Metabolism

Metabolism refers to the sum of all life-sustaining chemical reactions that occur within the cells of living organisms. These processes are divided into two main categories: catabolism, the breakdown of complex molecules (like food) to release energy, and anabolism, the use of that energy to synthesize complex components like proteins and nucleic acids for growth and repair. As a central process in biology, metabolism is responsible for converting nutrients into usable cellular energy (ATP) and is intricately regulated by the endocrine system, where hormones control the rate and direction of these pathways to maintain the body's energy balance and internal stability.

1. Introduction to Metabolism
   1. Defining Metabolism
      1. Basic Definition and Scope
      2. Metabolic Pathways Overview
      3. Cellular Compartmentalization of Metabolism
   2. Anabolism
      1. Definition and Characteristics
      2. Energy Requirements
      3. Building Complex Molecules
      4. Examples of Anabolic Processes
   3. Catabolism
      1. Definition and Characteristics
      2. Energy Release
      3. Breaking Down Complex Molecules
      4. Examples of Catabolic Processes
   4. Interrelationship Between Anabolism and Catabolism
      1. Metabolic Balance
      2. Coordinated Regulation
      3. Energy Coupling