Molecules of Life

1. Molecules of Life Compounds that contain carbon What are biological molecules? What are organic molecules? Nucleic Acids Carbohydrates Lipids Proteins

2. Organic Molecules What is a cell made up of mostly? Mostly water, but what else? Carbon based molecules Why is carbon so significant for these molecules?

3. Each carbon acts as an ‘intersection’ With 4 different branch points Creates endless variety of (organic) carbon molecules Vary in length

4. Diversity of Carbon-Based Molecules Different location of double bonds Unbranched or branched Rings

5. Methane What is a hydrocarbon? Is a hydrocarbon ……….. Carbon & Hydrogen Methane is the simplest

6. Functional Groups • Groups of atoms known as functional groups can give special properties on carbon-based molecules. • Carbon is a central element to life because most biological molecules are built on a carbon framework.

7. Functional Groups • For example, the addition of an –OH group to a hydrocarbon molecule always results in the formation of an alcohol.

8. Functional Groups

9. Making Polymers Dehydration* Reaction - links molecules together • A covalent bond forms between molecules and water is removed • Reaction by which monomers are joined to form larger molecules • Examples: • *Also called a condensation reaction

11. Breaking Polymers Hydrolysis reaction – breaks down larger molecules • Water is added to a larger molecule to split off a smaller molecule. • Reaction involves breaking a covalent bond by adding water • Reverse of a dehydration reaction

13. Biological Molecules Food ‘Carbs’ Structural Sugar Storage Glucose Enzymes Glycogen Antibodies Cellulose Oils Fatty acids (sat & unsat) DNA RNA Butter

14. Carbohydrates • Carbohydrates are formed from the building blocks or monomers of simple sugars, such as glucose. • These monomers can be linked to form larger carbohydrate polymers, which are known as polysaccharides or complex carbohydrates.

15. Carbohydrates What type of sugar is found in the following? Small (simple) sugar molecules Examples? • Monosaccharides Glucose Fructose • Disaccharides Lactose Sucrose Long starch molecules in pasta, potatoes Examples? • Polysaccharides Starch Cellulose These are our primary sources of dietary energy In plants, carbs used as building material

16. Monosaccharides What type of sugar is found a sports drink? Glucose What type of sugar is found in fruit? Fructose

17. What about honey? Its really sweet? Why? It contains both glucose and fructose

18. Glucose and Fructose Have the same formula… C6H12O6 Why are they ‘different’? They are isomers

19. Form rings in aqueous solutions Which sugar is this? Glucose

20. Disaccharides Are ‘double sugars’ What are they constructed from? 2 monosaccharides

21. Disaccharides Maltose: glucose and glucose Lactose: galactose and glucose Sucrose: glucose and fructose

22. Lactose, another disaccharide • Some people have trouble digesting lactose • Its a condition called lactose intolerance • Missing gene for lactase enzyme

23. Sucrose The most common disaccharide is sucrose, what do you know it as? Common table sugar What plants do we use to extract table sugar? Sugar cane Roots of sugar beets

24. Polysaccharides Are long chains of sugar units (monosaccharides) (polymers) What are some polysaccharides? Starch Glycogen Cellulose

25. Starch Potatoes and grains are major sources of starch in the human diet Glycogen Liver, muscle cells break down glycogen to release glucose when needed for energy Cellulose Structural component, dietary fiber

26. Complex Carbohydrates • Four polysaccharides are critical in the living world: • starch • glycogen • cellulose • chitin

27. Four Complex Carbohydrates (a) Potato (b) Liver (c) Algae (d) Tick Starch Glycogen Cellulose Chitin

28. Biological Macromolecule: Carbohydrates Function: Monomer: • Dietary energy • Storage • Plant structure Examples: • Monosaccharides (simple sugars) (glucose, fructose) • Disaccharides (double sugars) (maltose, lactose, sucrose) • Polysaccharides (long polymers) (starch, glycogen, cellulose)

29. Starch is the nutrient storage form of carbohydrates in plants. • Glycogen is the nutrient storage form of carbohydrates in animals.

30. Lipids Butter, lard, margarine, and salad oil Do these lipids mix well with water? Lipids do not possess the monomers-to-polymers structure seen in other biological molecules; no one structural element is common to all lipids. Among the most important lipids are the triglycerides, composed of a glyceride and three fatty acids. Most of the fats that human beings consume are triglycerides.

31. Lipids This diverse group of molecules includes? Fatty acids (energy storage, cushioning, insulation) A biological compound consisting of three fatty acids linked to one glycerol molecule Steroids (cholesterol, in membranes) Characterized by a carbon skeleton consisting of four rings with various functional groups attached

32. Fatty Acids triglycerides Technically called? A fat molecule: Glycerol 3 Fatty acids ‘saturated’ ‘unsaturated’ Double bond ‘unsaturated”

33. Unsaturated fatty acids (plant oils) Have less than the maximum number of hydrogens bonded to the carbons Saturated fatty acids (butter) Have the maximum number of hydrogens bonded to the carbons

34. Double Bonds What is the significance of the number of double bonds in the hydrocarbon tails? • Unsaturated fats tend to be liquids at room temperature Example? vegetable oils Impact on health? unsaturated fats are safer • Saturated fats are solid at room temperature Example? butter and lard Impact on health? Saturated fats in the diet can lead to heart disease

35. Steroids How does the structure differ from fatty acids? Ring structure, various functional groups How does the function differ from fatty acids? Functional groups affect function • causes differences between the hormones estrogen and testosterone Example? (anatomical and physical development) • cholesterol in membranes

36. Steroids (a) Four-ring steroid structure (b) Side chains make each steroid unique testosterone cholesterol estrogen

37. Phospholipids • A third class of lipids is the phospholipids, each of which is composed of two fatty acids, glycerol, and a phosphate group. • The material forming the outer membrane of cells is largely composed of phospholipids.

38. Waxes • A fourth class of lipids is the waxes, each of which is composed of a single fatty acid linked to a long-chain alcohol. • Waxes have an important “sealing” function in the living world. • Almost all plant surfaces exposed to air, for example, have a protective covering made largely of wax.

39. Biological Macromolecule: Lipids Function: Monomer: • Long term energy storage • Hormones Examples: (triglycerides) • Fats, oils (butter, lard, margarine, salad ols) • Steroids (lipid rings) (cholesterol, hormones)

40. Proteins What is a protein? Proteins are an extremely diverse group of biological molecules composed of the monomers called amino acids. • Constructed from a set of 20 different monomers

41. Proteins • Sequences of amino acids are strung together to produce polypeptide chains, which then fold up into working proteins. • Important groups of proteins include enzymes, which hasten chemical reactions, and structural proteins, which make up such structures as hair.

42. Types of Protein

43. The Monomers What does each amino acid monomer consist of? Amino group Carboxyl group • A central carbon atom • Bonded to four covalent partners • Each side group is unique • Identifies each amino acid’s characteristics

44. Examples of 2 different amino acids and their side groups

45. Beginnings of a Protein The linkage of several amino acids . . . ala gln ile ala gln ile A typical protein would consist of hundreds of amino acids . . . produces a polypeptide chain like this:

46. Structure Proteins are complex! Primary • To simplify, we’ll describe them in terms of 4 levels of structure: • a particular # and sequence of amino acids Secondary • turns and folds, alpha helix, pleated sheet Tertiary • irregular loops and folds, 3-D shape Quaternary • 2 or more polypeptides combined

47. Levels of Protein Structure Four Levels of Structure In Proteins (a) Primary structure The primary structure of any protein is simply its sequence of amino acids. This sequence determines everything else about the protein’s final shape. amino acid sequence (b) Secondary structure Structural motifs, such as the corkscrew-like alpha helix, beta pleated sheets, and the less organized “random coils” are parts of many polypeptide chains, forming their secondary structure. alpha helix random coil beta pleated sheet (c) Tertiary structure These motifs may persist through a set of larger-scale turns that make up the tertiary structure of the molecule folded polypeptide chain (d) Quaternary structure Several polypeptide chains may be linked together in a given protein, in this case hemoglobin, with their configuration forming its quaternary structure. two or more polypeptide chains

48. Biological Macromolecule: Proteins Monomer: Function: Carboxyl group Amino group • Many! • Change rate of reaction • Carry molecules • Cell communication Examples: • Enzyme (lactase) • Transport (hemoglobin) = 20 amino acids • Defense (antibodies)

49. Biological Molecules

50. Nucleic Acids What are nucleic acids? The cells information storage molecules • There are two types of nucleic acids • DNA, deoxyribonucleic acid RNA, ribonucleic acid • These ‘work together’ to synthesize protein