1. BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor From PowerPoint ® Lectures for Biology: Concepts & Connections The Chemical Basis of Life MACROMOLECULES

2. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings chemical element - substance that cannot be broken down to other substances by ordinary chemical means / smallest form = atom About 25 different chemical elements essential to life ELEMENTS

3. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Carbon, hydrogen, oxygen, and nitrogen make up the bulk of living matter, but there are other elements necessary for life Table 2.2

4. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Goiters are caused by iodine deficiency Figure 2.2

5. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Compound: elements bonded in fixed ratio Example: sodium (Na)+ chlorine (Cl)  sodium chloride (NaCl) Elements can combine to form compounds

6. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 2 Bonds Ionic – exchanging electrons Covalent – sharing electrons nonpolar covalent = equal sharing polar covalent = unequal sharing

7. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –oxygen end of the molecule slightly (-) charged –hydrogen end of the molecule is slightly (+) charged –Water = polar molecule water molecule, oxygen stronger pull on the shared electrons than hydrogen Figure 2.9 (–) O (+) HH

8. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hydrogen bond: molecules (not elements) attracted because one part (+) while other molecule part (-) Weak bond Overview: Water’s polarity leads to hydrogen bonding and other unusual properties Figure 2.10A Hydrogen bond

9. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings B/c hydrogen bonding, water molecules move up in plants (adhesion) surface tension created by cohesive water molecules (insect walk on barrier) Hydrogen bonds make liquid water cohesive Figure 2.11

10. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Acid = (H+) Base = (OH-) Acidity measured on pH scale: –0-7 acidic –8-14 basic –Pure water / neutral pH = 7 ACIDS and BASES

11. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The pH scale Figure 2.15 pH scale Acidic solution Neutral solution Basic solution Increasingly ACIDIC (Higher concentration of H + ) Increasingly BASIC (Lower concentration of H + ) NEUTRAL [H + ] = [OH – ] Lemon juice; gastric juice Grapefruit juice Tomato juice Urine PURE WATER Seawater Milk of magnesia Household ammonia Household bleach Oven cleaner Human blood H+H+ OH –

12. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Buffers: substances that resist pH change – Either accept or donate H+ ions depending on situation to keep original pH

13. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hemoglobin buffer Figure 22.11A TISSUE CELL CO 2 produced INTERSTITIAL FLUID CO 2 BLOOD PLASMA WITHIN CAPILLARY Capillary wall H2OH2O H 2 CO 3 Carbonic acid RED BLOOD CELL HCO 3 – +H+H+ Hemoglobin picks up CO 2 and H + Bicarbonate HCO 3 –

14. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Compound that has Carbon Synthesized by living organism Ex. CO 2 NOT organic, C 6 H 12 O 6 organic Organic Compound Figure 3.1, top part

15. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Functional groups (ex): OH hydroxyl C=O Carbony COOH Carboxyl NH2 Amino Functional groups help determine the properties of organic compounds

16. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Table 3.2

17. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Monomer + Monomer (etc) = Polymer (macromolecule) 4 Macromolecules: –Carbohydrates –Lipids –Proteins –Nucleic Acids Macromolecules

18. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Dehydration Synthesis – making polymer by removing water 123 Unlinked monomer Removal of water molecule 1234 Longer polymer Figure 3.3A Short polymer

19. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hydrolysis: breaking polymer by adding water Coating of capture strand 123 Addition of water molecule 123 Figure 3.3B 4

20. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Carbohydrates: short term energy –Monomer: monosaccharide –Polymer: Polysaccharides CARBOHYDRATES

21. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ratio of CH 2 O contains hydroxyl groups and a carbonyl group Monosaccharides :fuels for cellular work Monosaccharides: simplest carbohydrates Figure 3.4A

22. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ex. monosaccharides glucose and fructose are isomers –contain the same atoms but in different arrangements GlucoseFructose Figure 3.4B

23. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Many monosaccharides form rings, as shown here for glucose Abbreviated structure Figure 3.4C

24. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Disaccharide = Monosaccharides + Monosaccharides ex sucrose (table sugar) and maltose (brewing sugar) Cells link single sugars to form disaccharides Glucose Maltose Figure 3.5 Sucrose

25. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Polysaccharides: 100s of monomers linked Animal: glycogen Plant: Cellulose and starch Figure 3.7 Starch granules in potato tuber cells Glucose monomer STARCH GLYCOGEN CELLULOSE Glycogen granules in muscle tissue Cellulose fibrils in a plant cell wall Cellulose molecules

26. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings composed largely of carbon and hydrogen –not true polymers –do not mix with water –Mostly nonpolar Lipids Figure 3.8A

27. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings lipids main function energy storage –also called triglycerides triglyceride molecule = one glycerol molecule linked to three fatty acids Figure 3.8B Fatty acid

28. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phospholipids = major component of cell membranes Waxes form waterproof coatings Steroids are often hormones Examples of Lipids: Phospholipids, waxes, and steroids are lipids with a variety of functions Figure 3.9

29. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Proteins involved in –cellular structure –movement –defense –transport –Communication Enzymes regulate chemical reactions PROTEINS Proteins are essential to the structures and activities of life Figure 3.11

30. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings FORM FITS FUNCTION Protein’s function determined by shape –Monomer = amino acids Proteins are made from just 20 kinds of amino acids

31. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Amino acid contains: –amino group –carboxyl group –an R group, which distinguishes each of the 20 different amino acids Amino group Carboxyl (acid) group Figure 3.12A

32. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Each amino acid has specific properties Leucine (Leu) Figure 3.12B Serine (Ser)Cysteine (Cys) HYDROPHOBICHYDROPHILIC

33. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Cells link amino acids together by dehydration synthesis bonds between amino acid = peptide bonds Amino acids can be linked by peptide bonds Amino acid Dipeptide Dehydration synthesis Carboxyl group Amino group PEPTIDE BOND Figure 3.13

34. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings shape determines the protein’s function –Denature: protein loses its specific function when its polypeptides unravel –Caused by extreme pH, temperature, salinity Overview: A protein’s specific shape determines its function Figure 3.14AFigure 3.14B

35. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A protein’s primary structure = amino acid sequence Secondary structure = polypeptide coiling or folding produced by hydrogen bonding Figure 3.15, 16 Amino acid Hydrogen bond Alpha helix Pleated sheet Primary structure Secondary structure

36. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Tertiary structure = overall shape of a polypeptide Quaternary structure = relationship among multiple polypeptides of a protein Figure 3.17, 18 Polypeptide (single subunit of transthyretin) Transthyretin, with four identical polypeptide subunits Tertiary structure Quaternary structure

37. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Activation Energy – energy needed for reaction to get started (E A ) Enzymes speed up reactions by lowering energy barriers HOW ENZYMES WORK

38. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings protein catalyst - enzyme - decrease the energy barrier E A barrier Reactants 1Products2 Enzyme Figure 5.5A

39. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings E A with enzyme Figure 5.5B Reactants Products E A without enzyme Net change in energy

40. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Enzymes selective because of Active Site A specific enzyme catalyzes each cellular reaction

41. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Enzyme (sucrase) Active site 1 2 3 Substrate (sucrose) Enzyme available with empty active site Substrate binds to enzyme with induced fit Substrate is converted to products 4 Products are released GlucoseFructose How an enzyme works The enzyme is unchanged and can repeat the process Figure 5.6

42. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Enzyme activity is influenced by –temperature –salt concentration –pH Some enzymes require nonprotein cofactors –Some cofactors are organic molecules called coenzymes The cellular environment affects enzyme activity

43. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Inhibitors interfere with enzymes –competitive inhibitor: takes the place of a substrate in the active site –noncompetitive inhibitor: alters an enzyme’s function by changing its shape Enzyme inhibitors block enzyme action Substrate Enzyme Active site NORMAL BINDING OF SUBSTRATE Competitive inhibitor Noncompetitive inhibitor ENZYME INHIBITION Figure 5.8

44. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Nucleic acids ( DNA and RNA ) serve as the blueprints for proteins Ultimately control the life of a cell NUCLEIC ACIDS Nucleic acids are information-rich polymers of nucleotides

45. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings monomers of nucleic acids = nucleotides Phosphate group Sugar Figure 3.20A –composed of a sugar, phosphate, and nitrogenous base Nitrogenous base (A)

46. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings sugar and phosphate = backbone for nucleic acid Sugar-phosphate backbone Nucleotide Figure 3.20B

47. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings DNA is a nucleic acid, made of long chains of nucleotides DNA and RNA are polymers of nucleotides Figure 10.2A Nucleotide Phosphate group Nitrogenous base Sugar PolynucleotideSugar-phosphate backbone DNA nucleotide Phosphate group Nitrogenous base (A, G, C, or T) Thymine (T) Sugar (deoxyribose)

48. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings DNA = double helix – 2 polynucleotides Figure 3.20C Nitrogenous base (A) Base pair

49. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings DNA has four kinds of bases, A, T, C, and G Figure 10.2B Pyrimidines Thymine (T)Cytosine (C) Purines Adenine (A)Guanine (G)

50. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings RNA is also a nucleic acid –RNA has a slightly different sugar –RNA has U instead of T Figure 10.2C, D Phosphate group Nitrogenous base (A, G, C, or U) Uracil (U) Sugar (ribose)

51. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hydrogen bonds between bases hold the strands together –Each base pairs with a complementary partner –A pairs with T –G pairs with C

52. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings DNA vs RNA DNA RNA Double stranded Single Stranded A, T, C, G A, U, C, G Sugar = deoxyribose Sugar = ribose