THE CHEMISTRY OF LIFE

1. THE CHEMISTRY OF LIFE CHAPTER 2 Honors Notes

2. SECTION 2-1: THE NATURE OF MATTER • REMEMBER… • Atoms are made up of electrons (-), neutrons (neutral), and protons (+) • Proton number = atomic number = type of element • Isotope – atoms of same element, but with a different number of neutrons

3. Bonds • Ionic bond – when electrons are transferred from one atom to another • Example NaCl • Covalent bond – electrons are shared between atoms • Example H2O

4. COVALENT BOND #’S • Atoms want to fill their electron shells. An atom wants to make just enough bonds to fill its shells. • H makes one bond • O makes two bonds • C makes four bonds

5. Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-) Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1

6. SECTION 2-2: PROPERTIES OF WATER • Polarity – uneven distribution of electrons between the hydrogen and oxygen atoms • Oxygen is bigger and attracts the electrons more than hydrogen • Hydrogen bonds – slightly positive, polar H atoms are attracted to polar negative atoms like O

7. Cohesion – attraction between molecules of same substance • Water has high surface tension (allows some bugs to walk on water) • Adhesion - attraction between molecules of different substances • Capillary action (water moves up a straw along the sides)

8. Acids, Bases, and pH H2O H+ + OH- Water Proton + hydroxide ion

9. pH scale – indicates the concentration of H+ • pH = 7 = neutral (H+ = OH-) • Base = pH above 7 (lower H+ than pure water) • Acid = pH below 7 (higher H+ than pure water) • Buffer – weak acids or bases that can prevent sharp, sudden changes in pH • Example: bicarbonate

10. http://www.epa.gov/acidrain/education/site_students/phscale.htmlhttp://www.epa.gov/acidrain/education/site_students/phscale.html

11. SECTION 2-3: CARBON COMPOUNDS • Organic compounds- those compounds that contain carbon • Chemical Formulas - show how many and which atoms are in a compound • Structural Formulas - show the arrangement of the atoms in a compound

12. LIFE’S BACKBONE • Most of the compounds that make up living things contain carbon. In fact, carbon makes up the basic structure, or “backbone,” of these compounds. Each atom of carbon has four electrons in its outer energy level, which makes it possible for each carbon atom to form four covalent bonds with other atoms.

13. Carbon’s tetrahedral shape http://www.chem.uic.edu/web1/OCOL-II/WIN/STRUCT/SB/14.HTM

14. Carbon-Carbon bonds can be single, double, or even triple. This bonding characteristic allows for a virtually limitless number of different carbon compounds. Each carbon compound has a different structure. For example, carbon atoms can bond together to form chains that can be straight or branching. They can bond to form single or multiple ring structures. They can even bond to form crystalline or hollow polyhedrons—multi-sided 3 dimentional molecules.

15. Diamond http://users.omskreg.ru/~kolosov/atlas/3D-crystals/images/diamond.gif

16. C-60 “Buckey Ball” http://crystals.ethz.ch/icsd/help/images/buckeyb.jpg

17. A* C B* E D* F H* G* Other Polyhedrons

18. Organic molecules are named using an internationally recognized (IUPAC) system of naming Also, other kinds of atoms can be attached to the carbon chain.

19. Isomers- compounds with the same chemical formula, but different structure (ex. propanol and isopropanol)

21. Functional Groups • Functional groups are like power attachments that change the job (chemical and physical properties) that a molecule does. • We’ve already looked at the hydroxyl –OH group. Now let’s look at some others: • Chemical Compound Formula Name of Compound Example • Esters Esters Methyl salicylate

22. Biology text reference

23. MACROMOLECULES • Monomers (smaller units) join to make polymers or macromolecules • Carbohydrates • Lipids • Proteins • Nucleic acids

24. CARBOHYDRATES • Organic compounds composed of carbon, hydrogen and oxygen with a ratio of two hydrogen atoms to every one oxygen atom • Made up of sugars

25. USE OF CARBOHYDRATES • Source of energy for many living things • Examples: sugar and starch

26. TYPES OF CARBOHYDRATES • Monosaccharides • Disaccharides • Polysaccharides

27. MONOSACCHARIDES • Only one sugar molecule • Examples -glucose, fructose, and galactose • All three are C6H12O6, but they are isomers • Draw Glucose

28. DISACCHARIDES • Double sugars (two monosaccharides combined) • Examples: sucrose, lactose, and maltose • All are isomers with the chemical formula C12H22O11

29. POLYSACCHARIDES • Long chains of monosaccharides joined together • Examples: starch, glycogen, and cellulose • Plants store excess sugar as starch, and break it down for energy

30. Representation of a Polysaccharide

31. Humans store excess sugar as glycogen, & break it down for energy • Cellulose used by plants for structural purposes.

32. DEHYDRATION SYNTHESIS • Two molecules join together by losing a molecule of water

33. HYDROLYSIS REACTION • Larger molecules broken down into smaller molecules by the addition of water

34. LIPIDS • Include fats, oils, steroids & waxes • Composed of carbon, hydrogen and oxygen, but the # of H atoms per molecule is much greater then the # of O atoms • An example, C57H110O6

35. USES OF LIPIDS • Stored for energy • Form basic structure of cell membranes • Protection • Insulation • Waterproof coverings

36. THE STRUCTURE OF SOME FATS • Built from 2 basic molecules: • Glycerol- an alcohol • Fatty Acids - a long carbon chain with a -COOH (carboxyl group) at one end

37. Triglyceride Structure http://library.tedankara.k12.tr/chemistry/vol5/Proteins%20peptides%20fats%20structure%20heme%20proteins/z245.htm

38. Phospholipid Structure http://library.tedankara.k12.tr/chemistry/vol5/polarity%20and%20activity/z247.htm

39. Different types of fatty acids: • Saturated- all single, covalent bonds in between carbons in chain • Unsaturated - one double bond between carbons in chain

40. Polyunsaturated - many double bonds between carbons in chain • Cholesterol - another lipid, made by animals, both helpful & harmful

41. PROTEIN • Made up of amino acids linked together • Composed of C, H, & O as well as nitrogen, N, and possibly sulfur

42. USES OF PROTEINS • build living materials like muscle • act as enzymes to help carry out chemical reactions • fight disease • transport particles into or out of cells • act as markers on cells

43. General structure Serine Alanine

44. There are 20 main amino acids • Each has same basic structure with the only difference being the “R” group • Amino acids are linked by peptide bonds (formed by dehydration synthesis) Essential Amino Acids

45. Peptide bond is between two amino acids • Polypeptide– (a protein) many amino acids joined

46. Amino acids

47. Nucleic Acids • Nucleic Acids are molecules that are used for the storage of energy or information. • Some examples of Nucleic Acids are DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and ATP (adenosine triphosphate) • Nucleic Acids are made of monomers called NUCLEOTIDES.

48. Nucleotides http://dnatesting.biz/nucleotides.png

49. DNA 3D

50. MATTER AND ENERGY • Have you ever sat around a campfire or watched flames flicker in a fireplace? The burning of wood is a chemical reaction—a process that changes one set of chemicals into another set of chemicals. A chemical reaction always involves changes in chemical bonds that join atoms in compounds. The elements or compounds that enter into a chemical reaction are called reactants. The elements or compounds produced by a chemical reaction are called products. As wood burns, molecules of cellulose are broken down and combine with oxygen to form carbon dioxide and water vapor, and energy is released.