1. 3 Life and Chemistry: Large Molecules

2. 3 Theories of the Origin of Life Macromolecules: Giant Polymers Condensation and Hydrolysis Reactions Proteins: Polymers of Amino Acids Carbohydrates: Sugars and Sugar Polymers Lipids: Water-Insoluble Molecules Nucleic Acids: Informational Macromolecules That Can Be Catalytic All Life from Life

3. Figure 3.1 Synthesis of Prebiotic Molecules in an Experimental Atmosphere

4. 3 Macromolecules: Giant Polymers There are four major types of biological macromolecules:  Proteins  Carbohydrates  Lipids  Nucleic acids

5. 3 Macromolecules: Giant Polymers Macromolecules are giant polymers. Polymers are formed by covalent linkages of smaller units called monomers.

6. 3 Condensation and Hydrolysis Reactions Put together with CONDENSATION reactions  Forms an H 2 O molecule Broken apart by HYDROLYSIS (“Lysing” with water) reactions  Consumes an H 2 O molecule

7. Figure 3.3 Condensation and Hydrolysis of Polymers (Part 1)

8. Figure 3.3 Condensation and Hydrolysis of Polymers (Part 2)

9. 3 Proteins: Polymers of Amino Acids Proteins are polymers of amino acids. They are molecules with diverse structures and functions.

10. 3 Proteins: Polymers of Amino Acids Proteins are synthesized by condensation reactions between the amino group of one amino acid and the carboxyl group of another. This forms a peptide bond. “THE HYDROXYL OF THE CARBOXYL with the HYDROGEN OF THE AMINE”

11. Figure 3.5 Formation of Peptide Linkages

12. 3 Proteins: Polymers of Amino Acids There are four levels of protein structure: primary secondary tertiary and quaternary

13. Figure 3.11 Denaturation Is the Loss of Tertiary Protein Structure and Function

14. 3 Carbohydrates: Sugars and Sugar Polymers Carbohydrates are carbon molecules with hydrogen and hydroxyl groups. They act as energy storage and transport molecules. They also serve as structural components.

15. 3 Carbohydrates: Sugars and Sugar Polymers There are four major categories of carbohydrates:  Monosaccharides  Disaccharides, which consist of two monosaccharides  Oligosaccharides, which consist of between 3 and 20 monosaccharides  Polysaccharides, which are composed of hundreds to hundreds of thousands of monosaccharides

16. 3 Carbohydrates: Sugars and Sugar Polymers Polysaccharides are giant polymers of monosaccharides connected by glycosidic linkages. Cellulose is a giant polymer of glucose joined by  -1,4 linkages. Starch is a polysaccharide of glucose with  -1,4 linkages.

17. Figure 3.16 Representative Polysaccharides (Part 1)

18. Figure 3.17 Chemically Modified Carbohydrates (Part 4)

19. 3 Lipids: Water-Insoluble Molecules Lipids are insoluble in water. This insolubility results from the many nonpolar covalent bonds of hydrogen and carbon in lipids. Lipids aggregate away from water, which is polar, and are attracted to each other via weak, but additive, van der Waals forces.

20. 3 Lipids: Water-Insoluble Molecules Fats and oils store energy. Fats and oils are triglycerides, composed of three fatty acid molecules and one glycerol molecule. Glycerol is a three-carbon molecule with three hydroxyl (—OH) groups, one for each carbon. Fatty acids are long chains of hydrocarbons with a carboxyl group (—COOH) at one end.

21. Figure 3.18 Synthesis of a Triglyceride

22. Figure 3.19 Saturated and Unsaturated Fatty Acids

23. Figure 3.20 Phospholipid Structure

24. Figure 3.21 Phospholipids Form a Bilayer

25. 3 Lipids: Water-Insoluble Molecules Carotenoids are light-absorbing pigments found in plants and animals. One,  -carotene, is a plant pigment used to trap light in photosynthesis. In animals, this pigment, when broken into two identical pieces, becomes vitamin A.

26. Figure 3.22  –Carotene is the Source of Vitamin A

27. 3 Lipids: Water-Insoluble Molecules Steroids are signaling molecules. Steroids are organic compounds with a series of fused rings. The steroid cholesterol is a common part of animal cell membranes. Cholesterol is also is an initial substrate for synthesis of the hormones testosterone and estrogen.

28. Figure 3.23 All Steroids Have the Same Ring Structure

29. 3 Lipids: Water-Insoluble Molecules Some lipids are vitamins: small organic molecules essential to health. Vitamin A is important for normal development, maintenance of cells, and night vision. Vitamin D is important for absorption of calcium in the intestines. Vitamin E, an antioxidant, protects membranes. Vitamin K is a component required for normal blood clotting.

30. 3 Nucleic Acids: Informational Macromolecules That Can Be Catalytic Nucleic acids are polymers that are specialized for storage and transmission of information. Two types of nucleic acid are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). DNA encodes hereditary information and transfers information to RNA molecules. The information in RNA is decoded to specify the sequence of amino acids in proteins.

31. 3 Nucleic Acids: Informational Macromolecules That Can Be Catalytic Nucleic acids are polymers of nucleotides. A nucleotide consists of a pentose sugar, a phosphate group, and a nitrogen-containing base. In DNA, the pentose sugar is deoxyribose; in RNA it is ribose.

32. Figure 3.24 Nucleotides Have Three Components

33. Figure 3.28 Disproving the Spontaneous Generation of Life (Part 1)

34. Figure 3.28 Disproving the Spontaneous Generation of Life (Part 2)