1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 3 Lecture Slides

2. 3.1 Polymers Are Built of Monomers Organic molecules make up the bodies of living organisms  have a carbon-based core  the core has attached groups of atoms called functional groups the functional groups confer specific chemical properties on the organic molecules

3. Figure 3.2 Five principal functional groups

4. 3.1 Polymers Are Built of Monomers The building materials of the body are known as macromolecules because they can be very large There are four types of macromolecules: 1.Proteins 2.Nucleic acids 3.Carbohydrates 4.Lipids Macromolecules are actually assembled from many similar small components, called monomers  the assembled chain of monomers is known as a polymer

5. 3.1 Polymers Are Built of Monomers All macromolecules are assembled the same way  a covalent bond is formed between two subunits by removing a hydroxyl group (OH) from one subunit and a hydrogen (H) from another subunit  because this amounts to the removal of a molecule of water (H 2 O), this process is called dehydration synthesis

6. Figure 3.4(a) Dehydration synthesis

7. 3.1 Polymers Are Built of Monomers The process of disassembling polymers into component monomers is essentially the reverse of dehydration synthesis  a molecule of water is added to break the covalent bond between the monomers  this process is known as hydrolysis

8. Figure 3.4(b) Hydrolysis

9. 3.2 Proteins Proteins are complex macromolecules that are polymers of many subunits called amino acids Figure 3.3(a) Polymers are built of monomers: protein

10. 3.2 Proteins Amino acids are small molecules with a simple basic structure, a carbon atom to which three groups are added an amino group (-NH 2 ) a carboxyl group (-COOH) a functional group (R) The functional group gives amino acids their chemical identity  there are 20 different types of amino acids

11. Figure 3.6 Basic structure of an amino acid

12. Animation: Limiting Amino Acids Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.

13. 3.2 Proteins The covalent bond linking two amino acids together is called a peptide bond The assembled polymer is called a polypeptide

14. Figure 3.7 The formation of the peptide bond

15. 3.2 Proteins Protein structure is complex  the order of the amino acids that form the polypeptide affects how the protein folds together  the way that a polypeptide folds to form the protein determines the protein’s function some proteins are comprised of more than one polypeptide

16. 3.2 Proteins There are four general levels of protein structure 1.Primary structure 2.Secondary structure 3.Tertiary structure 4.Quaternary structure

17. 3.2 Proteins Primary structure – the sequence of amino acids in the polypeptide chain This determines all other levels of protein structure Figure 3.8 Levels of protein structure: primary structure

18. 3.2 Proteins Secondary structure – the initial folding of the amino acid chains Occurs because regions of the polypeptide that are non- polar are forced together The folded structure may resemble coils, helices, or sheets Figure 3.8 Levels of protein structure: secondary structure

19. 3.2 Proteins Tertiary structure – the final 3-D shape of the protein The final twists and folds that lead to this shape are the result of polarity differences in regions of the polypeptide Figure 3.8 Levels of protein structure: tertiary structure

20. 3.2 Proteins Quaternary structure – the spatial arrangement of component polypeptides in proteins comprised of more than one polypeptide chain Figure 3.8 Levels of protein structure: quaternary structure

21. 4.2 Protein Changes to the environment of the protein may cause it to unfold or denature  increased temperature or lower pH affects hydrogen bonding, which is involved in the folding process  a denatured protein is inactive

22. Figure 3.9 Protein denaturation

23. Animation: Protein Denaturation Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.

24. 4.2 Proteins The shape of a protein affects its function  proteins that serve architectural and structural roles are often long and cable-like  Proteins that act as enzymes are globular, having a special 3-D shape that fits precisely with another chemical they cause the chemical that they fit with to undergo a reaction

25. Figure 3.10 Protein structure determines function

26. 3.3 Nucleic Acids Nucleic acids are very long polymers that store information  comprised of monomers called nucleotides Figure 3.3(b) Polymers are built of monomers: nucleic acid

27. 3.3 Nucleic Acids Each nucleotide has 3 parts 1.a five-carbon sugar 2.a phosphate group 3.an organic nitrogen-containing base  there are five different types of nucleotides information is encoded in the nucleic acid by different sequences of these nucleotides

28. Figure 3.11 The structure of a nucleotide

29. 3.3 Nucleic Acids There are two types of nucleic acids  Deoxyribonucleic acid (DNA)  Ribonucleic acid (RNA) RNA is similar to DNA except that  it uses uracil instead of thymine  it is comprised of just one strand  it has a ribose sugar

30. Figure 3.12 How DNA structure differs from RNA

31. 3.3 Nucleic Acids The structure of DNA is a double helix because  there are only two base pairs possible Adenine (A) pairs with thymine (T) Cytosine (C) pairs with Guanine (G)  the bonds holding together a base pair are hydrogen bonds  a sugar-phosphate backbone comprised of phosphodiester bonds gives support

32. Figure 3.13 The DNA double helix

33. 3.3 Nucleic Acids The structure of DNA helps it to function  the hydrogen bonds of the base pairs can be broken to unzip the DNA so that information can be copied each strand of DNA is a mirror image so the DNA contains two copies of the information  having two copies means that the information can be accurately copied and passed to the next generation

34. 3.4 Carbohydrates Carbohydrates are used for energy or sometimes as structural molecules  a carbohydrate is any molecule that contains the elements C, H, and O in a 1:2:1 ratio  the sizes of carbohydrates varies simple carbohydrates – made up of one or two monomers complex carbohydrates – long polymers Figure 3.3(c) Polymers are built of monomers: carbohydrate

35. 3.4 Carbohydrates Simple carbohydrates are small  monosaccharides consist of only one monomer subunit an example is the sugar glucose (C 6 H 12 O 6 )  disaccharides consist of two monosaccharides an example is the sugar sucrose, which is formed by joining together two monosaccharides, glucose and fructose

36. Figure 3.14 The structure of glucose

37. 3.4 Carbohydrates Complex carbohydrates are long polymer chains  because they contain many C-H bonds, these carbohydrates are good for storing energy these bond types are the ones most often broken by organisms to obtain energy  the long chains are called polysaccharides

38. 3.4 Carbohydrates Plants and animals store energy in polysaccharide chains formed from glucose  plants form starch  animals form glycogen Some polysaccharides serve structural functions and are resistant to digestion by enzymes  cellulose is found in the cell walls of plants  chitin is found in the exoskeletons of many invertebrates and in the cell walls of fungi

39. Table 3.1 Carbohydrates and their functions

40. 3.5 Lipids Lipids – fats and other molecules that are not soluble in water  lipids are nonpolar molecules  lipids include fats, phospholipids, and many other molecules Figure 3.3(d) Polymers are built of monomers: lipid

41. 3.5 Lipids Fats are used for long-term energy storage  fats have two subunits 1.fatty acids 2.glycerol  fatty acids are chains of C and H atoms  Glycerol contains three carbons and forms the backbone to which three fatty acids are attached

42. Animation: Energy Sources for Prolonged Exercise Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.

43. 3.5 Lipids Fatty acids have different chemical properties due to the number of hydrogens that are attached to chain of carbons  if the maximum number of hydrogens are attached, then the fat is said to be saturated  if there are fewer than the maximum attached, then the fat is said to be unsaturated

44. Figure 3.17 Saturated and unsaturated fats

45. 3.5 Lipids Biological membranes involve lipids  phospholipids make up the two layers of the membrane  cholesterol (a steroid) is embedded within the membrane Lipids also include oils, other steroids, rubber, waxes, and pigments Figure 3.16 Lipids are a key component of biological membranes

46. Inquiry & Analysis Which of the three pH values represents the highest concentration of hydrogen ions? How does pH affect the release of oxygen from hemoglobin? How Does pH Affect a Protein’s Function?