1. Atoms, Molecules and Macromolecules Building Complex Molecules That Comprise Living Things Prof. Mary Colavito & Dr. John Shepanski

2. Comparison of Terms Element Substance that cannot be broken down to another substance with different properties Atom Smallest unit that has characteristic properties of the element Molecule Two or more atoms joined by chemical bonds Macromolecule Large polymer made of monomer units

3. Composition of an Atom NucleusNucleus Proton = positively charged particle (+) Proton = positively charged particle (+) Neutron = uncharged particle (n or +) Neutron = uncharged particle (n or +) Number of protons + Number of neutrons = Atomic mass Number of protons = Atomic number C12 6 Electrons = negatively charged particlesElectrons = negatively charged particles Number of electrons = Number of protons Each electron circles the nucleus in an orbit representing a specific energy level.

4. Atomic Models Hydrogen (H) Helium (He) Nucleus Electron Shell

5. Different Kinds of Atoms Helium Max 2e - Carbon +7p + +4p + +2p + Innermost electron shell +4e - +4n ± +2n ± +2e - Oxygen Max 8e - +7e - +8n ± Phosphorus +5p + +5e - +4n ± Calcium 2e- 2n 2p+ 6e- 6n 6p+ 8e- 8n 8p+ 15e- 16n 15p+ 20e- 20n 20p+

7. http:// www.sciencegeek.net/tables/lbltable.pdf

8. Electron Energy Levels Energy Level Capacity for Electrons 12 28 3 18 (8*) *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.

9. Chemical Bonds BondCharacteristics Ionic One atom loses an electron, another gains an electron Covalent Atoms share electrons PolarCovalent Electrons are shared unequally Hydrogen Covalently-bound hydrogen is attracted to another atom

10. ± + – ± + ±+ ± +± + ± + ± + ± + – – –– – – ± + – – – ± + – ± + ±+ ± +± + ± + ± + ± + – – –– – – ± + – – – – – – – – – – Ionic Bonding in NaCl ± + – ± + ±+ ± +± + ± + ± + ± + – – –– – – ± + – – –– Sodium #electrons=11 ± + – ± + ±+ ± +± + ± + ± + ± + – – –– – – ± + – – – ––– – – – – Chlorine #electrons=17 – – Sodium ion #electrons=10 Chlorine #electrons=18 – Electron Completely Transferred Negative charge Positive charge

11. Ionic Bonding in NaCl Cl - Na + Ion: charged atom with unequal numbers of protons and electrons.Ion: charged atom with unequal numbers of protons and electrons. Ions of opposite charges attract.Ions of opposite charges attract. Sodium ions nestle between chlorine ions.Sodium ions nestle between chlorine ions. Perfectly cubical crystals form.Perfectly cubical crystals form. Cl - Na +

12. Covalent Bonding Oxygen Atom Oxygen Molecule (O 2 ) Oxygen Molecule (O 2 )

17. In Water, Polar Covalent Bonds Join Oxygen and Hydrogen

18. Hydrogen Bonds Join Water Molecules O O H H H H + + + – – + + Hydrogen Bonds Water molecules are dipoles—the hydrogen side is more positive; the oxygen side is more negative Hydrogen bonds form between O of one water molecule and H of another

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

20. Organic Molecules Contain Carbon Hydrophobic Not attracted to water & non-polar substances Hydrophilic Attracted to water, polar and ionic substances Each carbon atom can make four covalent bonds with other types of atoms or additional carbons.

23. Macromolecules: Polymers Made of Repeating Monomers Macromolecule Monomer Unit CarbohydratesSugars Lipids Fatty acids Proteins Amino acids Nucleic Acids Nucleotides

24. Synthesis and Breakdown of Macromolecules Condensation Synthesis Removal of water to add monomer units Hydrolysis Addition of OH and H groups of water to break a bond between monomers

25. Dehydration Synthesis / Hydrolysis Dehydration Synthesis Hydrolysis

26. Carbohydrates: Structure SimpleSimple –Monosaccharides= one sugar unit Glucose = blood sugar All cells use glucose for energy

27. Carbohydrates: Structure HOH CH 2 OH H HO H OH H HO HH O O HOCH 2 H CH 2 OH HHO HHO O H HO H OH H HO H OH H O Glucose O HOCH 2 H CH 2 OH HHO HO HHO Fructose Sucrose & Water ++ SimpleSimple –Disaccharides = two sugar units –Examples: sucrose, lactose, maltose

28. Carbohydrates: Structure ComplexComplex –Polysaccharides= many sugar units Starch -- storage in plantsStarch -- storage in plants Glycogen -- storage in animalsGlycogen -- storage in animals Cellulose -- plant cell walls, indigestibleCellulose -- plant cell walls, indigestible

29. Carbohydrates: Structure Complex – –Polysaccharides= many sugar units found in plant cell walls energy storage in animals energy storage in plants

30. Carbohydrates: Functions Energy sourceEnergy source Structural componentStructural component Cell-cell communicationCell-cell communication

31. Lipids: Structure Polar Head Glycerol Fatty Acid Tails HydrophobicHydrophilic Phospholipid— component of cell membranes Phospholipid— component of cell membranes

32. Lipids: Structure Types of Fatty AcidsTypes of Fatty Acids –Saturated – 2H per internal carbon –Unsaturated -- <2H per internal carbon  one or more double bonds Monounsaturated – one double bondMonounsaturated – one double bond Polyunsaturated – more than one double bondPolyunsaturated – more than one double bond

33. Which Is a Source of Unsaturated Fatty Acids? Linseed Oil Beef Fat

34. Lipids: Functions Concentrated energy sourceConcentrated energy source Structural components of cell membranesStructural components of cell membranes –Phospholipids –Cholesterol CommunicationCommunication –Steroid Hormones MetabolismMetabolism –Fat-soluble vitamins InsulationInsulation Protection from waterProtection from water –Waxes Cholesterol Phospholipids

35. Per 23 chromosomes Now estimated at 30,000 genes

36. DNA RNA Protein Information Flow From DNA transcription translation replication (before cell duplicates) (ongoing parts of cell metabolism) Gene: sequence of DNA that codes for a protein

37. DNA and RNA Structure DNA DNA RNA RNA Primary Structure Chain of nucleotides Secondary Structure Double helix Single folded chain Nucleotide = phosphate + sugar + nitrogen-containing base

38. DNA Replication DNA chains separateDNA chains separate Each chain is used as a pattern to produce a new chainEach chain is used as a pattern to produce a new chain Each new DNA helix contains one “old” and one “new” chainEach new DNA helix contains one “old” and one “new” chain

39. Transcription = Production of RNA Using DNA as a Template DNA chains separateDNA chains separate ONE DNA chain is used as a pattern to produce an RNA chainONE DNA chain is used as a pattern to produce an RNA chain RNA chain is released and the DNA chains reform the double-helixRNA chain is released and the DNA chains reform the double-helix In DNA In RNA A U T A G C C G

40. Transcription  Protein Synthesis Messenger RNAMessenger RNA Contains 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 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 proteinsAt sub-cellular structures called ribosomes, RNA code is used to guide the assembly of proteins

41. Four Levels of Protein Structure Primary (Sequence) Secondary (Coiling by Hydrogen Bonding) Tertiary (Folding by R-group interactions) Quaternary (Two or more chains associating)

42. Proteins: Structure Amino Group Amino Group The “R” Group Differs for Each Amino Acid Carboxylic Acid Group Central Carbon R Primary structure = chain of amino acidsPrimary structure = chain of amino acids –Amino acids have common features

43. Proteins: Structure Forming the Protein Chain Dehydration Synthesis between COOH & NH 2 Phenylalanine Leucine

45. Secondary structure governed by hydrogen bonds

46. Tertiary structure governed by attraction/repulsion of R-groups

47. Four Levels of Protein Structure Quaternary Structure:Quaternary Structure: Association of two or more protein chains Association of two or more protein chains eg. Hemoglobin is composed of 4 protein chains eg. Hemoglobin is composed of 4 protein chains 2 are called alpha hemoglobin 2 are called alpha hemoglobin 2 are called beta hemoglobin 2 are called beta hemoglobin

48. Cell Membrane

49. The Cell

50. Tissues & Organs Lung Tissue

51. Neurons

52. The Brain The Most Complex Assembly Of Matter Of Which We Know