BIOLOGICAL CHEMISTRY

Time to test your memory! Carbon Compounds *aka “organic compounds” *contain carbon (few exceptions like CO2) Time to test your memory! Question #1: How many valence electrons does C have? Question #2: How does this affect how C bonds?

Isomers: same chemical formula but have different structures Ex. C4H10 *B/C the structures are different, the properties are different!! MINI LAB DEMO: vinegar + different compounds If bubbles, CO2 released. CO2 contained here - carbonates QUESTION: Carbon dioxide is a major contributor to the greenhouse effect. What do you think would happen if organisms that produce carbonate compounds were to die off?

A. Carbohydrates *organic compound composed of C, H, O with the ratio of 2 H: 1 O *ex. Sugars, starch, glucose *Function: serve as energy sources *Simple Sugars: Monosaccharides Ex. Glucose C6H12O6 (in corn syrup) QUESTION: What do you think a disaccharide is? QUESTION: What do you think a polysaccharide is? Ex. Cellulose– used for support in plants

B. Lipids * organic compound composed of C, H, O but # of H much greater *ex. Fats, oils, waxes, cholesterol *Animals- produce solid fats Plants- produce liquid fats *Function: energy reserve; also part of cell membranes, provide insulation, and protect parts of nerves *Fat molecules are built by combo. of fatty acids and glycerol *All have carboxyl group (-COOH) *Saturated: single covalent bonds (“filled” with H) *Unsaturated: 1+ double covalent bond *QUESTION: Do you think lipids are insoluble or soluble in water?

C. Proteins *largest group of organic molecules *Function: building material like muscle, carry out chemical reactions, fight disease, transporting materials *Shape affects function! *Structure: C, H, O, N, S *Amino (NH2) group & carboxyl group *Amino Acids: building blocks of protein- 20 total *when amino acids (AA) bond together  peptide *polypeptide – many AA bonded together FYI: Aspartame– 2 AA’s: aspartic acid + phenylalanine

*Function: genetic code (DNA) carrying out instructions (RNA) D. Nucleic Acids *DNA and RNA Deoxyribonucleic acid and Ribonucleic acid *Most complex *Function: genetic code (DNA) carrying out instructions (RNA)

REACTIONS OF BIOLOGICAL COMPOUNDS QUESTION: C12H22O11 is made of 2 monosaccharides with the formula C6H12O6. Do you notice anything wrong with this? Condensation reaction: -OH broken from one molecule and –H from another  H2O is formed *small to larger molecules Hydrolysis reaction: Addition of water for reaction to take place; *large to smaller molecules *Important b/c complex substances simple in order to be processed by body (digestion)

ENZYMES *proteins that lower activation energy; allow reactions to occur at normal temperatures of cells *VERY SPECIFIC *Can be used over and over again *Shape affects reaction– usually 3D and globular *Reactants = substrates in cellular reactions *Enzymes named by adding –ase to name of substrate involved *Ex: rxn: maltose  glucose, the enzyme is “maltase”

  + QUESTION: Why are enzymes helpful? *Active site (part of enzyme’s surface) fits with substrate– lock and key model *More recently, “Induced Fit Model”: shapes don’t have to match perfectly b/c enzyme changes shape slightly like a flexible key EX: 2 AA  peptide: 2 AA’s   + + H20 enzyme enzyme peptide

*Enzymes sometimes require “helpers”: COENZYMES *Usually vitamin molecules or fragments *REUSABLE *Can join enzymes or transfer atoms from substrates Critical Thinking: To function properly, cells must carry out thousands of reactions and do so at appropriate times. How might the organization of cells be different if enzymes were not required for reactions?