The Structure and Function of Macromolecules

1. The Structure and Function of Macromolecules Chapter 5

2. Molecules of Life • Another level of the hierarchy of biological organization is reached when small organic molecules are joined together • A polymer is a long molecule consisting of many similar building blocks called monomers

3. Classes of Macromolecules • Lipids • Carbohydrates • Proteins • DNA/RNA

4. Synthesis and Breakdown of Polymers • Enzymes: Used to make and breakdown polymers • Dehydration reaction (Condensation synthesis): Monomers combined by covalent bond and a water molecule is lost • Hydrolysis: To disassemble a polymer the water is added and the molecule separates.

6. Prefixes • Mono means 1 • Di means 2 • Tri means 3 • Poly means multiple

7. Carbohydrates (Saccharides) • Carbohydrates are sugars; many are polymers • Monosaccharides have the molecular formula CH2O or some multiple thereof Ex C6 H12 O6 • Disaccharides consist of two monomers joined by a glycosidic linkage • Storage Polysaccharides ; Starch in plants, glycogen in animals- more structurally branched • Structural Polysaccharides: Cellulose- major plant cell wall component

9. Monosaccharides shape • Exist in 2 forms • Linear • Circular • The two forms are interchangeable

10. Lipids • Lipids are more commonly known as fats • Lipids are non-polar molecules; they are not water soluble • They are hydrophobic • Lipids are important for energy storage • Fatty acids, Phospholipids, Steroids

11. Fatty acid chains can vary in • Length • Number of double bonds • Placement of the double bonds • Saturated fats have no double bonds • Solid at room temp • Unsaturated fats do have double bonds • Liquid at room temp

12. Phospholipids • Diglycerides with a phosphate group attached to glycerol backbone • Phosphate group is negatively charged • Fatty acid tails are non-polar and hydrophobic

13. Phospholipids • In aqueous enviroments, phospholipids spontaneously from aggregates • Hydrophobic tails are protected from the water. • Phospholipids are a major component in membranes

14. Steroids

15. Proteins • Proteins account for more than 50% of cell dry wt • Protein Functions • Structural • Contractile • Storage • Defense • Transport • Signaling • Catalysts

16. Proteins • Amino Acids are the building blocks of protein • There are 20 amino acids, 9 are essential = must eat them we cannot synthesize • phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, leucine, lysine, and histidine • Polypeptides are many amino acids joined together • The function of a protein depends on its chemical structure and unique 3-D shape

19. Making a polypeptide chain

20. Levels of Protein Structure • Primary Structure: Unique sequence of amino acids: sequence is determined by genetic material • Secondary Structure: coiling /folding as a result of hydrogen bonding • Tertiary Structure: 3-D shape due to bonding of R- groups and amino acids • Quaternary Structure: association of 2 or more polypeptides; Ex HGB ; not all have this level

25. Peptide Bonds between amino acids 2 Shapes R groups react: Hydrogen Bonds Disulfide Bridges Ionic bonds Hydrophobic Interactions Hydrogen Bonds Between carbon backbone Multiple polypeptides

28. Chaperons/Chaperonins • What levels of structure was being formed in the picture? • What predominantly holds these level together?

30. The “Blue Gene” Computer • IBM has a project • They hope to be able to take any amino acid sequence and produce a computer generation of the folded protein • Currently there are no computers powerful enough to do this

31. Denaturation • Denaturation means the protein structure is destroyed • Causes of denaturation include: • heat • pH • chemicals • Salt concentrations

32. Enzymes • Enzymes are proteins used to speed up chemical reactions = Catalysts • They are not consumed or converted in the reactions • In Ch 8 we will go into more detail

33. Nucleic Acids • Nucleic Acids carry information • Function is to store and transmit heritable information • DNA = carries all codes for life; double stranded • RNA = protein synthesis • Nucleotides/Nucleic Acids are composed of: • Nitrogenous Base:ATGC • Pentose = 5 Carbon sugar • Phosphate group • In DNA A pairs with T ; G with C

35. Nucleic Acids are the building blocks of protein • True • False

36. What macromolecule could be made from H, C, NH2,COOH, R • lipid • nucleic acid • carbohydrate • Amino acid

37. Checklist • What are the 4 macromolecules? What is the monomer, polymer and bonds that are found for each macromolecule? • Making polymers form monomers is called? • Breaking down polymers into monomers is? • What are the characteristics of fats? Saturated? Unsaturated? • What are the characteristics of carbohydrates?

38. Checklist • What part of the protein is involved in dehydration reactions? • What makes each protein unique? • What makes each amino acid unique? • What are nucleic acids? • What are enzymes? • What are the 4 levels of protein structure? What bonds are seen in each?