tailieunhanh - Lecture Biology: Chapter 4 - Niel Campbell, Jane Reece

Chapter 4 - Carbon and the molecular diversity of life. All organisms are composed mostly of chemical structures based on the element carbon. This chapter builds upon information and concepts introduced in Chapters 2 and 3 and extends the descriptions and analysis to more detailed consideration of the carbon atom. | Chapter 4 Carbon and the Molecular Diversity of Life Overview: Carbon: The Backbone of Life Although cells are 70–95% water, the rest consists mostly of carbon-based compounds. Carbon is unparalleled in its ability to form large, complex, and diverse molecules because each carbon atom makes 4 bonds. Proteins, DNA, carbohydrates, and other molecules that distinguish living matter are all composed of carbon compounds. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings What properties of carbon underlie its role as the molecular basis of life? Figure What properties of carbon underlie its role as the molecular basis of life? Organic chemistry is the study of carbon compounds Organic chemistry is the study of compounds that contain carbon. Organic compounds range from simple molecules to colossal ones. Most organic compounds contain hydrogen atoms in addition to carbon atoms. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Stanley Miller Experiment Water vapor H2 NH3 “Atmosphere” Electrode Condenser Cold water Cooled water containing organic molecules Sample for chemical analysis H2O “sea” CH4 Primative Earth Environment Simple Organic Compounds Synthesized Figure Can organic molecules form under conditions believed to simulate those on the early Earth? Carbon atoms can form diverse molecules by bonding to four other atoms Electron configuration is the key to an atom’s characteristics. Electron configuration determines chemical bonding: the kinds and number of bonds an atom will form with other atoms. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Formation of Bonds with Carbon With four valence electrons (outer shell), carbon can form four covalent bonds with a variety of atoms. This tetravalence makes large, complex molecules possible. In molecules with multiple carbons, each carbon bonded to four other atoms has a tetrahedral shape. | Chapter 4 Carbon and the Molecular Diversity of Life Overview: Carbon: The Backbone of Life Although cells are 70–95% water, the rest consists mostly of carbon-based compounds. Carbon is unparalleled in its ability to form large, complex, and diverse molecules because each carbon atom makes 4 bonds. Proteins, DNA, carbohydrates, and other molecules that distinguish living matter are all composed of carbon compounds. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings What properties of carbon underlie its role as the molecular basis of life? Figure What properties of carbon underlie its role as the molecular basis of life? Organic chemistry is the study of carbon compounds Organic chemistry is the study of compounds that contain carbon. Organic compounds range from simple molecules to colossal ones. Most organic compounds contain hydrogen atoms in addition to carbon atoms. Copyright © 2008 Pearson Education, Inc., publishing as Pearson .