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).