Biological Macromolecules Review

Biological Macromolecules

  • Definition: Very large molecules built from smaller organic molecules (monomers) joined by covalent bonds.
  • Four Major Types:
    • Carbohydrates
    • Lipids
    • Proteins
    • Nucleic acids

Organic Molecules

  • Characteristics:
    • Composed of hydrocarbons (carbon and hydrogen).
    • Associated with living or once-living organisms.
    • Not to be confused with CO2 (carbon dioxide).

Learning Goals

  • Describe the four major types of biological molecules.
  • Summarize the general characteristics and functions of each biomolecule.

Biological Macromolecules Characteristics

  • All biological macromolecules are organic and contain hydrocarbons.
  • May also include elements like oxygen, nitrogen, phosphorus, and sulfur.

Key Vocabulary

  • Monomer: A single unit (in Greek, "mono" means one).
  • Polymer: A chain of monomers (in Greek, "poly" means many).

Carbohydrates

  • General Formula: Cn(H2O)n
    • Ratio of carbon to hydrogen to oxygen is 1:2:1.
  • Subtypes:
    1. Monosaccharides (single saccharides).
    • Examples:
      • Glucose (found in pasta, whole grains, vegetables).
      • Galactose (found in milk).
      • Fructose (found in fruits).
      • Note: Glucose, Galactose, and Fructose are isomers.
    1. Disaccharides (two saccharides).
    • Examples:
      • Maltose (Glucose + Glucose).
      • Sucrose (Glucose + Fructose).
      • Lactose (Glucose + Galactose).
    1. Polysaccharides (many saccharides).
    • Examples:
      • Starch/Amylose - storage in plants.
      • Glycogen - storage in animals (liver and muscles).
      • Cellulose - structural in plant cell walls (indigestible by humans).
      • Chitin - structural in arthropods (exoskeleton).
    1. Oligosaccharides (2-10 monosaccharides linked by glycosidic bonds).

Lipids

  • Definition: Molecules categorized by their hydrophobic properties.
  • Functions:
    • Stored energy, insulation, cushioning organs.
    • Examples include fats, oils, waxes, and steroids.
  • Types:
    1. Triglycerides
    • Composed of glycerol and three fatty acids.
    • Solid (fat) vs. liquid (oil).
    1. Phospholipids
    • Composed of glycerol, two fatty acids, and a phosphate group, crucial in cell membranes.
    1. Waxes
    • Solid at room temp, used for waterproofing surfaces.
    1. Steroids
    • Four fused carbon rings structure (e.g., cholesterol, sex hormones).

Proteins

  • Composition: Composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
  • Building Blocks: Amino acids (20 essential and non-essential amino acids).
  • Bonding:
    • Amino acids linked by peptide bonds to form polypeptides.
  • Functions:
    • Enzymes, structural components, transport, signaling (hormones), and immune defense (antibodies).
  • Examples:
    • Enzymes (lipase, pepsin, amylase).
    • Hemoglobin (oxygen transport).
    • Myoglobin (oxygen storage in muscles).
    • Collagen (connective tissues).
    • Keratin (hair, skin, nails).

Nucleic Acids

  • Definition: Large complex molecules important for genetic information.
  • Components: Nucleotides (three parts: phosphate group, sugar, nitrogenous base).
  • Types:
    1. DNA: Carries genetic code (deoxyribonucleic acid).
    2. RNA: Transfers information from DNA for protein synthesis (ribonucleic acid).
  • Differences Between DNA and RNA:
    • DNA: Double-stranded, includes thymine, deoxyribose sugar.
    • RNA: Single-stranded, includes uracil, ribose sugar.
  • Protein Synthesis:
    • Involves transcription (copying DNA to mRNA) and translation (mRNA to protein synthesis in ribosomes).