss of H2Oform a polypeptide chain proteinprovide structural support, act as catalystscellular proteins are composed of 20 amino acidsNucleic AcidsNucleotides5 carbon sugarbaseone or more phosphate groupsencode and transmit genetic information thru nucleotide sequenceDNA deoxyribonucleic aciddeoxyribose sugar H on 2’RNA ribonucleic acidRibose sugar OH on 2’pyridmidine: single ring bases T, C, Upurine: double ring bases A, Gphosphodiester bond: link nucleotides together, loss of H2OCarbohydratesComplex carbohydrates composed of simple sugarsComposed of C, H, O, usually 1:2:1Simplest carbohydrates: saccharidesLinear, 5-6 C atomsC6H12O6Monosaccharide: simple sugarAldehyde group aldosesKetone group ketosesDisaccharide: two simple sugars, covalently bondedPolysaccharides: simple sugars linked together, covalentlyComplex carbohydrates: long branched chains of monosaccharidesGlycosidic bonds: monosaccharides attached to each other, covalently, loss of H2OLipidsfatty acid: long chain of carbons attached to carboxyl group at endcarboxyl: COOHSaturatedno double bonds“saturated with H”straight chainshigher MP than unsaturatedUnsaturatedC-C double bonds“unsaturated with H”kink at each double bondlower MP than saturatedmake up cell membranes, store energy, act as signaling moleculesdefined by property rather than chemical structure lipids are all hydrophobicVan der Waals forces constant motion of electrons, regions of slight positive and negative charge, weaker than H bonds, act together to stabilize molecules1. Triacylglycerolfatty acid + glycerolUsed for energy storageCan be any length2. SteroidsEx: cholesterolCore of 20 carbons 4 fused ringsAnimal cell membranes3. PhospholipidsMajor component of cell membraneGlycerol + fatty acid + molecule w/ phosphate groupPhosphate head group is hydrophilicFatty acid tail is hydrophobicCreate bilayer in aqueous solutionGriffith Experiment Genetic materialPneumonia virusKilled virulent + non-virulent bacteria mixed mouse diesTransformation of non-virulent cells virulent cellsAvery, Macleod, McCarty Experiement Genetic material3 enzymesDestroy RNADestroy DNADestroy ProteinTreated non-virulent bacteria with enzymes and tested for non-virulent virulent transformationTreated with enzyme that destroys DNA only one that was unable to transform to virulent bacteriaDNA is molecule responsible for transforming non-virulent virulentKey evidence that DNA is genetic materialProkaryotes: transcription and translation in the cytoplasmEukaryotes: transcription in nucleus and translation in the cytoplasmNUCLEOTIDES 5 carbon sugar, base, one or more phosphate groupsNegative charges on 2 O atoms in phosphate groups makes DNA a mild acidNucleoside base + sugarNucleotide base + sugar + phosphate groupNucleoside monophosphate base + sugar + phosphate groupNucleoside diphosphate base + sugar + 2 phosphate groupsNucleoside triphosphate base + sugar + 3 phosphate groupsUsed to make nucleotide polymers (DNA, RNA) and carriers of chemical energy (ATP, GTP)Phosphodiester bond: stable bond in DNA, withstand heat/changes in pHC-O-P-O-C linkage in the actual bond5’ 3’, read as “5’-AGCT-3’ ”Gives DNA strand polarityDouble HelixSugar phosphate backboneMajor/minor grooves10 base pairs per complete turnIndividual DNA strands are antiparallel run in opposite directions 3’ end of one strand is opposite the 5’ end of the otherEach base pair purine + pyrimidineHydrogen BondingH bonds hold together base pairsA=T, 2 hydrogen bondsG=C, 3 hydrogen bondsBase stacking non polar, flat surfaces of bases tend to group together away from water molecules stack on top of each other as tightly as possible important stabilizing forceCellular DNA is coiled and packaged with proteinsIn prokaryotic cells: DNA molecules are circular and form supercoils circular molecule coils upon itself caused by enzymes (topoisomerases) that put strain on the double helix supercoils relieve the strainIn eukaryotic cells: DNA molecules in nucleus are linear each individual molecule forms one chromosomeDNA molecules packaged with proteins (histones) into a 30-nm chromatin fiberPlaces where transcription is actively taking place 30-m fiber relaxes 10-nm chromatin fiberBoth fibers ChromatinFiber is made of nucleosome core particle bead like repeating unit contains 2 of each histone proteins (H2A, H2B, H3, H4) rich in positively charged amino acids lysine and arginine forms ionic bond with negatively charged sugar phosphate backbone of DNA DNA double helix wraps twice around core particleThe Scientific Method 02/26/2014Observations Hypothesis Predictions Experiments or new predictions THEORYLiving organism characteristics:- Complexity- Ability to change to environment- Ability to reproduce- Capacity to evolveSpontaneous Creation- Louis Pasteur
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