5.1 - Metabolism

Types of Metabolism in a Cell

• Metabolism: All chemical reactions that occur in a living organism.
• Metabolic processes involve:
  • converting food into energy in the form of adenosine triphosphate (ATP);
  • forming carbohydrates, proteins, lipids and nucleic acids.
• Metabolism is divided into two types:
  • Catabolism: Breakdown of complex substances into simple substances; releases energy.
    • Example: Breakdown of glucose during cellular respiration to generate energy.
    • General reaction: $A\to B+C+\text{Energy}$
  • Anabolism: Synthesis of complex molecules from simple molecules; uses or absorbs energy.
    • Example: Formation of glucose during photosynthesis.
    • General reaction: $A+B+\text{Energy}\to C$