KM

Cowan_MicrobiologyCh2

Chapter 02: The Chemistry of Biology

Introduction

  • Focus on the fundamental chemistry that underpins biological systems.

Learning Outcomes

  • Identify the four main families of biochemicals.

  • Provide examples of cell components derived from these families.

  • Differentiate between various levels of protein structure: primary, secondary, tertiary, and quaternary.

  • Outline the components of nucleotides and ATP.

  • Recognize the nitrogen bases found in DNA and RNA.

Macromolecules: Overview

  • Biochemistry: Scientific field studying the compounds essential for life.

  • Four Main Families of Biochemicals:

    • Carbohydrates: Energy sources and structural components.

    • Lipids: Important for membrane structure and energy storage.

    • Proteins: Play diverse roles including structural functions and catalyzing reactions.

    • Nucleic Acids: Store and transmit genetic information.

Carbohydrates: Structure and Examples

  • Monosaccharides: Simple sugars (e.g., glucose, fructose); building blocks for larger carbohydrates.

    • Examples include glucose, fructose.

  • Disaccharides: Formed from two monosaccharides (e.g., maltose, lactose, sucrose).

  • Polysaccharides: Long chains of monosaccharides (e.g., starch, cellulose, glycogen); serve as energy storage and structural elements.

Lipids: Structure and Examples

  • Triglycerides: Composed of glycerol and three fatty acids.

    • Major energy storage form and component of membranes.

  • Phospholipids: Glycerol bound to two fatty acids and a phosphate group.

    • Essential for cell membranes due to hydrophilic and hydrophobic properties.

  • Waxes: Long-chain fatty acids linked to long-chain alcohols; provide waterproofing.

  • Steroids: Four-ring structures (e.g., cholesterol); vital for membrane structure and hormone production.

Proteins: Structure and Function

  • Amino Acids: Building blocks of proteins, 22 different types exist; linked via peptide bonds.

  • Protein Structure Levels:

    • Primary: Sequence of amino acids.

    • Secondary: Local folding patterns (e.g., alpha helices, beta sheets).

    • Tertiary: Overall 3D structure; interactions between distant amino acids and functional groups.

    • Quaternary: Structure formed from multiple polypeptide chains.

  • Functions: Structural roles, enzymes, transport proteins, signaling molecules.

Nucleic Acids: Structure and Examples

  • Components of Nucleotides:

    • Nitrogen base, pentose sugar, phosphate group.

  • Types of Nucleic Acids:

    • DNA: Contains deoxyribose and thymine; stores hereditary information.

    • RNA: Contains ribose and uracil; involved in protein synthesis.

  • Comparison: DNA and RNA differ in sugar types and nitrogen bases (DNA lacks uracil, RNA lacks thymine).

ATP: The Energy Molecule

  • Adenosine Triphosphate (ATP): Composed of adenine, ribose, and three phosphate groups.

  • ATP releases energy when the bond between the second and third phosphates is broken, playing a crucial role in energy transfer within cells.

Cells: Fundamental Unit of Life

  • Characteristics:

    • All living organisms are made of cells; they can be unicellular or multicellular.

    • Eukaryotic cells (with a nucleus) versus prokaryotic cells (without a nucleus).

  • Cells follow the laws of chemistry and physics, producing complex characteristics and reactions essential for life.