Carbon and the Molecular Diversity of Life

1. Carbon and the Molecular Diversity of Life Chapter 4

2. The Backbone of Life • All living organisms are largely made up of chemicals that are based on elements of carbon • Other common ingredients include hydrogen, oxygen, nitrogen, sulfur, and phosphorous • The diversity of life is related to carbon and its ability to bond with other elements in a variety of ways

3. Organic Chemistry • All compounds containing carbon are said to be organic • Most also contain hydrogen • Be familiar with Miller’s experiment on page 59.

5. Carbon and Bonding • Carbon has 6 electrons which means only 4 are in the valance shell, leaving 4 “holes” to fill • Carbon generally shares its 4 carbon atoms via covalent bonds • In molecules, carbon can act as a hub where the molecule can branch off in as many as 4 directions (tetravalence).

6. Carbon and Molecular Diversity • Carbon skeletons vary in length • Skeletons may be branched or unbranched • The skeleton may have double bonds, which can vary in number and location • Some carbon skeletons are arranged in rings

7. Hydrocarbons • Consists only of carbon and hydrogen • Ex: Major component of petroleum • Not common alone in living organisms, but are common on regions of molecules • Ex: Fat has a hydrocarbon tail attached to a nonhydrocarbon component • Tend to be hydrophobic (because nonpolar) • Reactions tend to release large amounts of energy

8. Isomers • Compounds that have the same numbers of atoms of the same elements, but different structures and properties • Structural Isomers – differ in their covalent arrangement of atoms and may fiffer in the placement of their double bonds • Geometric Isomers – have the same covalent partnerships, but they differ in their spatial arrangements • Enantiomers – isomers that are mirror images of each other • Usually 1 is biologically active and the other is not • Ex: Thalidomide use in pregnant women • “good” version reduced morning sickness • “bad” version caused birth defects

9. Functional Groups • At times, a chemical group may replace one or more of the hydrogens bonded to the carbon skeleton. • These groups may participate in reactions and may play a role in the function of the molecule because of shape

10. Functional Groups 1)Hydroxyl • Hydrophilic; increases solubility

11. Functional Groups 2) Carbonyl • Hydrophilic; increases solubility • Know the difference between a ketone and an aldehyde

12. Functional Groups 3) Carboxyl • Hydrophilic; increases solubility

13. Functional Groups 4) Amino • Hydrophilic; increases solubility

14. Functional Groups 5) Sulfhydryl • Hydrophilic; increases solubility

15. Functional Groups 6) Phosphate • Hydrophilic; increases solubility

16. Functional Groups 7) Methyl • Non-Reactive • Acts as a recognizable tag on biological molecules

17. ATP • Adenosine Triphosphate • Organic molecule consists of an adenosine molecule attached to a string of 3 phosphate groups • A reaction with water causes the release of one of the phosphate groups also releasing energy. • Molecule becomes ADP