Chapter 3 The Chemical Building Blocks of Life PDF

Chapter 3 The Chemical Building Blocks of Life © McGraw Hill, LLC 1  Lecture Outline 3.1 Carbon: The Framework of Biological Molecules 3.2 Carbohydrates: Energy Storage and...

Chapter 3 The Chemical Building Blocks of Life © McGraw Hill, LLC 1  Lecture Outline 3.1 Carbon: The Framework of Biological Molecules 3.2 Carbohydrates: Energy Storage and Structural Molecules 3.3 Nucleic Acids: Information Molecules 3.4 Proteins: Molecules with Diverse Structures and Functions 3.5 Lipids: Hydrophobic Molecules Deco/Alamy Stock Photo © McGraw Hill, LLC 2  Modern Biochemistry Modern biochemistry studies biological molecules outside of cells. Classes of biological macromolecules Carbohydrates Lipids Proteins Nucleic Acids © McGraw Hill, LLC 3  Carbon Framework of biological molecules consists primarily of carbon bonded to Carbon O, N, S, P or H. Can form up to four covalent bonds Hydrocarbons – molecule consisting only of carbon and hydrogen Nonpolar © McGraw Hill, LLC 4  Functional Groups Functional groups are specific molecular groups that bond to carbon-hydrogen cores Each group has unique chemical properties. Properties of functional groups are retained wherever they attach and influence behavior of entire molecule in reactions. © McGraw Hill, LLC 5  Examples of Functional Groups Figure 3.2 © McGraw Hill, LLC 6  Macromolecules Polymer – built by linking monomers Monomer – small, similar chemical subunits TABLE 3.1 Macromolecules Macromolecule Subunit Function Example CARBOHYDRATES Starch, glycogen Glucose Energy storage Potatoes Cellulose Glucose Structural support in plant cell walls Paper; strings of celery Chitin Modified glucose Structural support Crab shells NUCLEIC ACIDS DNA Nucleotides Encodes genes Chromosomes RNA Nucleotides Needed for gene expression Messenger RNA PROTEINS Functional Amino acids Catalysis; transport Hemoglobin Structural Amino acids Support Hair; silk LIPIDS Triglycerides Glycerol and three fatty acids Energy storage Butter; corn oil; soap (animal fat, oils) Phospholipids Glycerol, two fatty acids, phosphate, and Cell membranes Phosphatidylcholine polar R groups Prostaglandins Five-carbon rings with two nonpolar tails Chemical messengers Prostaglandin E (PG E) Steroids Four fused carbon rings Membranes; hormones Cholesterol; estrogen Terpenes Long carbon chains Pigments; structural support Carotene; rubber © McGraw Hill, LLC 7  Carbohydrates and Nucleic Acids Are Macromolecules Figure 3.4 Access the text alternative for slide images. © McGraw Hill, LLC 8  Proteins and Lipids Are Macromolecules Figure 3.4 Access the text alternative for slide images. © McGraw Hill, LLC 9  Assembly and Disassembly of Polymers Dehydration synthesis Formation of large molecules by the removal of water. Monomers are joined to form polymers. Hydrolysis Breakdown of large molecules by the addition of water. Polymers are broken down to monomers. Access the text alternative for slide images. © McGraw Hill, LLC 10  Carbohydrates Molecules with a 1:2:1 ratio C:H:O empirical formula (CH2O)n C—H covalent bonds hold much energy Carbohydrates are good energy storage molecules. Examples: sugars, starch, glucose. © McGraw Hill, LLC 11  Monosaccharides Simplest carbohydrate Sugars with six carbons play important roles Glucose C6H12O6 Fructose is a structural isomer of glucose Galactose is a stereoisomer of glucose Enzymes that act on different sugars can distinguish structural and stereoisomers of this basic six-carbon skeleton © McGraw Hill, LLC 12  3-Carbon, 5-Carbon, and 6-Carbon Sugars Figure 3.6 Access the text alternative for slide images. © McGraw Hill, LLC 13  Disaccharides Two monosaccharides linked together by dehydration synthesis Used for sugar transport or energy storage Examples: sucrose, lactose, maltose Access the text alternative for slide images. © McGraw Hill, LLC 14  Polysaccharides Long chains of monosaccharides Linked through dehydration synthesis. Energy storage Plants use starch. Animals use glycogen. Structural support OAR/National Undersea Research Program (NURP) Plants use cellulose in cell wall. Arthropods and fungi use chitin. © McGraw Hill, LLC 15  Starch and Glycogen Are Polysaccharides (b) Asa Thoresen/Science Source; (c) Mike Rosecope/Shutterstock Figure 3.10 Access the text alternative for slide images. © McGraw Hill, LLC 16  Cellulose Is a Polysaccharide in Plants (b) Martin Kreutz/age fotostock Figure 3.11 Access the text alternative for slide images. © McGraw Hill, LLC 17  Nucleic Acids Polymer − nucleic acids Monomers − nucleotides Sugar + phosphate + nitrogenous base. Sugar is deoxyribose in DN A or ribose in RNA. Nitrogenous bases include. Purines: adenine and guanine. Pyrimidines: thymine, cytosine, uracil. Nucleotides connect by (a) Driscoll, Youngquist & Baldeschwieler, California Institute of phosphodiester bonds. Technology/Science Source; (b) Molekuul/SPL/age fotostock Access the text alternative for slide images. © McGraw Hill, LLC 18  Nucleotide Structure Figure 3.14 Access the text alternative for slide images. © McGraw Hill, LLC 19  Nucleic Acid Structure Access the text alternative for slide images. © McGraw Hill, LLC 20  Deoxyribonucleic Acid (DNA) Encodes information for amino acid sequence of proteins Sequence of bases. Double helix – two polynucleotide strands connected by hydrogen bonds Base-pairing rules. A with T (or U in RNA). C with G. © McGraw Hill, LLC 21  Structure of DNA Figure 3.17 Access the text alternative for slide images. © McGraw Hill, LLC 22  Ribonucleic Acid (RNA) 3 RNA is similar to DNA except the nucleotides Contain ribose instead of deoxyribose. Include the base uracil instead of thymine. Single polynucleotide strand RNA uses information in DNA to specify sequence of amino acids in proteins © McGraw Hill, LLC 23  DNA Structure Versus RNA Structure Figure 3.18 Access the text alternative for slide images. © McGraw Hill, LLC 24  ATP, NAD+, and FAD Adenosine triphosphate (ATP) Primary energy currency of the cell. Nicotinamide adenine dinucleotide (NAD+) and flavin adenine dinucleotide (FAD) Electron carriers for many cellular reactions. Access the text alternative for slide images. © McGraw Hill, LLC 25  Protein Functions Protein functions include: 1. Enzyme catalysis 2. Defense 3. Transport 4. Support 5. Motion 6. Regulation 7. Storage © McGraw Hill, LLC 26  Protein Characteristics Proteins are polymers Composed of one or more long, unbranched chains. Each chain is a polypeptide. Amino acids are monomers Amino acid structure Central carbon atom. Amino group (NH2). Carboxyl group (COOH). Single hydrogen. Variable R group. Access the text alternative for slide images. © McGraw Hill, LLC 27  20 Common Amino Acids Figure 3.21 Access the text alternative for slide images. © McGraw Hill, LLC 28  Peptide Bonds Amino acids joined by dehydration synthesis Bond formed between the amino end and carboxyl end of two adjacent amino acids. © McGraw Hill, LLC Access the text alternative for slide images. 29  Four Levels of Protein Structure The shape of a protein determines its function 1. Primary structure − sequence of amino acids 2. Secondary structure − interaction of groups in the peptide backbone helix = coiled spiral. sheet = planar structure. © McGraw Hill, LLC 30  Four Levels of Structure 3. Tertiary structure – final folded shape of a globular protein Stabilized by a number of forces. Final level of structure for proteins consisting of only a single polypeptide chain. 4. Quaternary structure – arrangement of individual chains (subunits) in a protein with two or more polypeptide chains © McGraw Hill, LLC 31  Levels of Protein Structure Figure 3.22 Access the text alternative for slide images. © McGraw Hill, LLC 32  Interactions That Contribute to a Protein’s Shape Access the text alternative for slide images. © McGraw Hill, LLC 33  Denaturation Protein loses its structure by unfolding and then also its function Due to environmental conditions pH. Temperature. Ionic concentration of solution. © McGraw Hill, LLC 34  Lipids Loosely defined group of molecules with one main chemical characteristic They are insoluble in water. High proportion of nonpolar C—H bonds causes the molecule to be hydrophobic Fats, oils, waxes, terpenes, steroids, and even some vitamins © McGraw Hill, LLC 35  Fats Triglycerides Composed of 1 glycerol and 3 fatty acids. Fatty acids Need not be identical. Chain length varies. Saturated – no double bonds between carbon atoms. Higher melting point, animal origin. Unsaturated – one or more double bonds. Low melting point, plant origin. Trans fats produced industrially. © McGraw Hill, LLC 36  Structure of Saturated Versus Unsaturated Fat Figure 3.28 Access the text alternative for slide images. © McGraw Hill, LLC 37  Phospholipids Composed of Glycerol Two fatty acids – nonpolar “tails” A phosphate group – polar “head” Form all biological membranes © McGraw Hill, LLC 38  Phospholipid Structure Figure 3.30 Access the text alternative for slide images. © McGraw Hill, LLC 39  Micelles Micelles – lipid molecules orient with polar (hydrophilic) head toward water and nonpolar (hydrophobic) tails away from water Access the text alternative for slide images. © McGraw Hill, LLC 40  Phospholipid Bilayer Phospholipid bilayer – more complicated structure where two layers form Hydrophilic heads point outward. Hydrophobic tails point inward toward each other. Access the text alternative for slide images. © McGraw Hill, LLC 41 Because learning changes everything. ® www.mheducation.com © 2023 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC.