Carbon and Organic Compounds

Introduction to Organic Compounds

Organic compounds are molecules that contain a backbone of carbon atoms. The versatility of carbon allows it to form a wide variety of structures, which are essential for life.

• Organic compounds are defined by the presence of both carbon and hydrogen atoms.

• Examples include ethanol () and glucose ().

• Carbon atoms can be arranged in linear chains or rings, forming the backbone of organic molecules.

Example: Glucose is a ring-shaped organic molecule essential for cellular energy.

Carbon: The Building Block of Life

Properties of Carbon

Carbon is fundamental to all known life forms due to its unique chemical properties.

• Carbon can form up to four covalent bonds with other atoms, allowing for complex and diverse molecular structures.

• Organic molecules are considered organic only if they contain both carbon and hydrogen.

• All living organisms on Earth are carbon-based.

• Scientists search for carbon-based molecules as evidence of life on other planets.

Additional info: Silicon is sometimes considered as an alternative backbone for life, but carbon's versatility makes it superior for biological molecules.

Structure and Bonding of Carbon

Valence Electrons and Bond Formation

Carbon's ability to form multiple bonds is due to its four valence electrons.

• Carbon has four valence electrons in its outer shell.

• It can achieve a full valence shell by accepting, donating, or sharing electrons with other atoms.

• Carbon commonly forms single, double, or triple covalent bonds with hydrogen, oxygen, and nitrogen.

Equation:

Organic Building Blocks

Major Classes of Organic Molecules

Biological macromolecules are built from smaller organic building blocks.

• Carbohydrates and lipids

• Amino acids and proteins

• Nucleic acids (RNA & DNA)

• Some proteins require metal atoms (e.g., iron, copper, magnesium)

Example: Proteins are polymers of amino acids, which contain both amino and carboxyl functional groups.

Diversity of Carbon Skeletons

Structural Variations

Carbon skeletons can vary in length, branching, and ring formation, contributing to molecular diversity.

• Linear chains, branched chains, and rings are common arrangements.

• Examples: Butane (linear), Isobutane (branched), Cyclohexane (ring).

Hydrocarbons

Definition and Properties

Hydrocarbons are the simplest organic compounds, consisting only of carbon and hydrogen.

• Hydrocarbons are hydrophobic and release energy when broken down.

• Examples: Propane (), Benzene (), Octane (component of gasoline).

Isomers

Types of Isomers

Isomers are molecules with the same molecular formula but different structures.

• Structural isomers: Differ in covalent arrangement of atoms.

• Cis-trans isomers: Differ in spatial arrangement around a double bond.

• Enantiomers: Mirror-image isomers (important in pharmaceuticals).

Example: Butane and isobutane are structural isomers.

Functional Groups

Overview of Functional Groups

Functional groups are specific groups of atoms within molecules that confer distinct chemical properties.

• Functional groups determine the reactivity and interactions of organic molecules.

• They are essential for the structure and function of biological macromolecules.

Major Functional Groups in Biology

ATP: Cellular Energy

Role of ATP in Cells

Adenosine triphosphate (ATP) is the primary energy carrier in cells.

• ATP contains three phosphate groups, which store potential energy.

• Energy is released when ATP is hydrolyzed to ADP (adenosine diphosphate) and inorganic phosphate.

Equation: Example: ATP powers muscle contraction, active transport, and biosynthesis.

Summary Table: Functional Groups and Their Properties

Key Terms and Definitions

• Organic molecule: A molecule containing both carbon and hydrogen.

• Isomer: Molecules with the same molecular formula but different structures.

• Functional group: A specific group of atoms within a molecule responsible for characteristic reactions.

• ATP (Adenosine triphosphate): The main energy currency of the cell.