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Chapter 3 • Biological Molecules Copyright © 2005 Pearson Prentice Hall, Inc. Complex Carbohydrates - I • Monomer = Monosaccharides – Several with Slightly Different Structures • Hexoses: Glucose (F3.1 p. 40), Fructose, Galactose • Pentoses: Ribose, Deoxyribose Copyright © 2005 Pearson Prentice Hall, Inc. HOCH2 H O H HO H HO HO OH CH2OH HO CH2OH O H fructose OH H H H H OH galactose HOCH2 H O OH H H H H OH HOCH2 OH ribose O OH H H H OH H deoxyribose H H H 6 H 5 C O C H 4 O H C O 3 O H C H 2 H C 1 O H C H = O H H O H C C H C O H 6 H 5 O O H H 4 O H H 3 H C1 H C CH2OH glucose C = O 2 O H HO H H OH H H OH H OH Complex Carbohydrates - II • Polysaccharides Are Chains of Monosaccharides – – – – Starch: plant energy storage - glucose monomers (F3.3) Glycogen: animal energy storage Cellulose: plant structure & function (F3.4 p. 42) Chitin: animal structure - unique (F3.5 p. 43) Copyright © 2005 Pearson Prentice Hall, Inc. 100 micrometers masses of starch globules CH2OH CH2OH O O H H H H H H OH H OH H O H OH H OH O CH2OH CH2 CH2OH CH2OH O O O O H H H H H H H H H H H H OH H OH H O O OH H O OH H O H OH H OH H OH H OH wood is mostly cellulose plant cell with cell wall close-up of cell wall 1 micrometer CH2OH H OH O H OH HH OH O H H OH OH H H O O H CH2OH 1 micrometer H OH H H H H H O H OH O CH2OH H O H H OH H H O O CH2OH individual cellulose molecules bundle of cellulose fiber cellulose molecules CH3 CH3 O C O C CH2OH O H H OH H O H N H CH2OH H N H O H H H OH H OH H H O O OH H H H O O H H H H O O H N H H N H CH2OH CH2OH O C O C CH3 CH3 How Are Biological Polymers Synthesized & Broken Down? • Monomers Are Joined to Form Polymers by Removing Water – Dehydration synthesis (F 1 p. 39) • Monomers are Separated to Break Down the Polymer by Adding Water – Hydrolysis Copyright © 2005 Pearson Prentice Hall, Inc. (F 2 p. 39) glucose CH2OH O H H H HO OH H H sucrose fructose OH OH HOCH2 HO H OH O H HO H CH2OH O H H H Dehydration OH CH2 OH synthesis HO H HOCH2 O H OH H O O H H OH H HO H CH2OH O HO O H OH H Hydrolysis HO OH HO OH Lipids • Lipid Monomers are Glycerol & Fatty Acids – Triglyceride Synthesis (F 3.6 p. 43) • Dehydration Condensation – Oils, Fats, and Waxes Are Lipids • RT Solid Lipid = Saturated • RT Liquid Lipid = Unsaturated (F3.7 p. 44) (F 5 p. 44) (F 6 p. 44) – Phospholipids – Biological Membranes • Polar Head & Nonpolar Tail (F 3.8 p. 45) • Functional Groups on Biomolecules (T3.1) – Steroids – Membranes & Hormones • Four Carbon Rings Fused Together Copyright © 2005 Pearson Prentice Hall, Inc. (F 3.9 p. 46) etc. CH2 H H C OH H C OH H C OH H glycerol O CH HO C CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH CH2 CH2 O HO C CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 etc. O HO C CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 etc. fatty acids CH2 H O CH H C O C CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH CH2 etc. CH2 O H C O C CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 etc. O H C O C CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 etc. H triglyceride O H H O H H O H H 3 water molecules Fat Wax Beef fat (saturated) oleic acid Linseed oil (unsaturated) Lipids II - Phospholipids O CH3 H3 C-N-CH2-CH2-O-P-O-CH2 O O HC-O-C- CH2 -CH2-CH2-CH2 -CH2 -CH2-CH2-CH2 O CH3 CH CH - 2 CH2 CH2 CH2 CH2 CH2 CH2 CH3 2 H2C-O-C-CH2 -CH2-CH2-CH2 -CH2 -CH2-CH2-CH2-CH2 -CH2-CH2-CH2 -CH2 -CH2-CH2-CH3 polar head glycerol backbone fatty acid tails (hydrophobic) (hydrophilic) •Polar “Heads” Water-Soluble • Nonpolar “Tails” Water-Insoluble •(F 3.8 p. 45) OH CH3 CH3 HC CH3 CH2 CH2 HO estradiol CH2 HC CH3 CH3 OH CH3 CH3 CH3 HO O cholesterol testosterone Proteins - I • Polymer of Amino Acid Monomers AA structure (F7 p. 46) Joined by peptide bond (F3.12) form by dehydration synthesis broken by dehydration • Functions of Proteins • Structural proteins Copyright © 2005 Pearson Prentice Hall, Inc. (T3.3 p46) (p. 47) variable group R amino group H O N C H H hydrogen carboxylic acid group C O H amino acid amino group carboxyl group amino acid amino group carboxyl group peptide water peptide bond Hair Horn Silk Proteins - II • FUNCTION FOLLOWS FORM • Amino Acids Chains Are Folded into Distinct Forms in Space • Any Protein Has Three or Four Levels of Structure – Alzheimers Sickle Cell Disease – Four levels of protein structure • • • • Primary structure: Secondary structure: Tertiary Structure: Quaternary Structure: (F3.13 p. 49) amino acid sequence a-helix & pleated sheet (F3.14 p. 50) Location of Secondary Structure in Space Arrangement of 2 or more polypeptides • Due to Diverse Amino Acid Side Chains (F3.11p. 47) – Interact via Strong Covalent Disulfide Bridges & Weak Hydrogen Bonds Copyright © 2005 Pearson Prentice Hall, Inc. (F8p48) gly leu val leu val lys lys lys gly his lys gly ala lys val his lys pro ala lys val lys pro R R O C N C H R C C N N C C N C C O R N C H C C N N C C N C C O R O N C H O N C C N C C O R R C R O O R O C R O R O R Pleated sheet R O C N C C O R N C H C N C C O R R O R C C N N C C C O R polypeptide hydrogen bond Proteins - II • FUNCTION FOLLOWS FORM • Amino Acids Chains Are Folded into Distinct Forms in Space • Any Protein Has Three or Four Levels of Structure – Alzheimers Sickle Cell Disease – Four levels of protein structure Protein Fold Animation Ch 3\3_2_7a.swf Mage_5_79_001120.exe • • • • Primary structure: Secondary structure: Tertiary Structure: Quaternary Structure: (F3.13 p. 49) amino acid sequence a-helix & pleated sheet (F3.14 p. 50) Location of Secondary Structure in Space Arrangement of 2 or more polypeptides • Due to Diverse Amino Acid Side Chains (F3.11p. 47) – Interact via Strong Covalent Disulfide Bridges & Weak Hydrogen Bonds Copyright © 2005 Pearson Prentice Hall, Inc. (F8p48) hydrophilic NH2 C NH NH O H2N OH C CH2 CH2 CH2 CH2 CH2 C C OH H2N H O glutamic acid (glu) C C H O OH arginine (arg) hydrophobic CH3 CH3 CH CH2 CH2 H2N C C OH H2N H O phenylalanine (phe) forms disulfide bridges C C OH H O leucine (leu) SH CH2 H2N C C OH H O cysteine (cys) s s s-s s-s s s s-s keratin s s Nucleic Acids • Nucleic Acids: Polymers of Nucleotide Monomers – DNA and RNA, Molecules of Heredity – Monomers: deoxynucleotides – DNA ribonucleotides - RNA (F9) – Other Functions of Nucleotides • Intracellular Messengers, Energy Carriers, Coenzymes (F3.15 p. 51) Copyright © 2005 Pearson Prentice Hall, Inc. base NH2 phosphate N C C OH HO P N HC O O CH O N C sugar H H H H OH H Deoxyribose nucleotide N CH phosphate base sugar Nucleotide chain Vitamin NH2 N C C NH2 N HC CH2 H H O P O OH O HO H H N N C CH HC N C N CH O O N C C P O OH O P O OH O P O O CH2 NH2 P O H H OH CH2 O H H OH OH Cyclic adenosine monophosphate (cyclic AMP) (intracellular communication) Adenosine triphosphate (ATP) (energy carrier) N C C N N C CH HC O OH OH P O O HO O H H N HO H H OH Coenzyme (active in cellular metabolism) N