Biological Macromolecules Overview

Aug 29, 2025

Overview

This lecture focuses on the four major biological macromolecules—carbohydrates, lipids, proteins, and nucleic acids—and their roles in chemistry and the body.

Carbohydrates

  • Carbohydrates are organic molecules made of carbon, hydrogen, and oxygen.
  • Main function is energy supply for cells.
  • Monosaccharides are simple sugars (e.g., glucose).
  • Disaccharides consist of two monosaccharides (e.g., sucrose).
  • Polysaccharides are complex carbohydrates (e.g., glycogen, starch).

Lipids

  • Lipids are hydrophobic molecules including fats, oils, and steroids.
  • Main functions are long-term energy storage and insulation.
  • Triglycerides consist of glycerol and three fatty acids.
  • Phospholipids form the main component of cell membranes.
  • Steroids include hormones like cholesterol.

Proteins

  • Proteins are made of amino acids linked by peptide bonds.
  • Function as enzymes, hormones, and structural components.
  • Structure includes primary, secondary, tertiary, and quaternary levels.
  • Denaturation is the loss of protein structure and function.

Nucleic Acids

  • Nucleic acids include DNA and RNA.
  • DNA stores genetic information; RNA helps in protein synthesis.
  • Made of nucleotides containing sugar, phosphate, and nitrogen base.

Key Terms & Definitions

  • Monosaccharide — simple sugar, basic unit of carbohydrates.
  • Disaccharide — molecule of two monosaccharides.
  • Polysaccharide — large carbohydrate made of many monosaccharides.
  • Triglyceride — lipid made from one glycerol and three fatty acids.
  • Phospholipid — lipid with a phosphate group, forms cell membranes.
  • Amino acid — building block of proteins.
  • Peptide bond — bond linking amino acids in proteins.
  • Denaturation — process where proteins lose shape/function.
  • Nucleotide — building block of nucleic acids.

Action Items / Next Steps

  • Review flashcards on each macromolecule.
  • Study diagrams of carbohydrate, lipid, protein, and nucleic acid structures.
  • Complete assigned reading on macromolecules in your textbook.