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AP Biology Chapter 3: Structure and Function of Macromolecules (Independently brush up on Ch 2 and Ch 3.1)

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Presentation on theme: "AP Biology Chapter 3: Structure and Function of Macromolecules (Independently brush up on Ch 2 and Ch 3.1)"— Presentation transcript:

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2 AP Biology Chapter 3: Structure and Function of Macromolecules (Independently brush up on Ch 2 and Ch 3.1)

3 Enduring Understandings / IV. A. Interactions within biological systems lead to complex properties. / 1. The subcomponents of biological molecules and their sequence determine the properties of that molecule. / B. Competition and cooperation are important aspects of biological systems. / 1. Interactions between molecules affect their structure and function. / C. Naturally occurring diversity among and between components within biological systems affects interactions with the environment. / 1. Variation in molecular units provides cells with a wider range of functions. / IV. A. Interactions within biological systems lead to complex properties. / 1. The subcomponents of biological molecules and their sequence determine the properties of that molecule. / B. Competition and cooperation are important aspects of biological systems. / 1. Interactions between molecules affect their structure and function. / C. Naturally occurring diversity among and between components within biological systems affects interactions with the environment. / 1. Variation in molecular units provides cells with a wider range of functions.

4 Macromolecules  Smaller organic molecules join together to form larger molecules  macromolecules  4 major classes of macromolecules:  carbohydrates  lipids  proteins  nucleic acids

5 H2OH2O HO H HH Polymers  Long molecules built by linking repeating building blocks in a chain  monomers  building blocks  repeated small units  covalent bonds

6 H2OH2O HO H HH How to build a polymer  Synthesis  joins monomers by “taking” H 2 O out  one monomer donates OH –  other monomer donates H +  together these form H 2 O  requires energy & enzymes enzyme Dehydration synthesis - Condensation reaction, in which the lost molecule = H 2 O Condensation reaction

7 Dehydration Synthesis

8 H2OH2O HOH H H How to break down a polymer  Digestion  use H 2 O to breakdown polymers  reverse of dehydration synthesis  cleave off one monomer at a time  H 2 O is split into H + and OH –  H + & OH – attach to ends  requires hydrolytic enzymes  releases energy Hydrolysis enzyme

9 Discussion  Under what circumstances would you expect to find a cell conducting a great deal of dehydration synthesis ?  In which organs or under what circumstances would you expect to find body cells conducting hydrolysis ?

10 Variety of Polymers  Every cell has thousands of varieties of macromolecules  These molecules are constructed from only 40 to 50 common monomers  Analogy: 26 letters of the alphabet can be combined to form millions of words  Shortcoming: macromolecules are much longer than the average word and they can be branched or 3D.

11 Carbohydrates

12 a.k.a. wheeee energy! :D

13 Carbohydrates  Carbohydrates are composed of C, H, O carbo - hydr - ate CH 2 O) x C 6 H 12 O 6  Function:  energy u energy storage  raw materials u structural materials  Monomer: sugars (monosaccharide) sugar C 6 H 12 O 6 (CH 2 O) x

14 Sugars  Most names for sugars end in - ose  Classified by number of carbons  6C = hexose (glucose)  5C = pentose (ribose)  3C = triose (glyceraldehyde) 653

15 Sugar structure 5C & 6C sugars form rings in solution

16 Numbered carbons C CC C C C 1' 2'3' 4' 5' 6' O energy stored in bonds You’ll see this come back in our DNA unit…

17 Simple & complex sugars  Monosaccharides  simple 1 monomer sugars  Ex: glucose, galactose  Disaccharides  2 monomers  Ex: sucrose, lactose  Polysaccharides  3+ monomers  Ex: starch, cellulose, glycogen

18 Building sugars  Dehydration synthesis to form glycosidic bond | fructose | glucose monosaccharides | sucrose (table sugar) disaccharide H2OH2O

19 Polysaccharides  Polymers of sugars  costs little energy to build  easily reversible = release energy  Functions:  energy storage  starch (plants)  glycogen (animals)  in liver & muscles  structure  cellulose (plants)  chitin (arthropods & fungi)

20 Polysaccharide diversity  Molecular structure determines function - a major theme!  Isomers of glucose  Different structure = connect to the next monomer in the chain differently = different 3D structure.  Starch - helical. Cellulose - straight, with free OH to bond to neighboring celluloses = rigid structure! in starch in cellulose

21 Cellulose  Most abundant organic compound on Earth  herbivores have evolved a mechanism to digest cellulose  most carnivores have not  that’s why they eat meat to get their energy & nutrients  cellulose = undigestible roughage

22 Helpful bacteria  How can herbivores digest cellulose so well?  BACTERIA live in their digestive systems & help digest cellulose-rich (grass) meals Ruminants

23 Discussion  In EXACTLY 20 words, summarize the most important point or points to remember about carbohydrates.

24 Lipids: Fats & Oils

25 Enduring Understandings / IV. A. Interactions within biological systems lead to complex properties. / 1. The subcomponents of biological molecules and their sequence determine the properties of that molecule. / B. Competition and cooperation are important aspects of biological systems. / 1. Interactions between molecules affect their structure and function. / C. Naturally occurring diversity among and between components within biological systems affects interactions with the environment. / 1. Variation in molecular units provides cells with a wider range of functions. / IV. A. Interactions within biological systems lead to complex properties. / 1. The subcomponents of biological molecules and their sequence determine the properties of that molecule. / B. Competition and cooperation are important aspects of biological systems. / 1. Interactions between molecules affect their structure and function. / C. Naturally occurring diversity among and between components within biological systems affects interactions with the environment. / 1. Variation in molecular units provides cells with a wider range of functions.

26 Lipid Primary Function: long term energy storage concentrated energy

27 Lipids  Lipids are composed of C, H, O  long hydrocarbon chains (H-C)  “Family groups”  fats  phospholipids  steroids  Do not form polymers  big molecules made of smaller subunits  not a continuing chain Same as carbohydrates, but different structure = different function!

28 Fats  Structure:  glycerol (3C alcohol) + fatty acid  fatty acid = long HC “tail” with carboxyl (COOH) group “head” dehydration synthesis H2OH2O enzyme

29 Building Fats  Triglycerol  3 fatty acids linked to glycerol  ester linkage between OH & COOH hydroxylcarboxyl

30 Dehydration synthesis dehydration synthesis H2OH2OH2OH2OH2OH2OH2OH2O enzyme

31 Discussion  What kind of molecule would you expect to be hydrophobic - polar or non-polar?  Why?  Do you think lipids (such as fats, oils, waxes) are probably polar or non-polar?  Why?

32 Fats store energy  Long HC chain  polar or non-polar?  hydrophilic or hydrophobic?  Functions:  energy storage  2x carbohydrates  cushion organs  membranes & waterproofing  insulates body  think whale blubber!

33 Discussion  Show me a human who doesn’t want to eat this and I’ll show you a LIAR. LIESSSSSSS  Knowing their major functions, hypothesize: what occurred in evolutionary history that led to humans enjoying the tastes of fatty and sugary foods?

34 Structure & Function  Saturated Fats  All C bonded to H  No C=C double bonds  long, straight chain  most animal fats  solid at room temp.  contributes to cardiovascular disease (atherosclerosis) = plaque deposits

35 Structure & Function  Unsaturated Fats  C=C double bonds in the fatty acids  plant & fish fats  vegetable oils  liquid at room temperature  the kinks made by double bonded C prevent the molecules from packing tightly together

36 Discussion  Unsaturated fats are widely considered to be healthier (sometimes called “good fats” for short) than saturated fats.  Why might this be? (Hint: think of their structures, and what they might mean for how easily the body would use them for energy vs. storing them in fat cells)

37 Phospholipids  Structure:  glycerol + 2 fatty acids + PO 4  PO 4 = negatively charged

38 Phospholipids  Hydrophobic or hydrophilic?  fatty acid tails =  PO 4 head =  split “personality” interaction with H 2 O is complex & very important! “repelled by water” “attracted to water” hydrophobic hydrophillic

39 Phospholipids in water  Hydrophilic heads “attracted” to H 2 O  Hydrophobic tails “hide” from H 2 O  can self-assemble into “bubbles” called micelles  can also form a phospholipid bilayer  Early Earth history - a cell part that self-assembles! bilayer water

40 Why is this important?  Phospholipids create a barrier in water  define outside vs. inside  they make cell membranes !

41 Steroids  Structure:  4 fused C rings + ??  different steroids created by attaching different functional groups to rings  different structure creates different function  examples: cholesterol, sex hormones cholesterol

42 Cholesterol  Important cell component  animal cell membranes  precursor of all other steroids  including vertebrate sex hormones  high levels in blood contribute to cardiovascular disease

43 Cholesterol helps keep cell membranes fluid & flexible Important component of cell membrane

44 From Cholesterol  Sex Hormones  What a big difference a few atoms can make!

45 Discussion  In EXACTLY 20 words, summarize the most important point or points to remember about lipids.

46 Nucleic Acids Information storage

47 Enduring Understandings / IV. A. Interactions within biological systems lead to complex properties. / 1. The subcomponents of biological molecules and their sequence determine the properties of that molecule. / B. Competition and cooperation are important aspects of biological systems. / 1. Interactions between molecules affect their structure and function. / C. Naturally occurring diversity among and between components within biological systems affects interactions with the environment. / 1. Variation in molecular units provides cells with a wider range of functions. / IV. A. Interactions within biological systems lead to complex properties. / 1. The subcomponents of biological molecules and their sequence determine the properties of that molecule. / B. Competition and cooperation are important aspects of biological systems. / 1. Interactions between molecules affect their structure and function. / C. Naturally occurring diversity among and between components within biological systems affects interactions with the environment. / 1. Variation in molecular units provides cells with a wider range of functions.

48 proteins DNA Nucleic Acids  Function:  genetic material  stores information  genes  blueprint for building proteins DNA  RNA  proteins  transfers information  blueprint for new cells  blueprint for next generation

49 Nucleic Acids  Examples:  RNA (ribonucleic acid)  single helix  DNA (deoxyribonucleic acid)  double helix  Structure:  monomers = nucleotides RNA DNA

50 Nucleotides  3 parts  nitrogen base (C-N ring)  pentose sugar (5C)  ribose in RNA  deoxyribose in DNA  phosphate (PO 4 ) group Nitrogen base I’m the A,T,C,G or U part!

51 Types of nucleotides  2 types of nucleotides  different nitrogen bases  purines  double ring N base  adenine (A)  guanine (G)  pyrimidines  single ring N base  cytosine (C)  thymine (T)  uracil (U) Purine = AG “Pure silver!”

52 Nucleic polymer  Backbone  sugar to PO 4 bond  phosphodiester bond  new base added to sugar of previous base  dehydration synthesis again!  polymer grows in one direction  N bases hang off the sugar-phosphate backbone Dangling bases? Why is this important?

53 Pairing of nucleotides  Nucleotides bond between DNA strands  H bonds  purine :: pyrimidine  A :: T  2 H bonds  G :: C  3 H bonds Matching bases? Why is this important?

54 DNA molecule  Double helix  H bonds between bases join the 2 strands  A :: T  C :: G  Like carbohydrates, strands have direction that matters to structure  The end with a dangling phosphate (5’) can’t have any more bases added to it, unlike the other end (3’) H bonds? Why is this important?

55 Copying DNA  Replication  2 strands of DNA helix are complementary  have one, can build other  have one, can rebuild the whole Matching halves? Why is this a good system?

56 Interesting note…  Ratio of A-T::G-C affects stability of DNA molecule  2 H bonds vs. 3 H bonds  biotech procedures  more G-C = need higher T° to separate strands  high T° organisms  many G-C  parasites  many A-T (don’t know why)

57 Another interesting note…  ATP Adenosine triphosphate ++  modified nucleotide  adenine (AMP) + P i + P i

58 Discussion  In EXACTLY 20 words, summarize the most important point or points to remember about nucleic acids.

59 Proteins Multipurpose molecules

60 Enduring Understandings / IV. A. Interactions within biological systems lead to complex properties. / 1. The subcomponents of biological molecules and their sequence determine the properties of that molecule. / B. Competition and cooperation are important aspects of biological systems. / 1. Interactions between molecules affect their structure and function. / C. Naturally occurring diversity among and between components within biological systems affects interactions with the environment. / 1. Variation in molecular units provides cells with a wider range of functions. / IV. A. Interactions within biological systems lead to complex properties. / 1. The subcomponents of biological molecules and their sequence determine the properties of that molecule. / B. Competition and cooperation are important aspects of biological systems. / 1. Interactions between molecules affect their structure and function. / C. Naturally occurring diversity among and between components within biological systems affects interactions with the environment. / 1. Variation in molecular units provides cells with a wider range of functions.

61 Proteins  Most structurally & functionally diverse group  Function: involved in almost everything  enzymes (pepsin, DNA polymerase)  structure (keratin, collagen)  carriers & transport (hemoglobin, aquaporin)  cell communication  signals (insulin & other hormones)  receptors  defense (antibodies)  movement (actin & myosin)  storage (bean seed proteins)

62 Proteins  Structure  monomer = amino acids  20 different amino acids  polymer = polypeptide  protein can be one or more polypeptide chains folded & bonded together  large & complex molecules  complex 3-D shape Rubisco hemoglobin growth hormones H2OH2O

63 Amino acids  Structure  central carbon  amino group  carboxyl group (acid)  R group (side chain)  variable group  different for each amino acid  confers unique chemical properties to each amino acid  like 20 different letters of an alphabet  can make many words (proteins) —N——N— H H C—OH || O R | —C— | H

64 Effect of different R groups: Nonpolar amino acids  nonpolar & hydrophobic

65 Effect of different R groups: Polar amino acids  polar or charged & hydrophilic

66 Ionizing in cellular waters H+ donors

67 Ionizing in cellular waters H+ acceptors

68 Sulfur containing amino acids  Form disulfide bridges  covalent cross links betweens sulfhydryls  stabilizes 3-D structure H-S – S-H

69 Building proteins  Peptide bonds  covalent bond between NH 2 (amine) of one amino acid & COOH (carboxyl) of another  C–N bond peptide bond dehydration synthesis H2OH2O

70 Building proteins  Like carbs & nucleic acids, polypeptides have direction that matters!  N-terminus = NH 2 end  C-terminus = COOH end  repeated sequence (N-C-C) is the polypeptide backbone  can only grow in one direction, N -> C

71 Protein structure & function hemoglobin  Function depends on structure  3-D structure  twisted, folded, coiled into unique shape collagen pepsin

72 Primary (1°) structure  Order of amino acids in chain  amino acid sequence determined by gene (DNA)  slight change in amino acid sequence can affect protein’s structure & its function  even just one amino acid change can make all the difference! Remember sickle-cell anemia? lysozyme: enzyme in tears & mucus that kills bacteria

73 Sickle cell anemia I’m hydrophilic! I’m hydrophobic! Just 1 out of 146 amino acids! Non- polar valine “tries to hide” from water of cell by sticking to another hemoglobin molecule

74 Secondary (2°) structure  “Local folding”  folding along short sections of polypeptide  interactions between adjacent amino acids  H bonds  weak bonds between R groups  forms sections of 3-D structure   -helix   -pleated sheet

75 Secondary (2°) structure

76 Tertiary (3°) structure  “ Whole molecule folding ”  interactions between distant amino acids  hydrophobic interactions  cytoplasm is water-based  nonpolar amino acids cluster away from water  H bonds & ionic bonds  disulfide bridges  covalent bonds between sulfurs in sulfhydryls (S – H)  anchors 3-D shape

77 Quaternary (4°) structure  More than one polypeptide chain bonded together  only then does polypeptide become functional protein Collagen = skin & tendon structure Hemoglobin = holds O 2

78 Sequence -> Structure Structure -> Function amino acid sequence peptide bonds 1° determined by DNA R groups H bonds R groups hydrophobic interactions disulfide bridges (H & ionic bonds) 3° multiple polypeptides hydrophobic interactions 4° 2°

79 Protein denaturation  Unfolding a protein  conditions that disrupt H bonds, ionic bonds, disulfide bridges  temperature  pH  salinity  alter 2° & 3° structure  alter 3-D shape  destroys functionality  some proteins can return to their functional shape after denaturation, many cannot

80 Discussion  In EXACTLY 20 words, summarize the most important point or points to remember about proteins.

81 Macromolecule Review

82 Carbohydrates  Structure / monomer  monosaccharide  Function  energy  raw materials  energy storage  structural compounds  Examples  glucose, starch, cellulose, glycogen glycosidic bond

83 Lipids  Structure / building block  glycerol, fatty acid, cholesterol, H-C chains  Function  energy storage  membranes  hormones  Examples  fat, phospholipids, steroids

84 Nucleic acids  Structure / monomer  nucleotide  Function  information storage & transfer  Examples  DNA, RNA phosphodiester bond

85 Proteins  Structure / monomer  amino acids  levels of structure  Function  enzymes u defense  transport u structure  signals u receptors  Examples  digestive enzymes, membrane channels, insulin hormone, actin peptide bond

86 Discussion  In EXACTLY 20 words, summarize the major theme/s in studying biomacromolecules. (And no, wise guy, I don’t mean “they’re hard.”)


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