Chapter Two Lecture: Metabolism

Introduction to Metabolism

• Metabolism involves all chemical reactions in the body.
• It's not just about calories consumed and calories burned.
• Two main types of metabolic processes:
  • Anabolism: Synthesis or making reactions.
  • Catabolism: Breaking down or decomposition reactions.

Energy Concepts

• Energy: The ability to perform work.
  • Kinetic Energy: Energy of motion.
  • Potential Energy: Stored energy, often in chemical bonds.
• Chemical reactions may:
  • Release energy (exergonic)
  • Absorb energy (endergonic)
• Examples:
  • Exergonic: Burning wood, Hot Hands
  • Endergonic: Automatic cold compress

Activation Energy

• Energy required for a reaction to occur.
• Discussed further in the context of enzymes.

Writing Chemical Reactions

• Format: Reactants on the left, Products on the right.
• Reactions can be categorized:
  • Anabolic or catabolic based on direction.
  • Endergonic or exergonic based on energy released or absorbed.

Factors Influencing Reaction Rate

1. Temperature: Not variable in the body to avoid damage.
2. Concentration: More reactants lead to more products.
3. Surface Area: Smaller molecules react quicker.
4. Enzymes: Act as catalysts and lower activation energy.

Enzymes

• Function as catalysts to speed up reactions.
• Bring reactants (A + B) closer to reduce required energy.
• Not consumed in the reaction.
• Each reaction in the body has a specific enzyme.

Summary

• Metabolism is a broad concept covering all body reactions.
• Understanding energy transformations and reactions is crucial.
• Enzymes play a critical role in facilitating reactions.