ch 2Macromolecules: Superstructures of Life

Section 2.2: Macromolecules: Superstructures of Life

Learning Outcomes
  • Name the four main families of biochemicals.
  • Provide examples of cell components made from each of the families of biochemicals.
  • Differentiate among primary, secondary, tertiary, and quaternary levels of protein structure.
  • List the three components of nucleotides.
Overview of Macromolecules
  • Biochemistry: The scientific study of the compounds of life.
  • Four Main Families of Biochemicals:
    • Carbohydrates.
    • Lipids.
    • Proteins.
    • Nucleic acids.
Macromolecules
  • Definition: Large compounds assembled from smaller molecular subunits (monomers).
  • Polymerization Process: Monomers are bound into polymers of varying lengths.
Functions of Macromolecules
  • Structural Components: Provide shape and support to cells.
  • Molecular Messengers: Involved in signaling processes.
  • Energy Sources: Serve as fuel for cellular activities.
  • Enzymes: Act as biochemical catalysts.
  • Nutrient Stores: Reservoirs of nutrients.
  • Genetic Information: Contain and transmit hereditary information.
Carbohydrates
  • General Formula: (CH₂O)n
  • Types of Carbohydrates:
    • Monosaccharides: Simple sugars (3 to 7 carbons) e.g., glucose, fructose.
    • Disaccharides: Composed of two monosaccharides, e.g., sucrose, lactose, maltose.
    • Polysaccharides: Long chains of monosaccharides e.g., starch, cellulose, glycogen.
Glycosidic Bonds
  • Formed between sugar units via dehydration synthesis.
Functions of Polysaccharides
  • Cellulose: Provides rigidity to plant cell walls.
  • Chitin: Component of fungal cell walls.
  • Peptidoglycan: Structural component of bacterial cell walls.
  • Glycocalyx: Involves polysaccharides that aid in cell attachment and recognition.
Lipids
  • Definition: Non-soluble in polar solvents; soluble in nonpolar solvents.
  • Types of Lipids:
    • Triglycerides: Composed of glycerol and three fatty acids; storage form of fats.
    • Phospholipids: Glycerol + two fatty acids + phosphate; form cellular membranes.
    • Steroids: Ring structures, e.g., cholesterol; important for membrane structure.
    • Waxes: Esters of fatty acids and long-chain alcohols; provide waterproofing.
Triglycerides
  • Composed of:
    • Glycerol: A three-carbon alcohol.
    • Fatty Acids: Long hydrocarbon chains.
  • Saturated vs. Unsaturated:
    • Saturated Fatty Acids: Single bonds only.
    • Unsaturated Fatty Acids: Contain one or more double bonds.
Phospholipids
  • Have hydrophilic (water-attracting) heads and hydrophobic (water-repelling) tails; essential for forming bilayers in cell membranes.
Proteins
  • Structure: Comprised of amino acids; functions in enzymatic activity, structure, and transport.
  • Amino Acids: 20 different types, linked by peptide bonds.
Protein Structure Levels
  • Primary Structure: Specific amino acid sequence.
  • Secondary Structure: Folding patterns (alpha helices and beta sheets).
  • Tertiary Structure: Overall 3D shape due to interactions between R groups.
  • Quaternary Structure: Complex of multiple polypeptides.
Enzymes and Antibodies
  • Enzymes: Biological catalysts that facilitate reactions.
  • Antibodies: Proteins that identify and neutralize pathogens.
Nucleic Acids
  • DNA: Contains genetic instructions; composed of nucleotides (nitrogen base, pentose sugar, phosphate).
  • RNA: Involved in protein synthesis; includes mRNA, tRNA, and rRNA.
ATP: The Energy Molecule
  • Structure of ATP: Composed of adenine, ribose, and three phosphate groups.
  • Provides energy when phosphate bonds are broken.