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


  • Atoms, Molecules and Macromolecules Building Complex Molecules That Comprise Living ThingsProf. Mary Colavito& Dr. John Shepanski

  • Comparison 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 Shell

    Chapter 2

  • Different 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 2


  • 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 Bonds

  • Ionic Bonding in NaClSodium ion #electrons=10Chlorine #electrons=18Negative chargePositive charge

    Chapter 2

  • Ionic 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 2

  • Covalent 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 2

  • Due to hydrogen bonding, ionic and polar substances dissolve in water

  • Organic Molecules Contain CarbonEach carbon atom can make fourcovalent bonds with other types of atoms or additional carbons.

  • Macromolecules: Polymers Made of Repeating Monomers

  • Synthesis and Breakdown of Macromolecules

  • Dehydration Synthesis / HydrolysisDehydration SynthesisHydrolysis

  • Carbohydrates: StructureSimpleMonosaccharides= one sugar unitGlucose = blood sugarAll cells use glucose for energy

  • Carbohydrates: StructureSimpleDisaccharides = two sugar unitsExamples: sucrose, lactose, maltoseSucrose & Water

  • Carbohydrates: StructureComplexPolysaccharides= many sugar unitsStarch -- storage in plantsGlycogen -- storage in animalsCellulose -- plant cell walls, indigestible

  • Carbohydrates: StructureComplexPolysaccharides= many sugar units

  • Carbohydrates: FunctionsEnergy sourceStructural component Cell-cell communication

  • Lipids: StructurePolar HeadGlycerolFatty Acid TailsHydrophobicHydrophilic Phospholipidcomponent of cell membranes

  • Lipids: StructureTypes of Fatty Acids Saturated 2H per internal carbon

    Unsaturated --

  • 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 CholesterolPhospholipids

  • DNARNAProteinInformation Flow From DNA(ongoing parts of cell metabolism)Gene: sequence of DNA that codes for a protein

  • DNA and RNA StructureNucleotide = phosphate + sugar + nitrogen-containing base

    DNA RNAPrimary StructureChain of nucleotidesChain of nucleotidesSecondary StructureDouble helixSingle folded chain

  • DNA ReplicationDNA chains separate

    Each chain is used as a pattern to produce a new chain

    Each new DNA helix contains one old and one new chain

  • Transcription = Production of RNA Using DNA as a Template DNA chains separate

    ONE DNA chain is used as a pattern to produce an RNA chain

    RNA chain is released and the DNA chains reform the double-helixIn DNA In RNA A U T A G C C G

  • Transcription 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 acid

    At sub-cellular structures called ribosomes, RNA code is used to guide the assembly of proteins

  • Four Levels of Protein Structure

  • Proteins: StructurePrimary structure = chain of amino acidsAmino acids have common featuresAmino GroupThe R Group Differs for Each Amino AcidCarboxylic Acid GroupCentral CarbonR

  • Proteins: Structure Forming the Protein ChainDehydration Synthesis between COOH & NH2PhenylalanineLeucine

  • Secondary structuregoverned by hydrogen bonds

  • Tertiary structure governed byattraction/repulsion of R-groups

  • Four 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 hemoglobin

  • CellMembrane

  • The Cell

  • Tissues & OrgansLung Tissue

  • Neurons

  • The BrainThe MostComplex AssemblyOf MatterOf WhichWe Know

    Depending 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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