Key Vocabulary for Organic Molecules (General Biology Ch. 5)

Organic Molecules: Key Vocabulary and Concepts

Introduction

This section provides definitions and explanations of essential terms related to organic molecules, as covered in General Biology Chapter 5. Understanding these terms is fundamental for grasping the structure, function, and diversity of biological macromolecules.

Major Terms and Definitions

• Carbon: The central element in organic chemistry, capable of forming four covalent bonds, allowing for diverse molecular structures.

• Monomers: Small, repeating units that serve as the building blocks of polymers.

• Polymers or Macromolecules: Large molecules composed of many monomers linked together by covalent bonds.

• Condensation/Dehydration Reactions: Chemical reactions that join monomers by removing a molecule of water.

• Hydrolysis Reactions: Chemical reactions that break polymers into monomers by adding water.

• Carbohydrates: Organic molecules consisting of carbon, hydrogen, and oxygen, often with the formula $(CH_2O)_n$; serve as energy sources and structural materials.

• Monosaccharides: Simple sugars (e.g., glucose, fructose) that are the monomers of carbohydrates.

• Disaccharides: Carbohydrates formed by joining two monosaccharides (e.g., sucrose, lactose).

• Polysaccharides: Long chains of monosaccharides; examples include starch, glycogen, and cellulose.

• Lipids: Hydrophobic molecules including fats, oils, phospholipids, and steroids; important for energy storage and membrane structure.

• Saturated Fatty Acids: Fatty acids with no double bonds between carbon atoms; typically solid at room temperature.

• Unsaturated Fatty Acids: Fatty acids with one or more double bonds; usually liquid at room temperature.

• Glycerol: A three-carbon alcohol that forms the backbone of triglycerides and phospholipids.

• Triglycerides (Fats): Lipids formed from one glycerol and three fatty acids; major energy storage molecules.

• Phospholipids: Lipids with a phosphate group; major components of cell membranes.

• Waxes: Lipids that serve as waterproof coatings in plants and animals.

• Steroids: Lipids with a structure of four fused rings; include hormones like cholesterol and testosterone.

• Proteins: Polymers of amino acids; perform a wide range of functions including catalysis, structure, and transport.

• Amino Acids: The monomers of proteins; each contains an amino group, carboxyl group, hydrogen atom, and variable R group.

• Peptide Bonds: Covalent bonds that link amino acids in proteins.

• Primary Structure: The unique sequence of amino acids in a protein.

• Secondary Structure: Local folding of a protein into alpha helices or beta sheets, stabilized by hydrogen bonds.

• Tertiary Structure: The overall three-dimensional shape of a protein, determined by interactions among R groups.

• Quaternary Structure: The structure formed by the association of multiple protein subunits.

• Denaturation: The loss of a protein's native structure due to environmental changes, causing loss of function.

• Nucleic Acids: Polymers of nucleotides; store and transmit genetic information (DNA and RNA).

• Nucleotides: The monomers of nucleic acids, each consisting of a sugar, phosphate group, and nitrogenous base.

• Nitrogenous Bases: The components of nucleotides that include adenine, thymine, cytosine, guanine, and uracil.

• ATP (Adenosine Triphosphate): The primary energy carrier in cells.

Examples and Applications

• Example of a Condensation Reaction: Formation of a peptide bond between two amino acids, releasing water.

• Application: Phospholipids form the bilayer structure of cell membranes, critical for cell function.

Additional info:

• Understanding the structure and function of macromolecules is essential for topics such as metabolism, genetics, and cell biology.

• Many diseases are linked to the malfunction or misfolding of proteins (e.g., sickle cell anemia, Alzheimer's disease).