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2 The Chemistry of Living Things PowerPoint® Lecture Slide Presentation Robert J. Sullivan, Marist College Michael D. Johnson Human Biology Concepts and Current Issues THIRD EDITION Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. All Matter Consists of Elements Made of Atoms Atoms, the smallest functional unit, consist of: Protons: positive charge, have mass Neutrons: no charge, have mass Electrons: negative charge, have no discernable mass Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Radioisotopes Atoms Combine to Form Molecules Are unstable (varies with isotope) Joining atoms requires energy Emit energy (radiation) Energy is the capacity to do work Emit particles Stored energy = potential energy Energy in motion, doing work = kinetic energy Electrons have potential energy Shells = the energy levels of electrons Orbitals describe the probable location of an electron Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. 1 Three Types of Chemical Bonds PLAY Press to play Covalent Bonds animation PLAY Press to play Ionic Bonds animation Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Table 2.1 Elements of Living Organisms Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Life Depends on Water Water molecules are polar Water is liquid at body temperature Water can absorb and hold heat energy Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Table 2.2 Two Important Biological Functions of Water Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Water Keeps Ions in Solution Water is the biological solvent Water helps regulate body temperature Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Figure 2.9 2 The Importance of Hydrogen Ions The pH ScaleThe Organic Molecules of Living Organisms Acids are proton (hydrogen ion) donors, bases accept hydrogen ions pH Scale = hydrogen ion concentration Buffers: minimize pH change Carbonic acid and bicarbonate act as one of body’s most important buffer pairs Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Figure 2.11 Carbon Can Bond in Many Ways Carbon, the building block of living things: Comprises 18% of body by weight Forms four covalent bonds Can form single or double bonds Can build micro- or macromolecules Figure 2.13 Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Making and Breaking Biological Macromolecules: Dehydration Synthesis and Hydrolysis Dehydration Synthesis is the Reverse of Hydrolysis Dehydration synthesis Removes equivalent of a water molecule to link molecular units Requires energy Hydrolysis Adds the equivalent of a water molecule to break apart macromolecules Releases energy Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Figure 2.14 Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. 3 4 Macromolecules of Life Carbohydrates Carbohydrates Monosaccharides Single sugar units Proteins Disaccharides Lipids Double sugar units Nucleic Acids Oligosaccharides Multiple sugar units Polysaccharides Starch Glycogen cellulose Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Carbohydrates are Composed of Monosaccharides Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Figure 2.15 Carbohydrates are Used for Energy and Structural Support Oligosaccharides: short chains of monosaccharides Disaccharides: sucrose, fructose, lactose Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Carbohydrates are Used for Energy and Structural Support Polysaccharides: thousands of monosaccarides joined in chains and branches Starch: made in plants; stores energy Glycogen: made in animals; stores energy Cellulose: indigestible polysaccharide made in plants for structural support PLAY Press to play Disaccharides animation Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. PLAY Press to play Polysaccharides animation Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. 4 Proteins 4 structural levels of Assembly Primary Secondary Tertiary Quartenary Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Proteins: Complex Structures Constructed of Amino Acids Proteins: Complex Structures Constructed of Amino Acids Structure PLAY Press to play Introduction to Protein Structure animation Tertiary: describes three-dimensional shape created by disulfide and hydrogen bonds Creates polar and nonpolar areas in molecule Primary: amino acid sequence PLAY Press to play Chemistry of Life© Proteins: Primary Structure animation Secondary: describes chain’s orientation in space, e.g., alpha helix, beta sheet PLAY Press to play Chemistry of Life© Proteins: Secondary Structure animation Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. PLAY Press to play Chemistry of Life© Proteins: Tertiary Structure animation Quaternary: describes proteins in which two or more tertiary protein chains are associated PLAY Press to play Chemistry of Life© Proteins: Quaternary Structure animation Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. 5 Enzyme Function Enzyme Function Enzymes: The functional shape of an enzyme is dependent on: are proteins temperature of reaction medium function as catalysts pH facilitate chemical reactions ion concentration presence of inhibitors PLAY Press to play Chemistry of Life© Proteins: Enzyme animation Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Lipids: Insoluble in Water Structure and Function of Nucleic Acids Triglycerides: energy storage molecules Fatty acids: saturated and unsaturated Functions Store genetic information Provide information used in making proteins Phospholipids: cell membranes Steroids: carbon-based ring structures Cholesterol: used in making estrogen and testosterone PLAY Press to play Fats animation Structure Nucleotides consist of a phosphate group, a sugar, and a nitrogenous base DNA structure is a double helix: two associated strands of nucleic acids RNA is a single-stranded molecule Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Structure of DNA and RNA Structure and Function of Adenosine Triphosphate (ATP) DNA: double-stranded Sugar: deoxyribose Nitrogenous bases: adenine, thymine, cytosine, guanine Pairing: adenine-thymine and cytosine-guanine RNA: single-stranded Sugar: ribose Nitrogenous bases: adenine, uracil, cytosine, guanine Pairing: adenine-uracil, cytosine-guanine Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. Figure 2.26 6 Lecture Review Outline – Chapter 2 Chemistry Definitions Importance of Water pH Scale Bonds Macromolecules of Life Carbohydrates Lipids Proteins Nucleic acids Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings. 7
