Atoms, Molecules and Macromolecules

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Atoms, Molecules and Macromolecules. Building Complex Molecules That Comprise Living Things. Prof. Mary Colavito & Dr. John Shepanski. Comparison of Terms. C. 12. 6. Composition of an Atom. Nucleus Proton = positively charged particle (+) - PowerPoint PPT Presentation

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Atoms, Molecules and Macromolecules Building Complex Molecules That Comprise Living ThingsProf. Mary Colavito& Dr. John ShepanskiComparison of Terms Composition of an Atom Nucleus Proton = positively charged particle (+) Neutron = uncharged particle (n or +)Number of protons + Number of neutrons = Atomic massNumber of protons = Atomic number Electrons = negatively charged particlesNumber of electrons = Number of protons Each electron circles the nucleus in an orbit representing a specific energy level.Atomic ModelsHydrogen (H)Helium (He)NucleusElectron ShellChapter 2Different Kinds of AtomsHeliumMax 2e-Carbon+7p++4p+ +2p+Innermost electron shell+4e-+4n+2n+2e-OxygenMax 8e-+7e-+8nPhosphorus+5p++5e-+4nCalcium2e- 2n 2p+6e- 6n 6p+8e- 8n 8p+15e- 16n 15p+20e- 20n 20p+Chapter 2http://www.sciencegeek.net/tables/lbltable.pdf Electron Energy Levels*In forming molecules, atoms combine to fill their outer (valence) energy levels. When 8 valence orbitals are filled, remaining, unused slots available in inner levels are filled before a new valence shell is added.Chemical BondsIonic Bonding in NaClSodium ion #electrons=10Chlorine #electrons=18Negative chargePositive chargeChapter 2Ionic Bonding in NaClIon: charged atom with unequal numbers of protons and electrons.Ions of opposite charges attract.Sodium ions nestle between chlorine ions.Perfectly cubical crystals form.Chapter 2Covalent BondingOxygen AtomOxygen AtomOxygen Molecule (O2)In Water, Polar Covalent Bonds Join Oxygen and Hydrogen Hydrogen Bonds Join Water MoleculesOOHHHH+++++Hydrogen BondsWater molecules are dipolesthe hydrogen side is more positive; the oxygen side is more negativeHydrogen bonds form between O of one water molecule and H of another Chapter 2Due to hydrogen bonding, ionic and polar substances dissolve in waterOrganic Molecules Contain CarbonEach carbon atom can make fourcovalent bonds with other types of atoms or additional carbons. Macromolecules: Polymers Made of Repeating MonomersSynthesis and Breakdown of Macromolecules Dehydration Synthesis / HydrolysisDehydration SynthesisHydrolysisCarbohydrates: StructureSimpleMonosaccharides= one sugar unitGlucose = blood sugarAll cells use glucose for energyCarbohydrates: StructureSimpleDisaccharides = two sugar unitsExamples: sucrose, lactose, maltoseSucrose & WaterCarbohydrates: StructureComplexPolysaccharides= many sugar unitsStarch -- storage in plantsGlycogen -- storage in animalsCellulose -- plant cell walls, indigestibleCarbohydrates: StructureComplexPolysaccharides= many sugar unitsCarbohydrates: FunctionsEnergy sourceStructural component Cell-cell communication Lipids: StructurePolar HeadGlycerolFatty Acid TailsHydrophobicHydrophilic Phospholipidcomponent of cell membranesLipids: StructureTypes of Fatty Acids Saturated 2H per internal carbonUnsaturated -- Which Is a Source of Unsaturated Fatty Acids?Linseed OilBeef Fat Lipids: FunctionsConcentrated energy sourceStructural components of cell membranesPhospholipids Cholesterol CommunicationSteroid HormonesMetabolismFat-soluble vitaminsInsulationProtection from waterWaxes CholesterolPhospholipidsDNARNAProteinInformation Flow From DNA(ongoing parts of cell metabolism)Gene: sequence of DNA that codes for a proteinDNA and RNA StructureNucleotide = phosphate + sugar + nitrogen-containing base DNA RNAPrimary StructureChain of nucleotidesChain of nucleotidesSecondary StructureDouble helixSingle folded chainDNA ReplicationDNA chains separateEach chain is used as a pattern to produce a new chainEach new DNA helix contains one old and one new chainTranscription = Production of RNA Using DNA as a Template DNA chains separateONE DNA chain is used as a pattern to produce an RNA chainRNA chain is released and the DNA chains reform the double-helixIn DNA In RNA A U T A G C C GTranscription Protein Synthesis Messenger RNAContains the code words for the sequence of amino acids in a specific protein CODON = group of three nucleotides acting as a code word for a protein amino acidAt sub-cellular structures called ribosomes, RNA code is used to guide the assembly of proteinsFour Levels of Protein StructureProteins: StructurePrimary structure = chain of amino acidsAmino acids have common featuresAmino GroupThe R Group Differs for Each Amino AcidCarboxylic Acid GroupCentral CarbonRProteins: Structure Forming the Protein ChainDehydration Synthesis between COOH & NH2PhenylalanineLeucineSecondary structuregoverned by hydrogen bondsTertiary structure governed byattraction/repulsion of R-groupsFour Levels of Protein StructureQuaternary Structure: Association of two or more protein chains eg. Hemoglobin is composed of 4 protein chains 2 are called alpha hemoglobin 2 are called beta hemoglobinCellMembraneThe CellTissues & OrgansLung TissueNeuronsThe BrainThe MostComplex AssemblyOf MatterOf WhichWe KnowDepending on the sequence of amino acids, the polypeptide chain can either form a spiral like the tube on the left, or a pleated sheet like on the right.Some proteins have a spiral section followed by a sheet section, etc.Fig 2.26, p35.See p 34Here we position two amino acids close together so that the amine group of one is close to the carboxyl group of the other.Note that a -H is hanging out from one, and a -OH from the other.These will be broken off (by an enzyme) to form water.The remaining bonds of the two amino acids will be connected to form a dipeptide (two amino acids joined by a peptide linkage).

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