Chapter 4: Carbon and the Molecular Diversity of Life PDF

Chapter 4 Carbon and the Molecular Diversity of Life Lecture Presentations by Nicole Tunbridge and © 2021 Pears...

Chapter 4 Carbon and the Molecular Diversity of Life Lecture Presentations by Nicole Tunbridge and © 2021 Pearson Education, Inc. Kathleen Fitzpatrick 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 © 2021 2017 Pearson Education, Inc. Figure 4.1 © 2021 Pearson Education, Inc. Figure 4.1a © 2021 Pearson Education, Inc. CONCEPT 4.1: Organic chemistry is key to the origin of life Organic chemistry is the study of compounds that contain carbon, regardless of origin Organic compounds range from simple molecules to colossal ones © 2021 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 © 2021 Pearson Education, Inc. Figure 4.2 © 2021 Pearson Education, Inc. Organic Molecules and the Origin of Life on Earth (Cont’d) The overall percentages of the major elements of life—C, H, O, N, S, and P—are quite uniform from one organism to another Because carbon can form four bonds, these building blocks can be used to make an inexhaustible variety of organic molecules The great diversity of organisms on the planet is due to the versatility of carbon © 2021 Pearson Education, Inc. CONCEPT 4.2: Carbon atoms can form diverse molecules by bonding to four other atoms Electron configuration is the key to an atom’s chemical characteristics Electron configuration determines the kinds and number of bonds an atom will form with other atoms © 2021 Pearson Education, Inc. The Formation of Bonds with Carbon With four valence electrons, carbon can form four covalent bonds with a variety of atoms This enables carbon to form large, complex molecules In molecules with multiple carbons, each carbon bonded to four other atoms has a tetrahedral shape However, when two carbon atoms are joined by a double bond, the atoms joined to the carbons are in the same plane as the carbons The number of unpaired electrons in the valence shell of an atom is generally equal to its valence, the number of covalent bonds it can form © 2021 Pearson Education, Inc. Figure 4.3 © 2021 Pearson Education, Inc. Figure 4.4 © 2021 Pearson Education, Inc. The Formation of Bonds with Carbon (Cont’d) The electron configuration of carbon gives it covalent compatibility with many different elements The most frequent bonding partners of carbon are hydrogen, oxygen, and nitrogen © 2021 Pearson Education, Inc. Molecular Diversity Arising from Variation in Carbon Skeletons Carbon atoms can partner with atoms other than hydrogen, such as the following: – Carbon dioxide: CO2 O O © 2021 Pearson Education, Inc.  – Urea: CO(NH2)2 © 2021 Pearson Education, Inc.  – Carbon atoms can also be linked into chains as shown for C3H8 © 2021 Pearson Education, Inc. Molecular Diversity Arising from Variation in Carbon Skeletons (Cont’d) Carbon chains form the skeletons of most organic molecules Carbon chains vary in length and shape © 2021 Pearson Education, Inc. Figure 4.5 © 2021 Pearson Education, Inc. Animation: Diversity of Carbon-Based Molecules © 2021 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 © 2021 Pearson Education, Inc. Figure 4.6 © 2021 Pearson Education, Inc. Isomers Isomers are compounds with the same molecular formula but different structures and properties – Structural isomers have different covalent arrangements of their atoms – Cis-trans isomers (also called geometric isomers) have the same covalent bonds but differ in their spatial arrangements – Enantiomers are isomers that are mirror images of each other © 2021 Pearson Education, Inc. Figure 4.7 © 2021 Pearson Education, Inc. Animation: Isomers © 2021 Pearson Education, Inc. Isomers (Cont’d) Enantiomers are important in the pharmaceutical industry Two enantiomers of a drug may have different effects Often only one enantiomer is biologically active Differing effects of enantiomers demonstrate that organisms are sensitive to even subtle variations in molecules © 2021 Pearson Education, Inc. Figure 4.8 © 2021 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 the chemical groups attached to it These groups help give each molecule its unique properties © 2021 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 © 2021 Pearson Education, Inc. UNF04-06 © 2021 Pearson Education, Inc. Functional Groups 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 © 2021 Pearson Education, Inc. Functional Groups (Cont’d) The seven functional groups that are most important in the chemistry of life are the following: – Hydroxyl group – Carbonyl group – Carboxyl group – Amino group – Sulfhydryl group – Phosphate group – Methyl group © 2021 Pearson Education, Inc. Figure 4.9 © 2021 Pearson Education, Inc. Animation: Functional Groups © 2021 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 This reaction releases energy that can be used by the cell © 2021 Pearson Education, Inc. UNF04-07 © 2021 Pearson Education, Inc. UNF04-08 © 2021 Pearson Education, Inc. The Chemical Elements of Life: A Review The versatility of carbon makes possible the great diversity of organic molecules Variation at the molecular level lies at the foundation of all biological diversity on our planet © 2021 Pearson Education, Inc.  THE END © 2021 Pearson Education, Inc.