Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. MICHAEL D. JOHNSON THE CHEMISTRY OF LIVING THINGS CHAPTER 2 THE CHEMISTRY OF LIVING THINGS PowerPoint ® Lecture Slide Presentation by Robert J. Sullivan, Marist College Human Biology Concepts and Current Issues Second Edition
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Atoms, the smallest functional unit, consist of: Protons: positive charge, have mass Neutrons: no charge, have mass Electrons: negative charge, have no discernable mass All Matter Consists of Elements Made of Atoms
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Same element, same atomic number = same number of protons and electrons Different number of neutrons = different weight Isotopes
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Are unstable (varies with isotope) Emit energy (radiation) Emit particles Radioisotopes
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Joining atoms requires energy Energy is the capacity to do work 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 Atoms Combine to Form Molecules
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Three Types of Chemical Bonds Table 2.1
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Elements of Living Organisms Table 2.2
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Water molecules are polar Water is liquid at body temperature Water can absorb and hold heat energy Life Depends on Water
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Water is the biological solvent Water helps regulate body temperature Two Important Biological Functions of Water
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Water Keeps Ions in Solution Figure 2.9
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. 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 The Importance of Hydrogen Ions
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. The pH Scale Figure 2.11
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. 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 The Organic Molecules of Living Organisms
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Carbon Can Bond in Many Ways Figure 2.13
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Making and Breaking Biological Macromolecules: Dehydration Synthesis and Hydrolysis Figure 2.14
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. 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 Dehydration Synthesis is the Reverse of Hydrolysis
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Carbohydrates are Composed of Monosaccharides Figure 2.15
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Oligosaccharides: short chains of monosaccharides Disaccharides: sucrose, fructose, lactose Polysaccharides: thousands of monosaccarides joined in chains and branches Starch: made in plants; stores energy Glycogen: made in animals; stores energy Cellulose: undigestible polysaccharide made in plants for structural support Carbohydrates are Used for Energy and Structural Support
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Triglycerides: energy storage molecules Fatty acids: saturated and unsaturated Phospholipids: cell membranes Steroids: carbon-based ring structures Cholesterol: used in making estrogen and testosterone Lipids: Insoluble in Water
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Structure Primary: amino acid sequence Secondary: describes chain’s orientation in space; e.g., alpha helix, beta sheet Tertiary: describes three-dimensional shape created by disulfide and hydrogen bonds Creates polar and nonpolar areas in molecule Quaternary: describes proteins in which two or more tertiary protein chains are associated Proteins: Complex Structures Constructed of Amino Acids
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Enzymes: are proteins function as catalysts facilitate chemical reactions The functional shape of an enzyme is dependent on: temperature of reaction medium pH ion concentration presence of inhibitors Enzyme Function
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Functions Store genetic information Provide information used in making proteins 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 Structure and Function of Nucleic Acids
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. 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 Structure of DNA and RNA
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings. Structure and Function of Adenosine Triphosphate (ATP) Figure 2.26