The Molecules of Life

1. The Molecules of Life

2. Organic Compounds • What does organic mean? • No pesticides? • Environmentally friendly farming? • In biology, organic = carbon based molecules.

3. Hydrocarbons • Hydrocarbons are long chains of carbons bonded to hydrogen atoms • C-H bond = high energy • Hydrocarbons are a good energy source Fats are mostly hydrocarbons Octane is a hydrocarbon. It is one of the main components of gasoline.

4. Hydrocarbons • Why does our body store fat? • C-H bonds are high energy • Fat is an efficient way to store a lot of energy in a small molecule (9 Calories/gram) • Excess calories  fat

5. Functional Groups • Functional groups are common groupings of atoms that give molecules predictable properties Carboxyl group -makes molecules acidic Amino group -makes molecules basic

6. Alcohol! • All alcohols are carbon based compounds with a hydroxyl group hydroxyl group ethanol (drinking alcohol) Is sugar an alcohol?

7. Carbonyl group • A carbonyl group consists of a carbon atom double bonded to an oxygen atom Acetone Have you ever used acetone?

8. Carboxyl group • A carboxyl group is a carbonyl group + a hydroxyl group • Carboxyl groups make many molecules acidic. • Molecule with carboxyl group = carboxylic acid Ethanoic acid = vinegar

9. Amino group • Nitrogen bonded to two hydrogens • Makes molecules basic (opposite of acidic) Amino acid Building block of proteins

10. Phosphate group • Phosphate group = phosphorus bonded to four oxygen atoms • Used in DNA backbone • Used in ATP ATP

11. Methyl group • Methyl group = carbon bonded to three hydrogens • Sometimes written CH3 How many methyl groups does acetone have?

12. Testosterone v. Estradiol • A few functional groups can make a big difference! testosterone estradiol (estrogen) Can you spot the differences?

13. Office Hours • Tonight, 7:00 - 8:00 • Missing work? You’re invited! • Mandatory • Alvaro Gonzalez • Jane McCaffrey • Richard Fagan • Gavin Rudolph • Kenrick Vincent • Nate Gilbert • Stanley Yao • Ben Lieber

15. Polymers • A polymer is a large molecule made of many similar building blocks strung together • Each building block is called a monomer Proteins are polymers made of amino acids DNA is a polymer of nucleic acids

16. Building Polymers • Polymers are put together by dehydration synthesis • Dehydration = lose water • Synthesis = putting together

17. Dehydration Synthesis • Proteins are made by dehydration synthesis • Building blocks = amino acids Synthesizing proteins from amino acids

18. Dehydration Synthesis • Sugars can be made into polymers too • Sugars are joined by dehydration synthesis

19. Hydrolysis • Hydrolysis is the disassembly of polymers by adding water back in • It is the opposite of dehydration synthesis Hydrolysis of proteins Hydrolysis of starches

20. Lactose Intolerance • Lactose intolerance is the inability to digest milk and dairy products • Look at lactose: what kind of molecule is it? • People with lactose intolerance can’t hydrolyze lactose. lactose

21. Acids and Bases • Water naturally ionizes into H+ and –OH ions at a low frequency • Neutral water: H+ and –OH are balanced • Acidic solution: H+ > -OH • Basic solution: -OH >H+

23. pH Scale • The pH scale describes how acidic or basic a solution is • 0-14 • 0 = most acidic • 7 = neutral • 14 = most basic • Each step is a tenfold decrease in H+ ions and a tenfold increase in –OH ions

24. Practice! • Rate each as acidic, basic, or neutral • Rank from greatest to least concentration of H+ pH = 7 pH = 3 pH = 9

25. Carbohydrates • Carbohydrates are a class of molecules that include sugars and starches • Their chemical formula is usually a multiple of CH2O (carbon + water = carbo hydrate) • Carbohydrates are the primary energy source for our bodies

26. Carbohydrates • Simple, single unit sugars are called monosaccharides • Mono = 1 • Saccharide = sugar Glucose C6H12O6 Ribose C5H10O5

28. Carbohydrates • Two monosaccharides can be linked by dehydration synthesis to form a disaccharide • Di = 2

29. Carbohydrates • Polysaccharides are polymers of hundreds to thousands of simple sugars • Poly = many • Starch, glycogen, and cellulose are all polymers of glucose molecules

30. Carbohydrates • Starch is a polysaccharide used for energy storage in plants • Animals can digest starch and use it for energy. • Where do you get starch from?

31. Carbohydrates • Glycogen is a polysaccharide used for energy storage in humans • Stored in liver and muscles • Branched chains of glucose monomers

32. Carbohydrates • Cellulose is a polysaccharide used to build the rigid cell walls of plants. • Dietary fiber • Wood

33. 10/7/11 • Objective: To expand our knowledge of lipids • Do now: In your notes, define a hydrocarbon and list some of its properties • Do later: Make and study flashcards for all the bolded words from pg. 36-41

34. High Fructose Corn Syrup • Normal table sugar = 50% glucose, 50% fructose • HFCS = 55% fructose, 45% glucose

35. Hydrophilic v. Hydrophobic • New words for an old idea: solubility effects • Hydrophilic = polar/dissolves in H2O • Polar functional groups: • Amino • Carbonyl • Hydroxyl • Carboxyl • Phosphate

36. Hydrophilic v. Hydrophobic • Hydrophobic = non-polar/doesn’t dissolve in water • Non-polar functional groups • Methyl (CH3)

37. Lipids! • Lipids = fats, oils, steroids • Hydrophobic • Mostly made of carbon and hydrogen •  mostly non-polar covalent bonds

38. Fats • Fats = glycerol + 3 fatty acids • Glycerol = alcohol • Fatty acid = carboxylic acid with long hydrocarbon chain • Hydrocarbon chains make fats hydrophobic  + 3 Triglyceride (fat molecule) Glycerol + 3 fatty acids

39. Saturated v. Unsaturated Fats • Saturated = fatty acid with no double bonds • Unsaturated = fatty acid with double bonds

40. Saturated v. Unsaturated Fats • Saturated = solid at room temperature • Unsaturated = liquid at room temperature • What are some examples?

41. Saturated v. Unsaturated Fats • Saturated = Straight chain packs into a solid easily • Unsaturated = Kinks in chain keep unsaturated fat from solidifying

42. Science in Popular Media • What’s right/wrong in this video?

43. 10/10/11 • Objective: To explore the diversity of lipids and the structure of proteins • Do now: Take a quiz and go! • Do later: Read and outline pgs 42-44 • Outlines: • Main concepts • Important diagrams/drawings • Bolded vocabulary • Other helpful notes

44. Hydrogenated Oils • Oils that are chemically hydrogenated (add hydrogen) to become saturated fats.

45. Hydrogenated Oils • Why hydrogenate oils? • Solid fats create better texture in many foods • Hydrogenated oils are much less expensive than animal fat

46. Hydrogenated Oils • Is this a bad thing? • Maybe. Hydrogenation of oils creates trans fats, which are linked to heart disease

47. Why fat? • Fats contain 9 Calories/gram • Sugars & proteins = 4 Calories/gram • Fat = more efficient energy storage than proteins/sugars • Stored in specialized fat cells

48. Phospholipids • Made of glycerol, two fatty acids, and a phosphate head • Fatty acids are hydrophobic (non-polar) • Phosphate head is hydrophilic (polar)

49. Phospholipids • Cell membranes are made of a bilayer of phospholipids • Hydrophobic tails on the inside • Hydrophilic heads on the outside

50. Steroids • Steroids are lipids containing four fused rings • Many steroids are hormones • Cholesterol is a major component of cell membranes Testosterone Estradiol