AP Biology Objective: SWBAT explain the role of carbon in the molecular diversity of life and identify the functional groups that determine the properties of organic compounds 1. Briefly explain how Water Striders (“Jesus bugs”) are able to walk on water using the properties of water learned last class 1. Which of the following is a correct statement about the relationship between pH and the hydrogen-ion concentration of a solution? A. There are no hydrogen ions present in a solution with a basic pH. B. There are no hydrogen ions present in a solution with a neutral pH of 7.0. C. The concentration of hydrogen ions in a solution with a pH of 7.0 is 100 times as great as that in a solution with a pH of 9.0. D. The concentration of hydrogen ions in a solution with a pH of 5.0 is twice that in a solution with a pH of 3.0. E. The concentration of hydrogen ions in a solution with a pH of 4.0 is 400 times as great as that in a solution with a pH of 1.0.

AP Biology ANNOUNCEMENTS  Look over Carbon Compounds and function groups  Mini quiz tomorrow morning

AP Biology Unit 1: Chemistry of Life Chapter 3 – Introduction to Organic Compounds

AP Biology Why study Carbon?  All living things are made of cells  Cells  ~70-95% water, the rest consists of carbon compounds  carbohydrates  lipids  proteins  nucleic acids

AP Biology Chemistry of Life  Organic chemistry is the study of carbon compounds  C atoms are versatile building blocks  bonding properties  4 stable covalent bonds

AP Biology  The electron configuration of carbon gives it compatibility to form covalent bonds with many different elements. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 4.3

AP Biology Complex molecules assembled like TinkerToys

AP Biology Hydrocarbons  Simplest C molecules = hydrocarbons  combinations of carbon atoms attached to hydrogens  Simplest HC molecule = methane  1 carbon bound to 4 H atoms  non-polar  not soluble in H 2 O  hydrophobic  stable  very little attraction between molecules  a gas at room temperature

AP Biology Hydrocarbons can grow (Carbon Skeleton)  adding C-C bonds  straight line  ethane  hexane  branching  isohexane  ring  cyclohexane ethane hexane cyclohexane isohexane methane

AP Biology Variation in carbon skeletons contributes to the diversity of organic molecules Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

AP Biology Diversity of organic molecules

AP Biology Isomers  Molecules with same molecular formula but different structures  different chemical properties

AP Biology Structural isomers  Molecules differ in structural arrangement of atoms

AP Biology Geometric isomers  Molecules differ in arrangement around C=C double bond  same covalent partnerships

AP Biology Enantiomer (stereo) isomers  Molecules which are mirror images of each other  C bonded to 4 different atoms or groups  assymetric  left-handed & right-handed versions

AP Biology Form affects function  Structural differences create important functional significance  amino acid alanine  L-alanine used in proteins  but not D-alanine  medicines  L-version active  but not D-version  sometimes with tragic results…

AP Biology Form affects function  Thalidomide  prescribed to pregnant women in 50’s & 60’s  reduced morning sickness, but…  stereoisomer caused severe birth defects

AP Biology Functional Groups

AP Biology Functional groups  Components of organic molecules that are involved in chemical reactions  give organic molecules distinctive properties  ex: male & female hormones…

AP Biology Viva la difference!  Basic structure of male & female hormones is identical  identical C skeleton  attachment of DIFFERENT FUNCTIONAL GROUPS  interact with different targets in the body

AP Biology Types of functional groups  6 functional groups most important to chemistry of life:  hydroxyl u amino  carbonyl u sulfhydryl  carboxyl u phosphate  Affect reactivity  hydrophilic  increase solubility in water

AP Biology Hydroxyl  –OH  organic compounds with OH = alcohols  names typically end in -ol  ethanol

AP Biology Carbonyl  C=O  O double bonded to C  if C=O at end molecule = aldelhyde  if C=O in middle of molecule = ketone

AP Biology Carboxyl  –COOH  C double bonded to O & single bonded to OH group  compounds with COOH = acids  fatty acids  amino acids

AP Biology Amino  -NH 2  N attached to 2 H  compounds with NH 2 = amines  amnio acids  NH 2 acts as base  ammonia picks up H + from solution

AP Biology Sulfhydryl  –SH  S bonded to H  compounds with SH = thiols  SH groups stabilize the structure of proteins

AP Biology Phosphate  –PO 4  P bound to 4 O  connects to C through an O  PO 4 are anions with 2 negative charges  function of PO 4 is to transfer energy between organic molecules (ATP)

AP Biology Why study Functional Groups?  These are the building blocks for biological molecules …and that comes next!

AP Biology  Living matter consists mainly of carbon, oxygen, hydrogen, and nitrogen, with smaller amounts of sulfur and phosphorus.  These elements are linked by strong covalent bonds.  Carbon with its four covalent bonds is the basic building block in molecular architecture.  The great diversity of organic molecules with their special properties emerge from the unique arrangement of the carbon skeleton and the functional groups attached to the skeleton. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

AP Biology Any Questions??