1<br />Carbon and the Molecular Diversity of Life<br />
2<br />Figure 4.1<br />Carbon Chemistry<br />Carbon is the Backbone of Biological Molecules (macromolecules)<br />All livi...
3<br />Ball-and-Stick Model<br />Name and Comments<br />Space-Filling Model<br />Molecular Formula<br />Structural Formula...
4<br />H<br />H<br />C<br />C<br />C<br />C<br />H<br />H<br />C<br />H<br />H<br />H<br />H<br />H<br />H<br />C<br />H<b...
5<br />Fat droplets (stained red)<br />100 µm<br />(b) Mammalian adipose cells<br />(a) A fat molecule<br />Figure 4.6 A, ...
6<br />H<br />H<br />H<br />C<br />H<br />H<br />C<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />(a) Structural is...
7<br />L-Dopa<br />(effective against Parkinson’s disease)<br />D-Dopa<br />(biologically inactive)<br />Figure 4.8<br />E...
8<br />OH<br />CH3<br />Estradiol<br />HO<br />Female lion<br />OH<br />CH3<br />CH3<br />O<br />Testosterone<br />Male li...
9<br />Six functional groups are important in the chemistry of life<br />Hydroxyl<br />Carbonyl<br />Carboxyl<br />Amino<b...
10<br />FUNCTIONAL<br />GROUP<br />         HYDROXYL                CARBONYL                      CARBOXYL<br />O<br />O<b...
11<br />Ketones if the carbonyl group is within a carbon skeleton <br />Aldehydes if the carbonyl group is at the end of t...
12<br />        AMINO                        SULFHYDRYL                     PHOSPHATE<br />O<br />H<br />SH<br />N<br />P<...
13<br />Macromolecules<br />Most macromolecules are polymers, built from monomers<br /> Four classes of life’s organic    ...
14<br />Carbohydrates<br />Serve as fuel and building material<br />Include both sugars and their polymers (starch, cellul...
15<br />The Synthesis and Breakdown of Polymers<br />1<br />HO<br />H<br />3<br />2<br />HO<br />H<br />Unlinked monomer<b...
16<br />The Synthesis and Breakdown of Polymers<br />1<br />3<br />HO<br />4<br />2<br />H<br />Hydrolysis adds a watermol...
17<br />Triose sugars(C3H6O3)<br />Pentose sugars(C5H10O5)<br />Hexose sugars(C6H12O6)<br />H<br />H<br />H<br />H<br />O<...
18<br />Disaccharides<br />Consist of two monosaccharides<br />Dehydration Synthesis occurs (glycosidic linkage)<br />
19<br />(a)<br />Dehydration reaction in the synthesis of maltose. The bonding of two glucose units forms maltose. The gly...
20<br />Polysaccharides<br />Polysaccharides<br />Are polymers of sugars<br />Serve many roles in organisms<br />
21<br />Storage Polysaccharides<br />Chloroplast<br />Starch<br />1 m<br />Amylose<br />Amylopectin<br />(a) Starch: a pl...
22<br />Giycogen granules<br />Mitochondria<br />0.5 m<br />Glycogen<br />(b) Glycogen: an animal polysaccharide<br />Fig...
23<br />Structural Polysaccharides<br />H<br />O<br />CH2OH<br />C<br />CH2OH<br />OH<br />OH<br />H<br />C<br />H<br />O<...
24<br />About 80 cellulose<br />molecules associate<br />to form a microfibril, the<br />main architectural unit<br />of t...
25<br />CH2OH<br />O<br />OH<br />H<br />H<br />OH<br />H<br />H<br />H<br />NH<br />O<br />C<br />CH3<br />OH<br />(b) Ch...
26<br />Lipids<br />Lipids are a diverse group of hydrophobic molecules<br />Lipids<br />Are the one class of large biolog...
27<br />Fats<br />Are constructed from two types of smaller molecules, a single glycerol and usually three fatty acids<br ...
28<br />Stearic acid<br />Figure 5.12<br />(a)  Saturated fat and fatty acid<br />Saturated fatty acids<br />Have the maxi...
29<br />Oleic acid<br />cis double bond<br />causes bending<br />Figure 5.12<br />(b)  Unsaturated fat and fatty acid<br /...
30<br />+<br />CH2<br />Choline<br />N(CH3)3<br />CH2<br />O<br />Phosphate<br />Hydrophilic head<br />–<br />P<br />O<br ...
31<br />WATER<br />Hydrophilic<br />head         <br />WATER<br />Hydrophobic<br />tail              <br />Figure 5.14<br ...
32<br />H3C<br />CH3<br />CH3<br />CH3<br />CH3<br />HO<br />Figure 5.15<br />Steroids<br />One steroid, cholesterol<br />...
33<br />Proteins<br />Proteins have many structures, resulting in a wide range of functions<br />Proteins do most of the w...
34<br />Table 5.1<br />An overview of protein functions<br />
35<br />Substrate binds to<br />enzyme.          <br />1   Active site is available for<br />     a molecule of substrate,...
36<br />Polypeptides<br />Polypeptides<br />Are polymers (chains) of amino acids<br />A protein<br />Consists of one or mo...
37<br />Amino acids<br />Are organic molecules possessing both carboxyl and amino groups<br />Differ in their properties d...
38<br />Twenty Amino Acids<br />CH3<br />CH3<br />CH3<br />CH<br />CH2<br />CH3<br />CH3<br />H<br />CH3<br />H3C<br />CH3...
39<br />OH<br />NH2<br />O<br />C<br />NH2<br />O<br />C<br />OH<br />SH<br />CH2<br />CH3<br />OH<br />Polar<br />CH2<br ...
40<br />Amino Acid Polymers<br />Amino acids<br />Are linked by peptide bonds<br />
41<br />Protein Conformation and Function<br />A protein’s specific conformation (shape) determines how it functions<br />
42<br />Four Levels of Protein Structure<br />Amino acid subunits<br />+H3NAmino end<br />Pro<br />Thr<br />Gly<br />Gly<b...
43<br />H<br />H<br />H<br />H<br />H<br />H<br />O<br />O<br />O<br />O<br />O<br />O<br />O<br />H<br />H<br />H<br />H<...
44<br />Hydrophobic interactions and van der Waalsinteractions <br />CH<br />CH2<br />CH2<br />H3C<br />CH3<br />OH<br />P...
45<br />Polypeptidechain<br />Collagen<br /> Chains<br />Iron<br />Heme<br /> Chains<br />Hemoglobin<br />Quaternary str...
46<br />Review of Protein Structure<br />+H3N<br />Amino end<br />Amino acid<br />subunits<br />helix<br />
47<br />Sickle-Cell Disease: A Simple Change in  Primary Structure<br />Sickle-cell disease<br />Results from a single ami...
48<br />Normal hemoglobin<br />Sickle-cell hemoglobin<br />Primary structure<br />Primary structure<br />. . .<br />. . .<...
49<br />What Determines Protein Conformation?<br />Protein conformation Depends on the physical and chemical conditions of...
50<br />Denaturation<br />Denatured protein<br />Normal protein<br />Renaturation<br />Figure 5.22<br /><ul><li>Denaturati...
52<br />Correctlyfoldedprotein<br />Polypeptide<br />Cap<br />Hollowcylinder<br />     The cap attaches, causing the cylin...
53<br />Nucleic Acids<br />Nucleic acids store and transmit hereditary information<br />Genes<br />Are the units of inheri...
54<br />The Roles of Nucleic Acids<br />There are two types of nucleic acids<br />Deoxyribonucleic acid (DNA)<br />Ribonuc...
55<br />Deoxyribonucleic Acid<br />DNA<br />Stores information for the synthesis of specific proteins<br />Found in the nu...
56<br />DNA<br />1<br />       Synthesis of            mRNA in the nucleus<br />mRNA<br />NUCLEUS<br />CYTOPLASM<br />mRNA...
57<br />5’ end<br />5’C<br />O<br />3’C<br />O<br />O<br />5’C<br />O<br />3’C<br />3’ end<br />OH<br />Figure 5.26 <br />...
58<br />Nucleoside<br />Nitrogenous<br />base<br />O<br />5’C<br />O<br />O<br />CH2<br />P<br />O<br />O<br />Phosphate...
59<br />Nitrogenous bases Pyrimidines<br />NH2<br />O<br />O<br />C<br />C<br />CH3<br />C<br />N<br />CH<br />HN<br />C<b...
60<br />Nucleotide Polymers<br />Nucleotide polymers<br /> Are made up of nucleotides linked by the–OH group on the 3´ car...
61<br />Gene<br />The sequence of bases along a nucleotide polymer<br />Is unique for each gene<br />
62<br />The DNA Double Helix<br />Cellular DNA molecules<br />Have two polynucleotides that spiral around an imaginary axi...
63<br />3’ end<br />5’ end<br />Sugar-phosphatebackbone<br />Base pair (joined byhydrogen bonding)<br />Old strands<br />N...
64<br />A,T,C,G<br />The nitrogenous bases in DNA<br />Form hydrogen bonds in a complementary fashion (A with T only, and ...
05  macromolecules
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Carbohydrates, Proteins, Nucleic Acids, and Lipids (Enzymatic Action)

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05 macromolecules

  1. 1. 1<br />Carbon and the Molecular Diversity of Life<br />
  2. 2. 2<br />Figure 4.1<br />Carbon Chemistry<br />Carbon is the Backbone of Biological Molecules (macromolecules)<br />All living organisms Are made up of chemicals based mostly on the element carbon<br />
  3. 3. 3<br />Ball-and-Stick Model<br />Name and Comments<br />Space-Filling Model<br />Molecular Formula<br />Structural Formula<br />H<br />(a) Methane<br />CH4<br />C<br />H<br />H<br />H<br />H<br />H<br />(b) Ethane<br />C2H6<br />C<br />H<br />H<br />C<br />H<br />H<br />H<br />H<br />(c) Ethene (ethylene)<br />C<br />C<br />C2H4<br />H<br />H<br />Figure 4.3 A-C<br />Carbon Chemistry<br />Organic chemistry is the study of carbon compounds<br />Carbon has four valence electrons and may form single, double, triple, or quadruple bonds<br />
  4. 4. 4<br />H<br />H<br />C<br />C<br />C<br />C<br />H<br />H<br />C<br />H<br />H<br />H<br />H<br />H<br />H<br />C<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />(a) Length<br />H<br />Ethane<br />Propane<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />H<br />H<br />H<br />H<br />(b) Branching<br />Butane<br />isobutane<br />H<br />H<br />H<br />H<br />C<br />H<br />(c) Double bonds<br />H<br />H<br />C<br />C<br />C<br />H<br />H<br />C<br />C<br />H<br />H<br />C<br />C<br />1-Butene<br />2-Butene<br />H<br />H<br />C<br />C<br />C<br />(d) Rings<br />Figure 4.5 A-D<br />Cyclohexane<br />Benzene<br />Carbon may bond to itself forming carbon chains<br />Carbon chains form the skeletons of most organic molecules<br />Carbon chains vary in length and shape<br />
  5. 5. 5<br />Fat droplets (stained red)<br />100 µm<br />(b) Mammalian adipose cells<br />(a) A fat molecule<br />Figure 4.6 A, B<br />Hydrocarbons<br />Hydrocarbons are molecules consisting of only carbon and hydrogen<br />Hydrocarbons Are found in many of a cell’s organic molecules<br />
  6. 6. 6<br />H<br />H<br />H<br />C<br />H<br />H<br />C<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />(a) Structural isomers<br />H<br />C<br />C<br />C<br />C<br />C<br />H<br />H<br />H<br />C<br />C<br />C<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />X<br />X<br />X<br />C<br />C<br />C<br />C<br />(b) Geometric isomers<br />X<br />H<br />H<br />H<br />CO2H<br />CO2H<br />C<br />C<br />(c) Enantiomers<br />H<br />H<br />NH2<br />NH2<br />CH3<br />CH3<br />Figure 4.7 A-C<br />Isomers<br />Isomers are molecules with the same molecular formula but different structures and properties<br />Three types of isomers are<br />Structural<br />Geometric<br />Enantiomers<br />
  7. 7. 7<br />L-Dopa<br />(effective against Parkinson’s disease)<br />D-Dopa<br />(biologically inactive)<br />Figure 4.8<br />Enantiomers Are important in the pharmaceutical industry<br />
  8. 8. 8<br />OH<br />CH3<br />Estradiol<br />HO<br />Female lion<br />OH<br />CH3<br />CH3<br />O<br />Testosterone<br />Male lion<br />Figure 4.9<br />Functional Groups<br />Functional groups are the parts of molecules involved in chemical reactions<br />They Are the chemically reactive groups of atoms within an organic molecule<br />Give organic molecules distinctive chemical properties<br />
  9. 9. 9<br />Six functional groups are important in the chemistry of life<br />Hydroxyl<br />Carbonyl<br />Carboxyl<br />Amino<br />Sulfhydryl<br />Phosphate<br />
  10. 10. 10<br />FUNCTIONAL<br />GROUP<br /> HYDROXYL CARBONYL CARBOXYL<br />O<br />O<br />OH<br />C<br />C<br />OH<br />(may be written HO )<br />In a hydroxyl group (—OH), a hydrogen atom is bonded to an oxygen atom, which in turn is bonded to the carbon skeleton of the organic molecule. (Do not confuse this functional group with the hydroxide ion, OH–.)<br />STRUCTURE<br />The carbonyl group( CO) consists of a carbon atom joined to an oxygen atom by a double bond.<br />When an oxygen atom is double-bonded to a carbon atom that is also bonded to a hydroxyl group, the entire assembly of atoms is called a carboxyl group (—COOH).<br /><br />Figure 4.10<br />Some important functional groups of organic compounds<br />
  11. 11. 11<br />Ketones if the carbonyl group is within a carbon skeleton <br />Aldehydes if the carbonyl group is at the end of the carbon skeleton<br />NAME OF COMPOUNDS<br />Alcohols (their specific names usually end in -ol)<br />Carboxylic acids, or organic acids<br />EXAMPLE<br />H<br />H<br />H<br />H<br />O<br />O<br />C<br />C<br />H<br />OH<br />C<br />C<br />H<br />C<br />H<br />C<br />H<br />OH<br />H<br />H<br />H<br />H<br />C<br />Ethanol, the alcohol present in alcoholic beverages<br />H<br />H<br />Acetic acid, which gives vinegar its sour tatste<br />Acetone, the simplest ketone<br />H<br />H<br />O<br />C<br />C<br />C<br />H<br />H<br />H<br />H<br />Propanal, an aldehyde<br />Figure 4.10<br />Some important functional groups of organic compounds<br />
  12. 12. 12<br /> AMINO SULFHYDRYL PHOSPHATE<br />O<br />H<br />SH<br />N<br />P<br />OH<br />O<br />(may be written HS )<br />H<br />OH<br />In a phosphate group, a phosphorus atom is bonded to four oxygen atoms; one oxygen is bonded to the carbon skeleton; two oxygens carry negative charges; abbreviated P . The phosphate group (—OPO32–) is an ionized form of a phosphoric acid group (—OPO3H2; note the two hydrogens).<br />The amino group (—NH2) consists of a nitrogen atom bonded to two hydrogen atoms and to the carbon skeleton.<br />The sulfhydryl group consists of a sulfur atom bonded to an atom of hydrogen; resembles a hydroxyl group in shape.<br />Figure 4.10<br />Some important functional groups of organic compounds<br />
  13. 13. 13<br />Macromolecules<br />Most macromolecules are polymers, built from monomers<br /> Four classes of life’s organic molecules are polymers<br />Carbohydrates<br />Proteins<br />Nucleic acids<br />Lipids<br />
  14. 14. 14<br />Carbohydrates<br />Serve as fuel and building material<br />Include both sugars and their polymers (starch, cellulose, etc.)<br />
  15. 15. 15<br />The Synthesis and Breakdown of Polymers<br />1<br />HO<br />H<br />3<br />2<br />HO<br />H<br />Unlinked monomer<br />Short polymer<br />Dehydration removes a watermolecule, forming a new bond<br />H2O<br />1<br />2<br />3<br />4<br />HO<br />H<br />Longer polymer<br />(a) Dehydration reaction in the synthesis of a polymer<br />Figure 5.2A<br />Monomers form larger molecules by condensation reactions called dehydration synthesis<br />
  16. 16. 16<br />The Synthesis and Breakdown of Polymers<br />1<br />3<br />HO<br />4<br />2<br />H<br />Hydrolysis adds a watermolecule, breaking a bond<br />H2O<br />1<br />2<br />H<br />HO<br />3<br />H<br />HO<br />(b) Hydrolysis of a polymer<br />Figure 5.2B<br />Polymers can disassemble by<br />Hydrolysis (addition of water molecules)<br />
  17. 17. 17<br />Triose sugars(C3H6O3)<br />Pentose sugars(C5H10O5)<br />Hexose sugars(C6H12O6)<br />H<br />H<br />H<br />H<br />O<br />O<br />O<br />O<br />C<br />C<br />C<br />C<br />H C OH<br />H C OH<br />H C OH<br />H C OH<br />H C OH<br />H C OH<br />HO C H<br />HO C H<br />Aldoses<br />H<br />H C OH<br />H C OH<br />HO C H<br />H C OH<br />H C OH<br />H C OH<br />Glyceraldehyde<br />H C OH<br />H C OH<br />H<br />Ribose<br />H<br />H<br />Glucose<br />Galactose<br />H<br />H<br />H<br />H C OH<br />H C OH<br />H C OH<br />C O<br />C O<br />C O<br />HO C H<br />H C OH<br />H C OH<br />Ketoses<br />H C OH<br />H C OH<br />H<br />Dihydroxyacetone<br />H C OH<br />H C OH<br />H C OH<br />H<br />Ribulose<br />H<br />Figure 5.3<br />Fructose<br />Examples of monosaccharides<br />
  18. 18. 18<br />Disaccharides<br />Consist of two monosaccharides<br />Dehydration Synthesis occurs (glycosidic linkage)<br />
  19. 19. 19<br />(a)<br />Dehydration reaction in the synthesis of maltose. The bonding of two glucose units forms maltose. The glycosidic link joins the number 1 carbon of one glucose to the number 4 carbon of the second glucose. Joining the glucose monomers in a different way would result in a different disaccharide. <br />CH2OH<br />CH2OH<br />CH2OH<br />CH2OH<br />O<br />O<br />O<br />O<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />1–4glycosidiclinkage<br />HOH<br />HOH<br />HOH<br />HOH<br />4<br />1<br />H<br />H<br />H<br />H<br />OH<br />OH<br />O<br />H<br />OH<br />HO<br />HO<br />OH<br />O<br />H<br />H<br />H<br />H<br />OH<br />OH<br />OH<br />OH<br />H2O<br />Glucose<br />Maltose<br />Glucose<br />CH2OH<br />CH2OH<br />CH2OH<br />CH2OH<br />O<br />O<br />O<br />O<br />1–2glycosidiclinkage<br />H<br />H<br />H<br />H<br />H<br />HOH<br />HOH<br />H<br />2<br />1<br />H<br />OH<br />H<br />HO<br />H<br />HO<br />H<br />Dehydration reaction in the synthesis of sucrose. Sucrose is a disaccharide formed from glucose and fructose.Notice that fructose,though a hexose like glucose, forms a five-sided ring.<br />(b)<br />HO<br />H<br />O<br />O<br />HO<br />CH2OH<br />CH2OH<br />OH<br />H<br />H<br />OH<br />H<br />H<br />OH<br />OH<br />H2O<br />Glucose<br />Sucrose<br />Fructose<br />Figure 5.5<br />
  20. 20. 20<br />Polysaccharides<br />Polysaccharides<br />Are polymers of sugars<br />Serve many roles in organisms<br />
  21. 21. 21<br />Storage Polysaccharides<br />Chloroplast<br />Starch<br />1 m<br />Amylose<br />Amylopectin<br />(a) Starch: a plant polysaccharide<br />Figure 5.6<br />Starch<br />Is a polymer consisting entirely of glucose monomers<br />Is the major storage form of glucose in plants<br />
  22. 22. 22<br />Giycogen granules<br />Mitochondria<br />0.5 m<br />Glycogen<br />(b) Glycogen: an animal polysaccharide<br />Figure 5.6<br />Glycogen<br />Consists of glucose monomers<br />Is the major storage form of glucose in animals<br />
  23. 23. 23<br />Structural Polysaccharides<br />H<br />O<br />CH2OH<br />C<br />CH2OH<br />OH<br />OH<br />H<br />C<br />H<br />O<br />O<br />H<br />H<br />H<br />H<br />HO<br />OH<br />OH<br />C<br />H<br />4<br />4<br />1<br />H<br />H<br />HO<br />OH<br />HO<br />OH<br />H<br />C<br />H<br />OH<br />OH<br />H<br />OH<br />H<br />C<br />H<br />OH<br /> glucose<br />C<br /> glucose<br />H<br />(a)  and  glucose ring structures<br />CH2OH<br />CH2OH<br />CH2OH<br />CH2OH<br />O<br />O<br />O<br />O<br />OH<br />OH<br />OH<br />OH<br />1<br />4<br />4<br />4<br />1<br />1<br />1<br />HO<br />O<br />O<br />O<br />O<br />OH<br />OH<br />OH<br />OH<br />(b) Starch: 1– 4 linkage of  glucose monomers<br />OH<br />CH2OH<br />OH<br />CH2OH<br />O<br />O<br />OH<br />OH<br />O<br />O<br />OH<br />OH<br />HO<br />OH<br />4<br />O<br />1<br />O<br />O<br />CH2OH<br />CH2OH<br />OH<br />OH<br />(c) Cellulose: 1– 4 linkage of  glucose monomers<br />Figure 5.7 A–C<br />Cellulose<br />Is a polymer of glucose<br />
  24. 24. 24<br />About 80 cellulose<br />molecules associate<br />to form a microfibril, the<br />main architectural unit<br />of the plant cell wall.<br />Cellulose microfibrils <br />in a plant cell wall<br />Microfibril<br />Cell walls<br /><br />0.5 m<br />Plant cells<br />OH<br />OH<br />CH2OH<br />CH2OH<br />O<br />O<br />O<br />O<br />OH<br />OH<br />OH<br />OH<br />O<br />O<br />O<br />O<br />O<br />OH<br />CH2OH<br />CH2OH<br />OH<br />Cellulose<br />molecules<br />CH2OH<br />CH2OH<br />OH<br />OH<br />O<br />O<br />O<br />O<br />OH<br />OH<br />OH<br />OH<br />Parallel cellulose molecules are<br />held together by hydrogen<br />bonds between hydroxyl<br />groups attached to carbon<br />atoms 3 and 6.<br />O<br />O<br />O<br />O<br />O<br />OH<br />CH2OH<br />OH<br />CH2OH<br />CH2OH<br />CH2OH<br />OH<br />OH<br />O<br />O<br />O<br />O<br />OH<br />OH<br />OH<br />OH<br />O<br />O<br />O<br />A cellulose molecule<br />is an unbranched <br />glucose polymer.<br />O<br />O<br />OH<br />CH2OH<br />OH<br />CH2OH<br />Figure 5.8<br /><ul><li>Glucose monomer</li></ul>Is a major component of the tough walls that enclose plant cells<br />
  25. 25. 25<br />CH2OH<br />O<br />OH<br />H<br />H<br />OH<br />H<br />H<br />H<br />NH<br />O<br />C<br />CH3<br />OH<br />(b) Chitin forms the exoskeleton <br />of arthropods. This cicada <br />is molting, shedding its old <br />exoskeleton and emerging<br />in adult form. <br />(c) Chitin is used to make a <br /> strong and flexible surgical<br /> thread that decomposes after<br /> the wound or incision heals.<br />(a) The structure of the<br /> chitin monomer.<br />Figure 5.10 A–C<br />Chitin, another important structural polysaccharide<br />Is found in the exoskeleton of arthropods<br />Can be used as surgical thread<br />
  26. 26. 26<br />Lipids<br />Lipids are a diverse group of hydrophobic molecules<br />Lipids<br />Are the one class of large biological molecules that do not consist of polymers<br />Share the common trait of being hydrophobic<br />
  27. 27. 27<br />Fats<br />Are constructed from two types of smaller molecules, a single glycerol and usually three fatty acids<br />Vary in the length and number and locations of double bonds they contain<br />
  28. 28. 28<br />Stearic acid<br />Figure 5.12<br />(a) Saturated fat and fatty acid<br />Saturated fatty acids<br />Have the maximum number of hydrogen atoms possible<br />Have no double bonds<br />
  29. 29. 29<br />Oleic acid<br />cis double bond<br />causes bending<br />Figure 5.12<br />(b) Unsaturated fat and fatty acid<br />Unsaturated fatty acids<br />Have one or more double bonds<br />
  30. 30. 30<br />+<br />CH2<br />Choline<br />N(CH3)3<br />CH2<br />O<br />Phosphate<br />Hydrophilic head<br />–<br />P<br />O<br />O<br />O<br />CH2<br />CH<br />CH2<br />Glycerol<br />O<br />O<br />C<br />O<br />C<br />O<br />Fatty acids<br />Hydrophilic<br />head<br />Hydrophobic tails<br />Hydrophobic<br />tails <br />(c) Phospholipid <br />symbol<br />(b) Space-filling model<br />Figure 5.13 <br />(a) Structural formula<br />Phospholipid structure<br />Consists of a hydrophilic “head” and hydrophobic “tails”<br />
  31. 31. 31<br />WATER<br />Hydrophilic<br />head <br />WATER<br />Hydrophobic<br />tail <br />Figure 5.14<br />The structure of phospholipids<br />Results in a bilayer arrangement found in cell membranes<br />
  32. 32. 32<br />H3C<br />CH3<br />CH3<br />CH3<br />CH3<br />HO<br />Figure 5.15<br />Steroids<br />One steroid, cholesterol<br />Is found in cell membranes<br />Is a precursor for some hormones<br />Steroids<br />Are lipids characterized by a carbon skeleton consisting of four fused rings<br />
  33. 33. 33<br />Proteins<br />Proteins have many structures, resulting in a wide range of functions<br />Proteins do most of the work in cells and act as enzymes<br />Proteins are made of monomers called amino acids<br />
  34. 34. 34<br />Table 5.1<br />An overview of protein functions<br />
  35. 35. 35<br />Substrate binds to<br />enzyme. <br />1 Active site is available for<br /> a molecule of substrate, the<br />reactant on which the enzyme acts.<br />2<br />2<br />Substrate<br />(sucrose) <br />Glucose<br />Enzyme <br />(sucrase) <br />OH<br />H2O<br />Fructose<br />H O<br />4 Products are released.<br />3 Substrate is converted<br />to products. <br />Figure 5.16<br />Enzymes<br />Are a type of protein that acts as a catalyst, speeding up chemical reactions<br />
  36. 36. 36<br />Polypeptides<br />Polypeptides<br />Are polymers (chains) of amino acids<br />A protein<br />Consists of one or more polypeptides<br />
  37. 37. 37<br />Amino acids<br />Are organic molecules possessing both carboxyl and amino groups<br />Differ in their properties due to differing side chains, called R groups<br />
  38. 38. 38<br />Twenty Amino Acids<br />CH3<br />CH3<br />CH3<br />CH<br />CH2<br />CH3<br />CH3<br />H<br />CH3<br />H3C<br />CH3<br />CH2<br />CH<br />O<br />O<br />O<br />O<br />O <br />H3N+<br />H3N+<br />H3N+<br />H3N+<br />C<br />H3N+<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />O–<br />O–<br />O–<br />O–<br />O–<br />H<br />H<br />H<br />H<br />H<br />Valine (Val)<br />Leucine (Leu)<br />Isoleucine (Ile)<br />Glycine (Gly)<br />Alanine (Ala)<br />Nonpolar<br />CH3<br />CH2<br />S<br />H2C<br />CH2<br />O<br />NH<br />CH2<br />H2N<br />C<br />C<br />CH2<br />O–<br />CH2<br />CH2<br />O<br />O<br />O<br />H<br />H3N+<br />H3N+<br />C<br />C<br />C<br />C<br />H3N+<br />C<br />C<br />O–<br />O–<br />O–<br />H<br />H<br />H<br />Phenylalanine (Phe)<br />Proline (Pro)<br />Methionine (Met)<br />Tryptophan (Trp)<br />Figure 5.17<br />20 different amino acids make up proteins<br />
  39. 39. 39<br />OH<br />NH2<br />O<br />C<br />NH2<br />O<br />C<br />OH<br />SH<br />CH2<br />CH3<br />OH<br />Polar<br />CH2<br />CH<br />CH2<br />CH2<br />CH2<br />CH2<br />O<br />O<br />O<br />O<br />O<br />O<br />H3N+<br />H3N+<br />H3N+<br />H3N+<br />H3N+<br />H3N+<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />O–<br />O–<br />O–<br />O–<br />O–<br />O–<br />H<br />H<br />H<br />H<br />H<br />H<br />Glutamine<br />(Gln)<br />Tyrosine<br />(Tyr)<br />Asparagine<br />(Asn)<br />Cysteine <br />(Cys)<br />Serine (Ser)<br />Threonine (Thr)<br />Basic<br />Acidic<br />NH3+<br />NH2<br />NH+<br />O–<br />O<br />–O<br />O<br />CH2<br />C<br />NH2+<br />C<br />C<br />NH<br />Electrically<br />charged <br />CH2<br />CH2<br />CH2<br />CH2<br />CH2<br />O<br />O<br />H3N+<br />H3N+<br />CH2<br />CH2<br />C<br />CH2<br />C<br />C<br />C<br />O<br />O–<br />H3N+<br />O–<br />CH2<br />C<br />CH2<br />C<br />H<br />O<br />H<br />H3N+<br />O–<br />C<br />C<br />CH2<br />H<br />O<br />O–<br />H3N+<br />C<br />C<br />H<br />O–<br />H<br />Lysine (Lys)<br />Histidine (His)<br />Arginine (Arg)<br />Glutamic acid <br />(Glu)<br />Aspartic acid <br />(Asp)<br />
  40. 40. 40<br />Amino Acid Polymers<br />Amino acids<br />Are linked by peptide bonds<br />
  41. 41. 41<br />Protein Conformation and Function<br />A protein’s specific conformation (shape) determines how it functions<br />
  42. 42. 42<br />Four Levels of Protein Structure<br />Amino acid subunits<br />+H3NAmino end<br />Pro<br />Thr<br />Gly<br />Gly<br />Thr<br />Gly<br />Glu<br />Seu<br />Lys<br />Cys<br />Pro<br />Leu<br />Met<br />Val<br />Lys<br />Val<br />Leu<br />Asp<br />Ala<br />Arg<br />Val<br />Gly<br />Ser<br />Pro<br />Ala<br />Glu<br />Lle<br />Asp<br />Thr<br />Lys<br />Ser<br />Tyr<br />Trp<br />Lys<br />Ala<br />Leu<br />Gly<br />lle<br />Ser<br />Pro<br />Phe<br />His<br />Glu<br />His<br />Ala<br />Glu<br />Val<br />Thr<br />Val<br />Phe<br />Ala<br />Asn<br />lle<br />Thr<br />Asp<br />Ala<br />Tyr<br />Arg<br />Ser<br />Ala<br />Arg<br />Pro<br />Gly<br />Leu<br />Leu<br />Ser<br />Pro<br />Tyr<br />Ser<br />Tyr<br />Ser<br />Thr<br />Thr<br />Ala<br />o<br />Val<br />c<br />Val<br />Glu<br />–<br />Lys<br />o<br />Thr<br />Pro<br />Asn<br />Carboxyl end<br />Figure 5.20<br />Primary structure<br />Is the unique sequence of amino acids in a polypeptide<br />
  43. 43. 43<br />H<br />H<br />H<br />H<br />H<br />H<br />O<br />O<br />O<br />O<br />O<br />O<br />O<br />H<br />H<br />H<br />H<br />H<br />H<br />R<br />R<br />R<br />R<br />R<br />R<br />R<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />N<br />N<br />N<br />N<br />N<br />N<br />N<br />N<br />N<br />N<br />N<br />N<br />N<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />C<br />R<br />R<br />R<br />R<br />R<br />R<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br />O<br />O<br />O<br />O<br />O<br />O<br />O<br />H<br />H<br />H<br />H<br />H<br />H<br />H<br /> pleated sheet<br />H<br />O<br />H<br />H<br />Amino acidsubunits<br />C<br />C<br />N<br />N<br />N<br />C<br />C<br />C<br />R<br />H<br />O<br />H<br />H<br />H<br />H<br />H<br />H<br />N<br />N<br />N<br />N<br />N<br />N<br /> helix<br />C<br />C<br />O<br />C<br />H<br />H<br />H<br />C<br />C<br />C<br />R<br />R<br />R<br />R<br />R<br />H<br />H<br />C<br />C<br />C<br />C<br />C<br />C<br />O<br />O<br />O<br />O<br />H<br />C<br />R<br />O<br />C<br />C<br />O<br />H<br />C<br />O<br />N<br />N<br />H<br />C<br />C<br />H<br />R<br />H<br />R<br />Figure 5.20<br />Secondary structure<br />Is the folding or coiling of the polypeptide into a repeating configuration<br />Includes the  helix and the  pleated sheet<br />
  44. 44. 44<br />Hydrophobic interactions and van der Waalsinteractions <br />CH<br />CH2<br />CH2<br />H3C<br />CH3<br />OH<br />Polypeptidebackbone<br />CH3<br />H3C<br />Hydrogenbond<br />CH<br />O<br />HO<br />C<br />CH2<br />S<br />S<br />CH2<br />CH2<br />Disulfide bridge<br />O<br />-O<br />C<br />CH2<br />CH2<br />NH3+<br />Ionic bond<br />Tertiary structure<br />Is the overall three-dimensional shape of a polypeptide<br />Results from interactions between amino acids and R groups<br />
  45. 45. 45<br />Polypeptidechain<br />Collagen<br /> Chains<br />Iron<br />Heme<br /> Chains<br />Hemoglobin<br />Quaternary structure<br />Is the overall protein structure that results from the aggregation of two or more polypeptide subunits<br />
  46. 46. 46<br />Review of Protein Structure<br />+H3N<br />Amino end<br />Amino acid<br />subunits<br />helix<br />
  47. 47. 47<br />Sickle-Cell Disease: A Simple Change in Primary Structure<br />Sickle-cell disease<br />Results from a single amino acid substitution in the protein hemoglobin<br />
  48. 48. 48<br />Normal hemoglobin<br />Sickle-cell hemoglobin<br />Primary structure<br />Primary structure<br />. . .<br />. . .<br />Exposed hydrophobic region<br />Val<br />Thr<br />His<br />Leu<br />Pro<br />Glul<br />Glu<br />Val<br />His<br />Leu<br />Pro<br />Glu<br />Thr<br />Val<br />5<br />6<br />7<br />3<br />4<br />5<br />6<br />7<br />2<br />1<br />1<br />2<br />3<br />4<br />Secondaryand tertiarystructures<br />Secondaryand tertiarystructures<br /> subunit<br /> subunit<br /><br /><br /><br /><br />Quaternary structure<br />Hemoglobin A<br />Quaternary structure<br />Hemoglobin S<br /><br /><br /><br /><br />Molecules interact with one another tocrystallize into a fiber, capacity to carry oxygen is greatly reduced.<br />Function<br />Molecules donot associatewith oneanother, eachcarries oxygen.<br />Function<br />10 m<br />10 m<br />Normal cells arefull of individualhemoglobinmolecules, eachcarrying oxygen<br />Red bloodcell shape<br />Red bloodcell shape<br />Figure 5.21<br />Fibers of abnormalhemoglobin deform cell into sickle shape.<br />
  49. 49. 49<br />What Determines Protein Conformation?<br />Protein conformation Depends on the physical and chemical conditions of the protein’s environment<br />Temperature, pH, etc. affect protein structure<br />
  50. 50. 50<br />Denaturation<br />Denatured protein<br />Normal protein<br />Renaturation<br />Figure 5.22<br /><ul><li>Denaturation is when a protein unravels and loses its native conformation(shape)</li></li></ul><li>51<br />The Protein-Folding Problem<br />Most proteins<br />Probably go through several intermediate states on their way to a stable conformation <br />Denaturated proteins no longer work in their unfolded condition<br />Proteins may be denaturated by extreme changes in pH or temperature<br />
  51. 51. 52<br />Correctlyfoldedprotein<br />Polypeptide<br />Cap<br />Hollowcylinder<br /> The cap attaches, causing the cylinder to change shape insuch a way that it creates a hydrophilic environment for the folding of the polypeptide. <br /> The cap comesoff, and the properlyfolded protein is released.<br />Steps of ChaperoninAction: An unfolded poly- peptide enters the cylinder from one end. <br />Chaperonin(fully assembled)<br />2<br />1<br />3<br />Figure 5.23<br />Chaperonins<br />Are protein molecules that assist in the proper folding of other proteins<br />
  52. 52. 53<br />Nucleic Acids<br />Nucleic acids store and transmit hereditary information<br />Genes<br />Are the units of inheritance<br />Program the amino acid sequence of polypeptides<br />Are made of nucleotide sequences on DNA<br />
  53. 53. 54<br />The Roles of Nucleic Acids<br />There are two types of nucleic acids<br />Deoxyribonucleic acid (DNA)<br />Ribonucleic acid (RNA)<br />
  54. 54. 55<br />Deoxyribonucleic Acid<br />DNA<br />Stores information for the synthesis of specific proteins<br />Found in the nucleus of cells<br />
  55. 55. 56<br />DNA<br />1<br /> Synthesis of mRNA in the nucleus<br />mRNA<br />NUCLEUS<br />CYTOPLASM<br />mRNA<br />2<br />Movement of <br />mRNA into cytoplasm <br /> via nuclear pore<br />Ribosome<br />3<br />Synthesis<br />of protein<br />Aminoacids<br />Polypeptide<br />Figure 5.25<br />DNA Functions<br />Directs RNA synthesis (transcription)<br />Directs protein synthesis through RNA (translation)<br />
  56. 56. 57<br />5’ end<br />5’C<br />O<br />3’C<br />O<br />O<br />5’C<br />O<br />3’C<br />3’ end<br />OH<br />Figure 5.26 <br />The Structure of Nucleic Acids<br />Nucleic acids<br />Exist as polymers called polynucleotides<br />(a) Polynucleotide, <br />or nucleic acid<br />
  57. 57. 58<br />Nucleoside<br />Nitrogenous<br />base<br />O<br />5’C<br />O<br />O<br />CH2<br />P<br />O<br />O<br />Phosphate<br />group<br />3’C<br />Pentose<br />sugar<br />Figure 5.26 <br />(b) Nucleotide<br />Each polynucleotide<br />Consists of monomers called nucleotides<br />Sugar + phosphate + nitrogen base<br />
  58. 58. 59<br />Nitrogenous bases Pyrimidines<br />NH2<br />O<br />O<br />C<br />C<br />CH3<br />C<br />N<br />CH<br />HN<br />C<br />CH<br />HN<br />CH<br />CH<br />CH<br />C<br />C<br />C<br />CH<br />CH<br />N<br />N<br />N<br />O<br />O<br />O<br />H<br />H<br />H<br />Uracil (in RNA)<br />U<br />Cytosine<br />C<br />Thymine (in DNA)<br />T<br />Uracil (in RNA)<br />U<br />Purines<br />O<br />NH2<br />C<br />C<br />N<br />N<br />C<br />C<br />NH<br />N<br />HC<br />HC<br />C<br />CH<br />C<br />N<br />N<br />NH2<br />N<br />N<br />H<br />H<br />Adenine<br />A<br />Guanine<br />G<br />Pentose sugars<br />5”<br />5”<br />OH<br />OH<br />HOCH2<br />HOCH2<br />O<br />O<br />H<br />H<br />H<br />H<br />1’<br />1’<br />4’<br />4’<br />H<br />H<br />H<br />H<br />3’<br />2’<br />3’<br />2’<br />H<br />OH<br />OH<br />OH<br />Deoxyribose (in DNA)<br />Ribose (in RNA)<br />Ribose (in RNA)<br />Nucleotide Monomers<br />Nucleotide monomers<br />Are made up of nucleosides (sugar + base) and phosphate groups<br />Figure 5.26 <br />(c) Nucleoside components<br />
  59. 59. 60<br />Nucleotide Polymers<br />Nucleotide polymers<br /> Are made up of nucleotides linked by the–OH group on the 3´ carbon of one nucleotide and the phosphate on the 5´ carbon on the next<br />
  60. 60. 61<br />Gene<br />The sequence of bases along a nucleotide polymer<br />Is unique for each gene<br />
  61. 61. 62<br />The DNA Double Helix<br />Cellular DNA molecules<br />Have two polynucleotides that spiral around an imaginary axis<br />Form a double helix<br />
  62. 62. 63<br />3’ end<br />5’ end<br />Sugar-phosphatebackbone<br />Base pair (joined byhydrogen bonding)<br />Old strands<br />Nucleotideabout to be added to a new strand<br />3’ end<br />A<br />5’ end<br />Newstrands <br />3’ end<br />3’ end<br />5’ end<br />Figure 5.27<br />The DNA double helix<br />Consists of two antiparallel nucleotide strands<br />
  63. 63. 64<br />A,T,C,G<br />The nitrogenous bases in DNA<br />Form hydrogen bonds in a complementary fashion (A with T only, and C with G only)<br />

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