Overview of Cellular Metabolism Processes

Aug 24, 2024

Lecture Notes: Cellular Metabolism and Metabolic Pathways

Introduction

  • Review of previous lecture: cell structure, organelles, and chemistry.
  • Focus of this lecture: Cellular Metabolism (Metabolic Pathways).
  • Cellular metabolism provides energy to the cell like gasoline to a car.

Key Processes in Cellular Metabolism

Glycolysis

  • Definition: Breakdown of glucose by enzymes.
    • Glyco = Sugar/Glucose
    • Lysis = Breakdown
  • Products: ATP and pyruvic acid.
  • Process:
    • Begins with glucose, using ATP to break it down.
    • Produces 2 ATP for every glucose molecule.
    • Fast process.
  • Importance: Initial step in energy production.

Krebs Cycle (Citric Acid Cycle)

  • Occurs in Mitochondria (specifically in the matrix).
  • Function: Utilizes pyruvate from glycolysis to produce ATP.
  • Process:
    • Acetyl CoA is derived from pyruvate.
    • Cycle of reactions rearranging molecules, releasing ATP, CO2, water.
  • Produces additional 2 ATP per glucose molecule.

Mitochondria Structure

  • Description: Rod or oval-shaped organelle with double membrane.
  • Features:
    • Outer and inner bilipid membrane.
    • Krebs cycle occurs in the matrix.
  • Importance in Metabolism: Houses essential processes for ATP production.

Electron Transport Chain (ETC) / Oxidative Phosphorylation

  • Final process in the metabolic pathway.
  • Location: Inner membrane of the mitochondria.
  • Process:
    • Involves electron exchange and bond rearrangement.
    • Uses four protein complexes to create ATP.
  • Output: Produces 34 ATP from byproducts of glycolysis and the Krebs cycle.
  • Characteristics:
    • Slow process but highly efficient in ATP production.

Summary of Metabolic Pathways

  • Overall ATP Production: 38 ATP per glucose molecule (Glycolysis + Krebs Cycle + ETC).
  • Efficiency:
    • Glycolysis - Fast but less ATP.
    • Krebs Cycle - Moderate speed.
    • ETC - Slow but most ATP.
  • Different cells/tissues may rely on different parts of the pathways depending on energy needs.

Additional Notes

  • Other molecules like proteins and triglycerides can also be used for ATP production.
  • Glucose is the most efficient fuel source.
  • Future discussions will cover how different tissues utilize various metabolic pathways.

This lecture provided a detailed overview of cellular energy production through metabolic pathways like glycolysis, the Krebs cycle, and the electron transport chain. Understanding these processes is crucial for grasping how cells harness energy efficiently.