CAMPBELL BIOLOGY Reece Urry Cain Wasserman Minorsky Jackson © 2014 Pearson Education, Inc. TENTH EDITION CAMPBELL BIOLOGY Reece Urry Cain Wasserman Minorsky Jackson TENTH EDITION 4 Carbon and the Molecular Diversity of Life Lecture Presentation by Nicole Tunbridge and Kathleen Fitzpatrick

© 2014 Pearson Education, Inc. Carbon: The Backbone of Life  Living organisms consist mostly of carbon-based compounds  Carbon is unparalleled in its ability to form large, complex, and varied molecules  Proteins, DNA, carbohydrates, and other molecules that distinguish living matter are all composed of carbon compounds

© 2014 Pearson Education, Inc. Figure 4.1a Carbon can bond to four other atoms or groups of atoms, making a large variety of molecules possible. With four valence electrons, carbon can form four covalent bonds with a variety of atoms This ability makes large, complex molecules possible

© 2014 Pearson Education, Inc. Organic Molecules and the Origin of Life on Earth  Stanley Miller’s classic experiment demonstrated the abiotic synthesis of organic compounds  Experiments support the idea that abiotic synthesis of organic compounds, perhaps near volcanoes, could have been a stage in the origin of life

© 2014 Pearson Education, Inc. Figure 4.2 Water vapor Cooled “rain” containing organic molecules Sample for chemical analysis Cold water Condenser Electrode “Atmosphere” CH 4 NH 3 H2H2 H 2 O “sea ”

© 2014 Pearson Education, Inc. Molecular Diversity Arising from Variation in Carbon Skeletons  Carbon chains form the skeletons of most organic molecules  Carbon chains vary in length and shape

© 2014 Pearson Education, Inc. Figure 4.5 (a) Length (b) Branching(d) Presence of rings (c) Double bond position EthanePropane1-Butene2-Butene Butane2-Methylpropane (isobutane) Cyclohexane Benzene

© 2014 Pearson Education, Inc. Animation: Carbon Skeletons

© 2014 Pearson Education, Inc. Hydrocarbons  Hydrocarbons are organic molecules consisting of only carbon and hydrogen  Many organic molecules, such as fats, have hydrocarbon components  Hydrocarbons can undergo reactions that release a large amount of energy

© 2014 Pearson Education, Inc. Figure 4.6 Nucleus Fat droplets (b) A fat molecule(a) Part of a human adipose cell 10 μ m

© 2014 Pearson Education, Inc. Concept 4.3: A few chemical groups are key to molecular function  Distinctive properties of organic molecules depend on the carbon skeleton and on the chemical groups attached to it  A number of characteristic groups can replace the hydrogens attached to skeletons of organic molecules

© 2014 Pearson Education, Inc. The Chemical Groups Most Important in the Processes of Life  Estradiol and testosterone are both steroids with a common carbon skeleton, in the form of four fused rings  These sex hormones differ only in the chemical groups attached to the rings of the carbon skeleton

© 2014 Pearson Education, Inc. Figure 4.UN03 EstradiolTestosterone

© 2014 Pearson Education, Inc.  Functional groups are the components of organic molecules that are most commonly involved in chemical reactions  The number and arrangement of functional groups give each molecule its unique properties

© 2014 Pearson Education, Inc. Figure 4.9 Chemical GroupCompound Name Examples Ethanol Propanal Acetone Acetic acid Glycine Cysteine Glycerol phosphate Organic phosphate Thiol Amine Carboxylic acid, or organic acid Ketone Aldehyde AlcoholHydroxyl group (—OH) Carboxyl group (—COOH) Amino group (—NH 2 ) Sulfhydryl group (—SH) Phosphate group (—OPO 3 2− ) Methyl group (—CH 3 ) Methylated compound 5-Methyl cytosine Carbonyl group ( C ＝ O) — —

© 2014 Pearson Education, Inc. ATP: An Important Source of Energy for Cellular Processes  An important organic phosphate is adenosine triphosphate (ATP)  ATP consists of an organic molecule called adenosine attached to a string of three phosphate groups  ATP stores the potential to react with water, a reaction that releases energy to be used by the cell

© 2014 Pearson Education, Inc. Figure 4.UN04 Adenosine

© 2014 Pearson Education, Inc. Figure 4.UN05 Reacts with H 2 O Inorganic phosphate ADP Energy Adenosine ATP PPPPPP i