Introduction to Metabolism

Lesson 16 : Metabolic Pathways

Introduction to Metabolism

Metabolism - sum total of all chemical reactions in living cells

Catabolic reactions - degrade macromolecules and other molecules to release energy

Anabolic reactions - used to synthesize macromolecules for cell growth, repair, and reproduction

Metabolism can be divided into 4 groups: carbohydrates, lipids, amino acids, nucleotides.

  1. within each group are a set of pathways
  2. arbitrarily set start and end points for ease of learning and reference
  3. pathways can take different forms:

    • Linear - product of one reaction is substrate for another
    • e.g. glycolysis

    • Cyclic - regeneration of intermediates
    • e.g. Krebs cycle

    • Spiral - same set of enzymes are used repeatedly
    • e.g. fatty acid synthesis, ?-oxidation

  4. each pathway may have branch points for metabolites to enter or leave
Last modified: Friday, 20 January 2012, 7:24 AM