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Biomolecules Overview

Aug 23, 2025

Overview

This lecture introduces the four major biomolecules essential for life—carbohydrates, lipids, proteins, and nucleic acids—covering their building blocks, main functions, and key elements.

Introduction to Biomolecules

  • Biomolecules are large molecules essential for life, obtained from food.
  • There are four major biomolecules: carbohydrates, lipids, proteins, and nucleic acids.

Monomers: The Building Blocks

  • A monomer is a small unit or building block that makes up larger molecules.

Carbohydrates

  • Carbohydrates provide a fast source of energy (e.g., pasta, bread).
  • The monomer for carbohydrates is a monosaccharide.
  • Example: Marathon runners eat high-carb meals for quick energy (carb loading).

Lipids

  • Lipids, also called fats, are made from fatty acids and glycerol.
  • Lipids provide long-term energy storage and insulation (e.g., blubber in seals).
  • Lipids are found in foods like butter, oil, and cholesterol.
  • Cell membranes are made of lipids.
  • Excessive lipid intake can harm health; moderation is important.

Proteins

  • Proteins are important for muscle building and are found in meats and beans.
  • The monomer of proteins is the amino acid.
  • Proteins function in the immune system and as enzymes.
  • DNA codes for proteins that determine body structure and function.

Nucleic Acids

  • Nucleic acids include DNA and RNA, which store genetic information.
  • Their monomer is the nucleotide.
  • Nucleic acids are found in all living things, including the foods we eat.

Major Elements in Biomolecules

  • Use the mnemonic CHO, CHO, CHON, CHONP for major elements:
    • Carbohydrates: Carbon, Hydrogen, Oxygen (CHO)
    • Lipids: Carbon, Hydrogen, Oxygen (CHO)
    • Proteins: Carbon, Hydrogen, Oxygen, Nitrogen (CHON)
    • Nucleic Acids: Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus (CHONP)
  • Differences in element arrangements (rings or chains) affect biomolecule properties and function.

Key Terms & Definitions

  • Biomolecule — a large molecule necessary for life, often made of repeating units.
  • Monomer — a single building block that forms larger molecules.
  • Monosaccharide — monomer of carbohydrates.
  • Fatty Acid & Glycerol — building blocks of lipids.
  • Amino Acid — monomer of proteins.
  • Nucleotide — monomer of nucleic acids.
  • Enzyme — a protein that speeds up chemical reactions in the body.

Action Items / Next Steps

  • Research and review diagrams of biomolecule structures to understand element arrangements.
  • Memorize the CHO, CHO, CHON, CHONP mnemonic for major biomolecule elements.