The Chemical Building Blocks of Life

1. The Chemical Building Blocks of Life Honors Biology Unit 2: Biochemistry Monkemeier

2. Organic Compounds • Organic compounds contain carbon and hydrogen and can exist as solids, liquids or gases. • Scientists coined the classification “organic” because these molecules were synthesized in living systems.

3. Arbitrary Classification System • Compounds that are considered organic (only made by organisms) have been synthesized in the lab. • Carbides, Carbonates, Oxides of Carbon (CO and CO2) and Cyanide are considered to be INORGANIC.

4. Versatility of Carbon • Carbon has four valence electrons. • To complete its valence shell, carbon forms four covalent bonds with other atoms. • The tetravalence of carbon is at the center of carbon’s ability to form large and complex molecules with characteristic three-dimensional shapes and properties.

5. Variation in Carbon Skeletons • Carbon atoms readily bond with each other, producing chains or rings of carbon atoms. • These molecular backbones can vary in length, branching, placement of double bonds, and location of atoms of other elements. The simplest molecules

6. Variation in Carbon Skeletons

7. Hydrocarbons • The simplest organic molecules are hydrocarbons consisting of only carbon and hydrogen. • The nonpolar C-H Bonds in hydrocarbon chains account for their hydrophobic behavior.

8. C – H Bonds and Energy

9. Think • When comparing the 4 categories of organic molecules (Carbohydrates, Lipids, Proteins and Nucleic Acids), Lipids contain the MOST C – H Bonds. • WHAT do you know about lipids as a result of the high number of C-H bonds?

10. Functional Groups • Functional groups are groups of atoms covalently bonded that when attached to organic molecules provide them with characteristic properties. • The functional groups studied in Chapter 4 are all HYDROPHILIC , therefore they INCREASE the solubility of the organic molecules in water.

11. Functional Groups • HYDROXYL: consists of an oxygen and hydrogen covalently bonded to the carbon skeleton. Organic compounds with hydroxyl groups are called ALCOHOLS and their names often end in –OL.

12. Carbonyl Groups • Carbonyl Groups consist of carbon double-bonded to an oxygen. If the carbonyl group is at the end of the carbon skeleton, the compound is called an aldehyde. Otherwise, the compound is called a ketone.

13. Carbonyl Groups

14. Carboxyl Group • Carboxyl groups consist of a carbon double-bonded to an oxygen and also attached to a hydroxyl group. Compounds with a carboxyl group are called carboxylic acids or organic acids because they tend to dissociate and release H+.

15. Carboxyl

16. Phosphate Group A phosphate group is bonded to the carbon skeleton its oxygen attached to the phosphorus atom that is bonded to three other oxygen atoms. The group is an anion.

17. Phosphate Group – Nucleic Acids

18. Amino Group • An amino group consists of a nitrogen atom bonded to two hydrogens. Compounds with an amino group, called amines, can act as bases. The nitrogen, with its pair of unshared electrons, can attract a hydrogen ion, becoming –NH3+

19. Amine Group – Amino Acids

20. Sulfhydryl Group • Sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom. Thiols are compounds containing sulfhydryl groups.

21. Sulfhydril

22. Identify the Functional Group

23. Isomers • Isomers are compounds with the same molecular formula but different structural arrangements and, thus, different properties.

24. Structural Isomers • Structural isomers differ in the arrangement of atoms and often in the location of double bonds.

25. Enantiomers(pronounced /ɨˈnæntɪ.ɵmər/ • Enantiomers are left-handed and right-handed versions of each other and can differ greatly in their biological activity. An asymmetric carbon is one that is covalently bonded to four-different kinds of atoms or groups of atoms. Due to the tetrahedral shape of the asymmetric carbon, the four groups can be attached in spatial arrangements that are not super-imposable on each other.

26. Enantiomers • Molecules that are optical isomers, or mirror images, of one another. Enantiomers can be distinguished by the direction in which they rotate the plane of polarization of polarized light and are referred to, therefore, as being dextrorotatory (D-) or laevorotatory (L-). Enantiomers can exist when there is an asymmetric carbon atom within the molecule

27. Optical Isomers

28. Geometric Isomers • Geometric isomers have the same sequence of covalently bonded atoms but differ in spatial arrangement due to the inflexibility of double bonds.

29. Geometric Isomers

30. The Chemical Elements of Life • Carbon, Hydrogen, Oxygen, Nitrogen, and smaller quantities of sulfur and phosphorus, all capable of forming strong covalent bonds, are combined into the complex organic molecules of living matter. • The versatility of carbon in forming four covalent bonds, linking readily with itself to produce chains and rings, and binding with other elements and functional groups makes possible the incredible diversity of organic molecules.