Building Blocks of Life

1. Building Blocks of Life An Introduction

2. Carbon is unparalleled in its ability to form large, complex, and diverse molecules • Proteins, DNA, carbohydrates, and other molecules that distinguish living matter are all composed of carbon compounds Carbon—The Backbone of Biological Molecules

3. Electron configuration determines the kinds and number of bonds an atom will form with other atoms • With four valence electrons, carbon can form four covalent bonds with a variety of atoms • makes large, complex molecules possible Carbon atoms can form diverse molecules by bonding to four other atoms

4. The valences of carbon and its most frequent partners (hydrogen, oxygen, and nitrogen) are the “building code” that governs the architecture of living molecules

5. Within cells, small organic molecules are joined together to form larger molecules • Macromolecules are large molecules composed of thousands of covalently connected atoms Macromolecules

6. Monomers build polymers linked together by covalent bonds • Three of the four classes of life’s organic molecules are polymers: • Carbohydrates • Proteins • Nucleic acids • Lipids polymers built from monomers

7. Monomers form larger molecules by condensation reactions called dehydration reactions • Polymers are disassembled to monomers by hydrolysis, a reaction that is essentially the reverse of the dehydration reaction The Synthesis and Breakdown of Polymers

8. Short polymer Unlinked monomer Dehydration removes a water molecule, forming a new bond Longer polymer Dehydration reaction in the synthesis of a polymer Hydrolysis adds a water molecule, breaking a bond Hydrolysis of a polymer

9. Sugars and sugar polymers • Monosaccharides • Simple sugars • glucose Carbonyl group Hydroxyl group Carbohydrates

10. Disaccharides • 2 or more monosaccharides joined by glycosidic linkage, covalent bond by dehydration reaction • Glucose + fructose sucrose Carbohydrates

11. Storage • Plant starch • Stored energy can be broken down by hydrolysis into glucose • Animal polysaccharide • Glycogen • Stored in liver and muscles • Used for short term energy Carbohydrates

12. Structure • Cellulose: cell walls • Requires an enzyme for animals to break it down • Chitin: exoskeleton of arthropods and fungi Carbohydrates

13. Fats, oils, waxes • Mix poorly with water • Fats • Large molecules of glycerol and fatty acid chains connected by dehydration Lipids

14. Cell Membranes • Phospholipid bi-layer Lipids

15. Polymer of amino acids called polypeptides • Functions • Enzymes • Storage of amino acids • Hormones • Motor • Defense • Transport • Receptors for chemical stimuli • structure Proteins

16. Amino acids • 20 amino acids from 1000’s of proteins • Side chains “R” determines the properties • Hydrophillic:polar • Hydrophobic: non polar • Hydrophillic: electric charge Proteins

17. Structure • 1° • Linear chain Proteins

18. 2° • Alpha helix: hair • β pleated sheets: spider web • Held together by hydrogen bonds between amino groups Proteins

19. 3° • Interactions between side chains “R” • Hydrogen bonds • Ionic bonds • Disulfide bonds • Van der Waals Proteins

20. 4° • Aggregation of polypeptide subunits • Collagen • hemoglobin Proteins

21. Denaturation • Weak chemical bonds and interactions can be destroyed • Heat • pH Proteins

22. Polymer of nucleotides • DNA and RNA Nucleic Acids