1. Functional groups Play pivotal role in chemical & physical properties of organic molecules.Play pivotal role in chemical & physical properties of organic molecules. Compounds that are made up solely of carbon and hydrogen are not very reactive.Compounds that are made up solely of carbon and hydrogen are not very reactive. Functional groups:Functional groups: One or more H atoms of the carbon skeleton may be replaced by a functional group. Groups of atoms that have unique chemical and physical properties. Usually a part of molecule that is chemically active. Similar activity from one molecule to another. Together with size and shape, determine unique bonding and chemical activity of organic molecules.

2. Structural Polysaccharides: Used as structural components of cells and tissues. Used as structural components of cells and tissues. 1. Cellulose: Glucose polymer. The major component of plant cell walls. CANNOT be digested by animal enzymes. Only microbes have enzymes to hydrolyze. 2. Chitin: Polymer of an amino sugar (with NH 2 group) Forms exoskeleton of arthropods (insects) Found in cell walls of some fungi

3. Cellulose: Polysaccharide Found in Plant and Algae Cell Walls

4. Proteins: Large three-dimensional macromolecules responsible for most cellular functionsLarge three-dimensional macromolecules responsible for most cellular functions Polypeptide chains: Polymers of amino acids linked by peptide bonds in a SPECIFIC linear sequence Protein: Macromolecule composed of one or more polypeptide chains folded into SPECIFIC 3-D conformations

5. Polypeptide: Polymer of amino acids connected in a specific sequence Amino acid Structure: Central carbon with: H atom Carboxyl group Amino group Variable R-group Amino Acid Structure: H | | (Amino Group) NH 2 ---C---COOH (Carboxyl group) | | R (Varies for each amino acid)

6. Amino Acids Have Both -NH 2 and -COOH Groups

7. Proteins have important and varied functions: 1.Enzymes: Catalysis of cellular reactions 2. Structural Proteins: Maintain cell shape 3. Transport: Transport in cells/bodies (e.g. hemoglobin). Channels and carriers across cell membrane. 4. Communication: Chemical messengers, hormones, and receptors. 5. Defensive: Antibodies and other molecules that bind to foreign molecules and help destroy them. 6. Contractile: Muscular movement. 7. Storage: Store amino acids for later use (e.g. egg white). Protein function is dependent upon its 3-D shape.

8. Protein Function is dependent upon Protein Structure (Conformation) CONFORMATION: The 3-D shape of a protein is determined by its amino acid sequence. Four Levels of Protein Structure 1. Primary structure: Linear amino acid sequence, determined by gene for that protein. 2. Secondary structure: Regular coiling/folding of polypeptide. Alpha helix or beta sheet. Alpha helix or beta sheet. Caused by H-bonds between amino acids. Caused by H-bonds between amino acids. 3. Tertiary structure: Overall 3-D shape of a polypeptide chain. 4. Quaternary structure: Only in proteins with 2 or more polypeptides. Overall 3-D shape of all chains. Example: Hemoglobin (2 alpha and 2 beta polypeptides)

10. Primary Structure of Protein: Amino Acid Sequence is Determined by Gene

11. Secondary Structure of Protein: Regular Folding Patterns (Alpha Helix or Pleated Sheet)

12. Protein Shape is determined by bonding between elements of different amino acids. There are 4 types of bonds that occur in proteins: 1. Ionic bond 2. Disulphide bond 3. Hydrogen 4. Hydrophobic interactions Due to the functional groups attached to amino acids

13. Tertiary Structure: Overall 3-D Shape of Protein Tertiary Structure of Lysozyme

14. Quaternary Structure: Overall 3-D Shape of Protein with 2 or More Subunits

15. What determines a protein’s shape? A. Primary structure: Exact location of each amino acid along the chain determines the protein’s folding pattern. Example: Sickle Cell Hemoglobin protein Mutation changes amino acid #6 on the alpha chain. Defective hemoglobin causes red blood cells to assume sickle shape, which damages tissue and capillaries. Sickle cell anemia gene is carried in 10% of African Americans.

16. What determines a protein’s shape? B. Chemical & Physical Environment: Presence of other compounds, pH, temperature, salts. –Denaturation: Process which alters native conformation and therefore biological activity of a protein. Several factors can denature proteins: 1.pH and salts: Disrupt hydrogen, ionic bonds. 2.Temperature: Can disrupt weak interactions. Example: Function of an enzyme depends on pH, temperature, and salt concentration.

17. Nucleic acids Nucleic acids Store and transmit hereditary information for all living things There are two types of nucleic acids in living things: A. Deoxyribonucleic Acid (DNA) Contains genetic information of all living organisms. Has segments called genes which provide information to make each and every protein in a cell Double-stranded molecule which replicates each time a cell divides. B. Ribonucleic Acid (RNA) Three main types called mRNA, tRNA, rRNA RNA molecules are copied from DNA and used to make gene products (proteins). Usually exists in single-stranded form.

18. DNA and RNA are polymers of nucleotides that determine the primary structure of proteins Nucleotide: Subunits of DNA or RNA. Nucleotides have three components: 1. Pentose sugar (ribose or deoxyribose) 2. Phosphate group to link nucleotides (-PO 4 ) 3. Nitrogenous base (A,G,C,T or U) Purines: Have 2 rings. Adenine (A) and guanine (G) Pyrimidines: Have one ring. Cytosine (C), thymine (T) in DNA or uracil (U) in RNA.

20. James Watson and Francis Crick Determined the 3- D Shape of DNA in 1953 Double helix: The DNA molecule is a double helix. Antiparallel: The two DNA strands run in opposite directions. Strand 1: 5’ to 3’ direction (------------>) Strand 2: 3’ to 5’ direction (<------------) Complementary Base Pairing: A & T (U) and G & C. A on one strand hydrogen bonds to T (or U in RNA). G on one strand hydrogen bonds to C. Replication: The double-stranded DNA molecule can easily replicate based on A=T and G=C pairing. --- --- SEQUENCE of nucleotides in a DNA molecule dictate the amino acid SEQUENCE of polypeptides

21. DNA: Double Helix of Two Complementary Strands Held Together by H-Bonds

22. A Gene A specific segment of a DNA molecule with information for cell to make one polypeptide.A specific segment of a DNA molecule with information for cell to make one polypeptide. DNA (transcribed into single stranded RNA “copy”) mRNA(single stranded “copy” of the gene) Polypeptide (mRNA message translated into polypeptide)

23. Genetic Information Flow: DNA to RNA to Protein

24. Lipids: Fats, phospholipids, and steroids Diverse groups of compounds. Composition of Lipids: C, H, and small amounts of O. Functions of Lipids: Biological fuels Energy storage Insulation Structural components of cell membranes Hormones

25. Lipids: Fats, phospholipids, and steroids 1. Simple Lipids: Contain C, H, and O only. A. Fats (Triglycerides). Glycerol : Three carbon molecule with three hydroxyls. Fatty Acids: Carboxyl group and long hydrocarbon chains. Characteristics of fats: Most abundant lipids in living organisms. Hydrophobic (insoluble in water) because nonpolar. Economical form of energy storage (provide 2X the energy/weight than carbohydrates). Greasy or oily appearance.

26. Fats (Triglycerides): Glycerol + 3 Fatty Acids

27. Lipids: Fats, phospholipids, and steroids Types of Fats Saturated fats: Hydrocarbons saturated with H. Lack -C=C- double bonds. Solid at room temp (butter, animal fat, lard) Unsaturated fats: Contain -C=C- double bonds. Usually liquid at room temp (corn, peanut, olive oils)

28. Saturated Fats Contain Saturated Fatty Acids

29. Complex Lipids: Phospholipids In addition to C, H, and O, also contain other elements, such as phosphorus, nitrogen, and sulfur. A. Phospholipids: Are composed of: Glycerol 2 fatty acid Phosphate group Amphipathic Molecule Hydrophobic fatty acid “tails”. Hydrophilic phosphate “head”. Function:Primary component of the plasma membrane of cells Function: Primary component of the plasma membrane of cells

30. Phospholipids: Amphipathic Molecules

31. In Water Phospholipids Spontaneously Assemble into Organized Structures

32. Steroids: Lipids with four fused carbon rings 1. Includes cholesterol, bile salts, reproductive, and adrenal hormones. Cholesterol: The basic steroid found in animals Common component of animal cell membranes.Common component of animal cell membranes. Precursor to make sex hormones (estrogen, testosterone)Precursor to make sex hormones (estrogen, testosterone) Generally only soluble in other fats (not in water)Generally only soluble in other fats (not in water) Too much increases chance of atherosclerosis.Too much increases chance of atherosclerosis. Waxes: One fatty acid linked to an alcohol. Very hydrophobic. Very hydrophobic. Found in cell walls of certain bacteria, plant and insect coats. Help prevent water loss. Found in cell walls of certain bacteria, plant and insect coats. Help prevent water loss.