1.5

Chapter 4 Carbon and the Molecular Diversity of Life

Introduction

• Presenters: Nicole Tunbridge and Kathleen Fitzpatrick

• Year: © 2017 Pearson Education, Inc.

Carbon: The Backbone of Life

• Living Organisms Composition:

  • Mostly consist of carbon-based compounds

• Unique Properties of Carbon:

  • Unparalleled ability to form large, complex, and varied molecules

• Key Molecules:

  • Proteins, DNA, carbohydrates, and other molecules that distinguish living matter are composed of carbon compounds

Concept 4.1: Organic Chemistry

• Definition:

  • Organic chemistry is the study of carbon compounds, regardless of origin.

• Organic Compounds Diversity:

  • Range from simple molecules to colossal compounds.

Organic Molecules and the Origin of Life

• Stanley Miller’s Experiment:

  • Demonstrated the abiotic synthesis of organic compounds.

  • Suggested that abiotic synthesis of organic compounds, potentially near volcanoes, could have been a stage in the origin of life.

Abundance of Elements in Life

• Uniformity Across Organisms:

  • Overall percentages of major elements (C, H, O, N, S, P) are quite uniform across different organisms.

• Carbon Versatility:

  • Carbon's ability to form four bonds allows for an inexhaustible variety of organic molecules.

  • The diversity of organisms on the planet is attributed to carbon's versatility.

Concept 4.2: Carbon Bonding

• Diverse Molecules Formation:

  • Carbon atoms can form diverse molecules by bonding to four other atoms.

• Electron Configuration's Role:

  • Electron configuration is crucial to an atom's characteristics, determining the kinds and number of bonds an atom can form.

• Carbon's Valence Electrons:

  • Carbon has four valence electrons enabling it to form four covalent bonds with various atoms, creating large, complex molecules.

Carbon Molecules Shapes

• Carbon's Tetrahedral Shape:

  • Molecules with multiple carbons and four other atoms have a tetrahedral molecular shape.

• Double Bond Effects:

  • When two carbon atoms are joined by a double bond, the surrounding atoms are in the same plane as the carbon atoms.

Properties of Covalent Bonds with Carbon

• Unpaired Electrons:

  • The number of unpaired electrons in an atom's valence shell generally equals its valence, indicating the number of covalent bonds it can form.

• Compatibility and Valences:

  • The electron configuration of carbon allows for compatibility in forming covalent bonds with many different elements, creating the architecture for living molecules.

Carbon Compounds Variability

• Structural Diversity:

  • Carbon chains form the skeletons of most organic molecules, and these chains can vary in length and shape.

Hydrocarbons

• Definition:

  • Hydrocarbons are organic molecules consisting solely of carbon and hydrogen.

• Function in Organic Molecules:

  • Many organic molecules, such as fats, possess hydrocarbon components.

• Energy Release:

  • Hydrocarbons undergo reactions that release large amounts of energy.

Isomers

• Definition:

  • Isomers are compounds with the same molecular formula but differing in structures and properties.

• Types of Isomers:

  • Structural Isomers: Different covalent arrangements of atoms.

  • Cis-Trans Isomers: Same covalent bonds but differences in spatial arrangements.

  • Enantiomers: Isomers that are mirror images of each other.

Importance of Isomers

• Pharmaceutical Applications:

  • Enantiomers play a significant role in the pharmaceutical industry, where different isomers may produce different biological effects.

  • Often, only one enantiomer is biologically active.

Functional Groups in Organic Molecules

• Definition:

  • Functional groups are components of organic molecules most commonly involved in chemical reactions and determine the unique properties of molecules.

• Key Functional Groups:

  • Hydroxyl Group (-OH)

  • Carbonyl Group (>C=O)

  • Carboxyl Group (-COOH)

  • Amino Group (-NH2)

  • Sulfhydryl Group (-SH)

  • Phosphate Group (-OPO₃²⁻)

  • Methyl Group (-CH₃)

Case Studies of Functional Groups

• Estradiol vs Testosterone:

  • Both are steroids with the same carbon skeleton but differ in their attached chemical groups.

• Chemical Group Characteristics:

  • Example: Hydroxyl group produces alcohol; carboxyl group acts as an acid; amino group acts as a base.

ATP and Energy Transfer

• Adenosine Triphosphate (ATP):

  • An important organic phosphate critical for cellular processes.

  • Consists of adenosine attached to a string of three phosphate groups.

• Energy Release Mechanism:

  • ATP reacts with water, releasing energy that can be harnessed by the cell.

Review of Chemical Elements in Life

• Carbon's Role:

  • The versatility of carbon allows the creation of a wide variety of organic molecules leading to biological diversity.

• Foundation of Biological Diversity:

  • Variations at the molecular level underpin all biological diversity.

Additional Insights from Miller's Experiment

• Experimental Data:

  • Documented various starting reactions and combinations leading to the synthesis of organic compounds.

Illustrative Figures and Diagrams

• Include diagrams detailing molecular structures, functional groups, and the formation of bonds with carbon throughout relevant sections.

Final Notes

• Ensure comprehensive understanding of organic chemistry and the significance of carbon in the molecular diversity essential for life.