Chapter 2: Chemical Principles

Chemical Principles begins by explaining the structure of atoms, including protons, neutrons, and electrons, and how their arrangement determines atomic number, isotopes, and reactivity. The chapter then discusses how atoms form molecules through ionic and covalent bonds, and how hydrogen bonds contribute to the unique properties of water. Key chemical reactions in microbial life—synthesis, decomposition, and exchange reactions—are introduced, along with the role of activation energy and enzymes in catalyzing biochemical reactions. The chapter emphasizes water's critical role in life due to its polarity, solvent capabilities, temperature-stabilizing effects, and participation in hydrolysis and dehydration synthesis. Acids, bases, salts, and the pH scale are covered with a focus on their biological significance in maintaining microbial homeostasis. The chapter then shifts to organic compounds, defining and explaining carbohydrates, lipids, proteins, and nucleic acids in detail. Carbohydrates are described as energy sources and structural molecules, while lipids, including phospholipids, are shown to play a major role in cell membranes. Proteins are explored through their amino acid building blocks, levels of structure (primary to quaternary), and diverse functional roles like enzymes, transport, and motility. Nucleic acids—DNA and RNA—are introduced as carriers of genetic information, and ATP is explained as the energy currency of the cell. By grounding microbiology in core chemistry principles, this chapter equips students to understand how microscopic life operates on a molecular level, setting the stage for all further biological processes discussed in the book.