Human Anatomy and Physiology 1: Control of Metabolic Reactions

Lecture Overview

• Instructor: Jessica Medrano
• Focus: Control of metabolic reactions, specifically the regulation of metabolic pathways.

Introduction to Metabolic Pathways

• Importance of Energy: Human beings need energy, obtained from food digestion.
• Metabolic Processes: Involve chemical reactions within cells controlled by enzymes.
  • Examples: Glycolysis, Kreb's cycle, Electron transport chain.

Understanding Metabolic Pathways

• Definition: Series of enzyme-controlled reactions leading to the formation of a product.
  • Results in synthesis or breakdown of biochemicals.
• Visual Aid: Diagrams typically show reactions with arrows, each controlled by enzymes.

Regulation of Metabolic Pathways

• Regulatory Enzymes: Catalyze one step in the pathway, setting the reaction sequence rate.
  • Molecule Limitation: Enzymes have limited molecules and can become saturated.
  • Rate-Limiting Enzyme: Occurs when enzyme activity, not substrate concentration, limits reaction rate.
  • Position: Often found at the beginning of the reaction sequence.

Negative Feedback in Metabolic Pathways

• Mechanism: Pathway products inhibit rate-limiting enzymes when in excess.
• Process:
  • Buildup: Product accumulation stops further synthesis by inhibiting enzymes.
  • Decrease: Lower product concentration reactivates the enzyme, producing more product.

Conclusion

• Key Takeaway: Understanding how metabolic pathways are regulated is crucial for grasping how energy and biochemicals are managed in the body.
• Health Advice: Stay safe and wear a mask.