1. What is the chemical basis of life? What are some of the ideas central to the chemistry of life? (Key concepts of the chemical basis of life)

2. Ideas central to the chem of life Based on covalent bonding Carbon is the “backbone” of biomolecules Simple building code Variation on common theme in extreme Only 4 fundamental types of biomolecules Enzymes make and break the covalent bonds in the chemical reactions in the cell Isomers and polymers Condensation and Hydrolysis

3. Elements Essential to Life About 25 of the 92 natural occurring elements are essential to life CHON = 96% liv mat CHONPS = > 99%

4. Famous ions in Biology Hydronium H 3 O + and Hydroxide OH - Potassium K + ions Sodium Na + ions Calcium Ca 2+ ions Hydrogen H + ions (protons)

5. A continuum view of bonding Atoms complete their valence shell in a continuum of: Nonpolar covalent with equal sharing of e- –Examples: H—H O = O Polar covalent, unequal sharing of e- –Examples: H 2 O NH 3 Ionic, with complete transfer of e- –Examples: NaCl Al 2 O 3

6. Weak Bonds are Bio’ly Important H bonds, hydrophobic interactions Can form between different parts of a single large molecule or between molecules Help stabilize 3D shape of proteins & Nucleic Acids Hold enzymes to substrates Function in chemical signaling

7. Biological Building Codes Covalent Bond= shared pair of electrons between 2 nonmetals H, 1 unpaired e- O, 2 unpaired e- N, 3 unpaired e- C, 4 unpaired e-

8. Versatility of Carbon 4 valence electrons Compatibility with many different el’s S, D, T bonds Makes large, complex molecules possible –Strait chains –Branched chains –Rings

9. Polymer (poly = many; mer = part) Large molecules consisting of many similar subunits connected together Monomer = subunit or building block of polymer

10. Macromolecules are Polymers Carbohydrates = polymer of monosaccharides Lipids = polymer of fatty acids & glycerol Proteins = polymer of amino acids Nucleic Acids = polymer of nucleotides

11. Polymers & Molecular Diversity Unity in life: Only about 40 or 50 common monomers build macromolecules Diversity in life: New properties emerge when these monomers are arranged in different ways

12. Sucrose Synthesis

13. Hydrolysis

14. Making & Breaking Polymers animation animation Dehydration synthesis Link monomers Via removal of H 2 O 1 water per link (out) One monomer lose OH, other loses H Any assembling of molecules in cells Hydrolysis Disassemble polymers Via addition of H 2 O 1 water per link (in) One monomer gains OH, other gains H Any disassembly of molecules in cells

15. Carbohydrates (sugars) Classified based on # of simple sugars C H O in 1:2:1 ratio Major nutrients for cells; ie glucose Produced by photosynthetic organisms Store energy in chemical bonds C skeletons raw materials for other organic compounds

16. Carbohydrates-disaccharides Disacch.Monomers Maltoseglu + glu Lactoseglu + galac Sucroseglu + fru

17. Carbohydrates: Polysaccharides 2 Important biological functions: –Energy storage (starch, glycogen) –Structural support (cellulose, chitin)

18. Storage Polysaccharides Starch = glucose polymer, for energy storage in plants –Helical glucose polymer –Most animals have enzymes to hydrolyze it –Major sources in Human diet are potatoes And grains

19. Storage Polysaccharides Glycogen = glucose polymer, for energy storage in animals Branched molec. Stored in muscle and liver of humans and other vertebrates

20. Structural Polysaccharides Cellulose = linear unbranched polymer –Major structural component of plant cell walls –Differs from starch in its monomer linkage –Cannot be digested by most organisms

21. Structural Polysaccharides Chitin = structural polysacch.; a polymer of an amino sugar (nature’s plastic) Forms exoskeleton of Arthropods Found as cell walls in fungi

22. Lipids Diverse group of organic compounds that are insoluble in water Includes animal fats, plant oils, steroids, phospholipids Made of fatty acids and glycerol

23. Fat Saturated All single bonds Solid at room temp Animal fats Unsaturated One or more double bonds between carbons Liquid at room temp “Vegetable” or plant oils

24. Useful functions of fat Energy storage More compact fuel reserve than carbo. Cushions vital organs in mammals Insulates against heat loss

25. Phospholipids Component of cell membranes (bilayer) 2 fatty acids & phosphate group Amphipathic behavior in water

26. Steroids Lipids w/ 4 fused carbon rings and various functional groups Cholesterol important as precurser to other steroids; and enhance membrane fluidity

27. Proteins Complex polymers of amino acids Abundant: make up 50% or more of dry wt Varied functions in cell: structure, metabolism, transport, signaling, movement, defense Each has unique 3-D shape Made of only 20 different amino acids

28. Amino Acid Structure

29. Nucleic Acids Deoxyribonucleic Acid (DNA) Can replicate itself and be passed from one generation of cells to the next Genes are segments of DNA that code for protein Ribonucleic Acid (RNA) Functions as mediator between genotype and phenotype 3 functional forms carry out “protein synthesis”

30. Nucleic Acids DNA, the Genetic CodeRNA the Trait Maker

31. Nucleotides: monomers of nucleic acids Pentose, a 5C sugar Nitrogen Base Phosphate