Chapter 4: Carbon Do Now: How many bonds can carbon form?

Organic Compounds Compounds that contain carbon Most contain Hydrogen atoms as well as carbon. Why do we study carbon -- is it the most abundant element in living organisms? H & O most abundant C is the next most abundant

Carbon (The Backbone of life) Body consists of carbon based compounds (ex: proteins, lipids, carbohydrates, DNA) Carbon can form up to 4 bonds Most frequent partners are O, H, N Carbon chains form the skeleton of most organic molecules Why do we study carbon -- is it the most abundant element in living organisms? H & O most abundant C is the next most abundant

Hydrogen (valence = 1) Oxygen (valence = 2) Nitrogen (valence = 3) Fig. 4-4 Hydrogen (valence = 1) Oxygen (valence = 2) Nitrogen (valence = 3) Carbon (valence = 4) H O N C Figure 4.4 Valences of the major elements of organic molecules

Tetravalance Carbon can form 4 covalant bonds with a variety of atoms Why do we study carbon -- is it the most abundant element in living organisms? H & O most abundant C is the next most abundant

Tetrahedron In molecules with multiple carbons, each carbon bonded to four other atoms has a tetrahedral shape When 2 carbons are joined by a double bond, the molecules is flat in shape Why do we study carbon -- is it the most abundant element in living organisms? H & O most abundant C is the next most abundant

Hydrocarbons Organic molecules consisting of only carbon and hydrogen Non-polar molecules (fats) Why do we study carbon -- is it the most abundant element in living organisms? H & O most abundant C is the next most abundant

Carbon Skeletons Why do we study carbon -- is it the most abundant element in living organisms? H & O most abundant C is the next most abundant

Isomers Molecules with same molecular formula but different structures (shapes) different chemical properties different biological functions Same formula but different structurally & therefore different functionally. Molecular shape determines biological properties. Ex. Isomers may be ineffective as medicines 6 carbons 6 carbons 6 carbons

Structural: different covalent arrangement Fig. 4-7 Structural: different covalent arrangement Pentane 2-methyl butane (a) Structural isomers Geometric: same covalent arrangements, different spatial arrangements cis isomer: The two Xs are on the same side. trans isomer: The two Xs are on opposite sides. (b) Geometric isomers Figure 4.7 Three types of isomers Enantiomers: isomers that are mirror images L isomer D isomer (c) Enantiomers

Isomers- Form affects function Structural differences create important functional significance medicines L-version active but not D-version sometimes with tragic results…

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

Effective Enantiomer Ineffective Enantiomer Drug Condition Pain; Fig. 4-8 Effective Enantiomer Ineffective Enantiomer Drug Condition Pain; inflammation Ibuprofen S-Ibuprofen R-Ibuprofen Figure 4.8 The pharmacological importance of enantiomers Albuterol Asthma R-Albuterol S-Albuterol

Functional groups Parts of organic molecules that are involved in chemical reactions give organic molecules distinctive properties  hydroxyl  amino  carbonyl  sulfhydryl  carboxyl  phosphate Affect reactivity makes hydrocarbons hydrophilic increase solubility in water

Hydroxyl –OH organic compounds with OH = alcohols names typically end in -ol ethanol

Carbonyl C=O O double bonded to C if C=O at end molecule = aldehyde if C=O in middle of molecule = ketone

Carboxyl –COOH C double bonded to O & single bonded to OH group compounds with COOH = acids fatty acids amino acids

Amino -NH2 N attached to 2 H compounds with NH2 = amines amino acids NH2 acts as base ammonia picks up H+ from solution

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

Phosphate –PO4 P bound to 4 O connects to C through an O lots of O = lots of negative charge highly reactive transfers energy between organic molecules ATP

Look at the difference Basic structure of male & female hormones is identical identical carbon skeleton attachment of different functional groups interact with different targets in the body different effects For example the male and female hormones, testosterone and estradiol, differ from each other only by the attachment of different functional groups to an identical carbon skeleton.

Diversity of molecules Substitute other atoms or groups around the carbon ethane vs. ethanol H replaced by an hydroxyl group (–OH) nonpolar vs. polar gas vs. liquid biological effects! ethane (C2H6) ethanol (C2H5OH)