Essentials of Biology Chapter 3: The Organic Molecules of Life PDF

9/13/2023 Because learning changes everything. ® Chapter 3 The Organic Molecules of Life Essentials of Biology SEVENTH EDITION Sylvia S. Mader Mich...

9/13/2023 Because learning changes everything. ® Chapter 3 The Organic Molecules of Life Essentials of Biology SEVENTH EDITION Sylvia S. Mader Michael Windelspecht © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 3.1 Organic Molecules Organic chemistry – study of organic molecules Organic molecules contain carbon and hydrogen. Inorganic molecules do not contain a combination of carbon and hydrogen (H2O and NaCl). The diversity and functions of organic molecules in cells are biological molecules / biomolecules Biological molecules – carbohydrate, lipid, protein, or nucleic acid. © McGraw Hill LLC 2 Figure 3.1 Organic Molecules Have a Variety of Functions Access the text alternative for slide images. © McGraw Hill LLC (a): SuperStock/Alamy Stock Photo; (b): James Archer/CDC; (c): Zeljko Radojko/iStock/Getty Images; (d): Adrian T Sumner/Science Source 3 1  9/13/2023 The Carbon Atom 1 Carbon atom: Total of six electrons—four in outer shell Almost always shares electrons with elements such as hydrogen, nitrogen, and oxygen Can bond with as many as four other elements Most often shares electrons with other carbon atoms Hydrocarbons—chains of carbon atoms bonded only to hydrogen atoms © McGraw Hill LLC 4 Figure 3.2 Hydrocarbons Are Highly Versatile Access the text alternative for slide images. © McGraw Hill LLC 5 The Carbon Atom 2 Isomers—same number and kinds of atoms in a variety of arrangements May have different properties Glucose can be broken down anywhere in the body; Galactose and Fructose only in the liver © McGraw Hill LLC 6 2  9/13/2023 The Carbon Atom 3 Carbon skeleton – carbon chain of organic molecule Size and shape of carbon skeleton or backbone accounts for size of organic molecule Reactivity of organic molecule largely dependent on attached functional groups Functional group—specific combination of bonded atoms that always has the same chemical properties and always reacts the same way Often use R to stand for the remainder of the molecule © McGraw Hill LLC 7 Figure 3.3 Common Functional Groups Access the text alternative for slide images. © McGraw Hill LLC 8 3.2 Carbohydrates and Lipids There are four categories of biological molecules Carbohydrates Lipids Proteins Nucleic Acids Digestion breaks these molecules into subunits to build the macromolecules that make up the body. © McGraw Hill LLC 9 3  9/13/2023 Building Complex Biological Molecules Monomers—subunits Polymer—monomers joined together Dehydration synthesis reaction Joins monomers to form polymers; equivalent of removing a water molecule Hydrolysis Reaction OH group attaches to one monomer and H from water attaches to the other monomer; used to break bonds in a polymer. © McGraw Hill LLC 10 Figure 3.4 Synthesis and Breakdown of Polymers Access the text alternative for slide images. © McGraw Hill LLC 11 Carbohydrates 1 Carbohydrates are mainly used for immediate energy source. May also be used for structural component Carbohydrates are classified as monosaccharides disaccharides polysaccharides © McGraw Hill LLC 12 4  9/13/2023 Figure 3.5 Carbohydrates © McGraw Hill LLC John Thoeming/McGraw Hill 13 Carbohydrates 2 Monosaccharides: Single sugar molecule Simple sugars Three to seven carbon backbone Glucose C6H12O6 Two isomers—fructose and galactose Cells use glucose as the energy source of choice. Ribose and deoxyribose (5 C atoms) are found in RNA and DNA. © McGraw Hill LLC 14 Figure 3.6 Glucose Access the text alternative for slide images. © McGraw Hill LLC 15 5  9/13/2023 Disaccharides Disaccharides: Two monosaccharides bonded together Maltose—yeast breaks down maltose in beer for energy and produces ethyl alcohol. Fermentation Sucrose—table sugar Broken down into glucose and fructose Glucose is used immediately, fructose is converted to glucose as needed or stored as fat © McGraw Hill LLC 16 Figure 3.7 Converting Maltose to Ethanol Access the text alternative for slide images. © McGraw Hill LLC 17 Polysaccharides Many polysaccharides are used as short-term energy storage molecules. Polymers of monosaccharides Some function as energy storage molecules. Plants store glucose as starch. Animals store glucose as glycogen. Some function as structural components. Cellulose—plant cell walls Most abundant of all organic molecules Digested only by some microbes Chitin—crab, lobster, insect exoskeletons © McGraw Hill LLC 18 6  9/13/2023 Figure 3.8 Starch and Glycogen Structure and Function Access the text alternative for slide images. © McGraw Hill LLC (photos): (a): Dr. Jeremy Burgess/Science Source; (b): Don W. Fawcett/Science Source 19 Figure 3.9 Cellulose Structure and Function Access the text alternative for slide images. © McGraw Hill LLC (photo): Cheryl Power/Science Source 20 Lipids Lipids: All are insoluble in water. Long nonpolar hydrocarbon chains Relative lack of hydrophilic functional groups Very diverse structures and functions Fats and oils used for long-term energy storage. Oil may help waterproof skin, hair, and feathers. © McGraw Hill LLC 21 7  9/13/2023 Figure 3.10 Lipid Foods © McGraw Hill LLC John Thoeming/McGraw Hill 22 Fats and Oils: Long-Term Energy Storage Fats and oils are made up of molecules called triglycerides which contain two subunit molecules: Glycerol—three carbon chain that has three –OH groups Fatty acid—a long chain of carbon atoms bonded only to hydrogen, with a carboxyl group at one end A triglyceride forms when the carboxyl portions of three fatty acids react with the –OH groups of glycerol. This structure contains a lot of energy. Fats and oils are the body’s primary long-term energy storage molecules. © McGraw Hill LLC 23 Figure 3.11 Synthesis and Breakdown of Fat Access the text alternative for slide images. © McGraw Hill LLC 24 8  9/13/2023 Fatty Acids Fatty acids are the primary component of fats and oils. Unsaturated fats have double bonds in the carbon chain wherever the number of hydrogens is less than two per carbon atom. Trans fat is an unsaturated fat (C=C) bond has H’s located on opposite side of bond. Saturated fatty acids have no double bonds between carbon atoms. © McGraw Hill LLC 25 Figure 3.12 Fatty Acids Access the text alternative for slide images. © McGraw Hill LLC 26 Phospholipids: Membrane Components Phospholipids: Form the bulk of the plasma membrane One end of the molecule is water-soluble. Polar phosphate head Other end of the molecule is not water-soluble. Nonpolar fatty acid tails © McGraw Hill LLC 27 9  9/13/2023 Figure 3.13 Phospholipids Form Membranes Hydrophilic Hydrophobic Access the text alternative for slide images. © McGraw Hill LLC 28 Steroids: Four Fused Rings Steroids Lipids made of four fused rings. No fatty acids but are insoluble in water Derived from cholesterol Differ only in functional groups © McGraw Hill LLC 29 Figure 3.14 Steroid Diversity Access the text alternative for slide images. © McGraw Hill LLC 30 10  9/13/2023 3.3 Proteins and Nucleic Acids Proteins Many functions: support, metabolism, transport, defense, regulation, and motion © McGraw Hill LLC 31 3.3 Proteins and Nucleic Acids Proteins are composed of amino acid monomers. Central carbon bonded to hydrogen atom, amino group, carboxyl group, and a side chain, or R group. 20 different amino acids – central carbon atom bonds to a hydrogen atom, two functional groups, and a R group Differ according to R group Amino acid = composed of amino group (-NH2) and carboxyl group (-COOH) © McGraw Hill LLC 32 Figure 3.17 Amino Acids Access the text alternative for slide images. © McGraw Hill LLC 33 11  9/13/2023 Figure 3.16 Protein Foods © McGraw Hill LLC John Thoeming/McGraw Hill 34 Amino Acids and Peptides Peptides: Peptide—two amino acids covalently linked Peptide bond—formed by dehydration reaction between two amino acid monomers Polypeptide—chain of many amino acids joined by peptide bonds Amino acid sequence determines the final three- dimensional shape of protein. © McGraw Hill LLC 35 Figure 3.18 Synthesis and Degradation of Peptide Access the text alternative for slide images. © McGraw Hill LLC 36 12  9/13/2023 Shape of Proteins 1 Function determined by three-dimensional shape Loss of structure and function—denature Usually due to pH or temperature Primary structure—amino acid sequence © McGraw Hill LLC 37 Shape of Proteins 2 Secondary structure—portions of chain form helices or pleated sheets, held together by hydrogen bonds © McGraw Hill LLC 38 Shape of Proteins 3 Tertiary structure—overall three-dimensional shape of interacting secondary structures, held together by R groups © McGraw Hill LLC 39 13  9/13/2023 Shape of Proteins 4 Quaternary structure—more than one polypeptide chain interacting © McGraw Hill LLC 40 Nucleic Acids Deoxyribonucleic acid (DNA) Stores genetic information Ribonucleic acid (RNA) Helps to make proteins Polymers of nucleotide monomers Nucleotide composed of a phosphate, 5-carbon sugar, and nitrogen-containing base Five types of bases—adenine (A), guanine (G), cytosine (C), and thymine (T) [DNA only], Uracil (U) [RNA only] © McGraw Hill LLC 41 Figure 3.20a DNA Structure Nucleotide © McGraw Hill LLC 42 14  9/13/2023 Structure of DNA Deoxyribose as sugar (backbone) Double helix Complementary base pairing Adenine (A) with thymine (T) Cytosine (C) with guanine (G) Genetic information stored in sequence of bases © McGraw Hill LLC 43 Figure 3.20b DNA Structure with Base Pairs Access the text alternative for slide images. © McGraw Hill LLC 44 RNA Bases RNA Ribose as sugar (backbone) Single-stranded Uses uracil (U) instead of thymine (T) © McGraw Hill LLC 45 15  9/13/2023 Figure 3.21 RNA Structure Access the text alternative for slide images. © McGraw Hill LLC 46 Comparing Proteins and Nucleic Acids Sequence of bases in DNA determines sequence of amino acids in a protein. Sequence of amino acids determines a protein's structure and function. Small changes in the DNA may cause large changes in a protein. Sickle-cell disease Individual’s red blood cells are sickle-shaped One amino acid difference Inherited disease © McGraw Hill LLC 47 Figure 3.22 Sickle-Cell Disease Access the text alternative for slide images. © McGraw Hill LLC (photos): Eye of Science/Science Source 48 16  9/13/2023 Because learning changes everything. ® www.mheducation.com © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 17