1. CHAPTER 3: THE CHEMISTRY OF LIFE The Structure and Function of Large Biomolecules

2. Intro Recap  Essential Elements - CHONPS  Carbon  Hydrogen  Oxygen  Nitrogen  Phosphorus  Sulfur  Make up the 4 major molecules in your body  Carbs  Proteins  Lipids  Nucleic acids

3. Macromolecules  Huge molecules made of many smaller molecules and atoms  Carbohydrates  Proteins  Nucleic Acids  Lipids don’t count!

4. Polymers and Monomers  mono = one  Subunits of polymer  poly = many  One polymer is made up of many monomers bonded together MonomerPolymer Sugar

5. Dehydration Synthesis = Condensation  The way that polymers are assembled  Dehydration – water is removed  Synthesis – to make  Remove water to make a bond

6. Fig. 5-2a Dehydration removes a water molecule, forming a new bond Short polymerUnlinked monomer Longer polymer Dehydration reaction in the synthesis of a polymer HO H2OH2O H H H 4 3 2 1 1 2 3 (a)

7. Hydrolysis  The way that polymers are broken down (metabolized)  Hydro – water  Lysis – to cut/break  Add water to break a bond  Where does a lot of hydrolysis happen?

8. Fig. 5-2b Hydrolysis adds a water molecule, breaking a bond Hydrolysis of a polymer HO H2OH2O H H H 3 2 1 1 23 4 (b)

9. Carbohydrates  Sugars and their polymers  Monosaccharides – one sugar (building block)  Disaccharides – two sugars  Polysaccharides – many sugars  Multiple of the unit CH 2 O  Glucose C 6 H 12 O 6

10. Sugars  Can be chains or rings (3-7 carbons long)  Have a carbonyl group (>C=O)  Many hydroxyl groups (–OH) Aldoses Glyceraldehyde Ribose GlucoseGalactose Hexoses (C 6 H 12 O 6 ) Pentoses (C 5 H 10 O 5 ) Trioses (C 3 H 6 O 3 )

11. Fig. 5-4a (a) Linear and ring forms

12. Fig. 5-4b (b) Abbreviated ring structure

13. Starch – a polymer of glucose  Plants store sugars for later use (inside plastids)

14. Functions of carbs in animals  Glucose: chemical fuel for respiration (mono)  Lactose: makes up some solutes in milk (di)  Glycogen: glucose storage in liver and muscles (poly)

15. Functions of carbs in plants  Fructose: found in fruits; make them sweet (mono)  Sucrose: transported through phloem (di)  Cellulose: components of cell walls (poly)

16. Fig. 5-8 b Glucose monomer Cellulose molecules Microfibril Cellulose microfibrils in a plant cell wall 0.5 µm 10 µm Cell walls

17. Starch and Cellulose Digestion  Enzymes that digest starch by hydrolyzing  linkages can’t hydrolyze  linkages in cellulose  Cellulose in human food passes through the digestive tract as insoluble fiber

18. Chitin – a structural polysaccharide  Found in the exoskeleton of arthropods  Structural support for the cell walls of many fungi

19. Lipids  Hydrophobic – they mix poorly with water  Mostly hydrocarbon regions – nonpolar

20. Fats - CHO  1 glycerol (alcohol with 3 carbons) + 3 fatty acids (long chain of CH connected to carboxyl) Fatty acid (palmitic acid) (a) Dehydration reaction in the synthesis of a fat Glycerol

21. Fig. 5-11b (b) Fat molecule (triacylglycerol) Ester linkage Esterification

22. Saturated vs. Unsaturated  have the maximum number of hydrogen atoms possible and no double bonds  have one or more double bonds Saturated fatty acids Unsaturated fatty acids

23. Animal vs. Plant  Most animal fats  No double bonds makes the tail flexible  They can pack together tightly  Solid at room temp  Most plant fats (oils)  Double bonds makes them bent  Can’t pack together  Liquid at room temp  Hydrogenated = added Hs to make them saturated Saturated FatsUnsaturated Fat

24. What do fats do?  Too much saturated fat is bad for you  Atherosclerosis – plaques of fat in blood vessels  Hydrogenation forms trans fats – even worse!  Store lots of energy  2x as much as carbs!  Cushions vital organs  Insulates the body Bad thingsGood things

25. Phospholipids – make up cell membranes (b) Space-filling model (c) Structural formula Phospholipid symbol Fatty acids Hydrophilic head Hydrophobic tails Choline Phosphate Glycerol Hydrophobic tails Hydrophilic head  One fatty acid is replaced by a phosphate

26. Phospholipid Bilayer – Cell Membrane Polar Phosphate Heads Non-Polar Fatty Acid Tails

27. Steroids  4 fused carbons rings  Hormones – cell to cell signaling (long distance)  Cholesterol – stabilizes cell membranes  Made in liver  Too much is bad

28. Other functions of lipids  Protection of vital organs  To insulate the body  They form the myelin sheath around some neurons

29. Proteins – CHON(S)  Needed for almost everything that happens in your cells/body FunctionExample EnzymesAmylase TransportHemoglobin MovementActin, myosin Cell RecognitionAntigens ChannelsMembrane Proteins StructureCollagen, keratin HormonesInsulin ProtectionAntibodies

30. Polypeptides  Polymers of animo acids  Not a protein – doesn’t have full structure

31. R groups – ~20 in humans  The R group’s structure determines the property of the amino acid  Example: Alanine = CH 3 CH 3 is nonpolar and so is Alanine Alanine (Ala or A)

32. Fig. 5-17a Nonpolar Glycine (Gly or G) Alanine (Ala or A) Valine (Val or V) Leucine (Leu or L) Isoleucine (Ile or I ) Methionine (Met or M) Phenylalanine (Phe or F) Tryptophan (Trp or W) Proline (Pro or P)

33. Fig. 5-17b Polar Asparagine (Asn or N) Glutamine (Gln or Q) Serine (Ser or S) Threonine (Thr or T) Cysteine (Cys or C) Tyrosine (Tyr or Y)

34. Fig. 5-17c Acidic Arginine (Arg or R) Histidine (His or H) Aspartic acid (Asp or D) Glutamic acid (Glu or E) Lysine (Lys or K) Basic Electrically charged

35. Peptide Bond (“polypeptide”)  Made by dehydration synthesis (condensation)

36. Nucleic Acids - CHONP  Polymer – nucleic acid  Monomer - nucleotide  Hold the information to make polypeptides (on genes)

37. Nucleic Acids  Each nucleotide has 3 parts:  Nitrogenous base  Sugar  Phosphate group

38. Sugars  Always 5 carbons:  Ribose – RNA  Deoxyribose – DNA

39. Nitrogenous Bases  Nitrogen containing rings (c) Nucleoside components: nitrogenous bases Purines Guanine (G) Adenine (A) Cytosine (C) Thymine (T, in DNA)Uracil (U, in RNA) Nitrogenous bases Pyrimidines

40. Double Helix  DNA strands are complementary  A—T  C—G

41. Double Helix  Spiral shape of DNA coil  Held together by H- bonds between bases  And van der Waals attractions