Citric Acid Cycle PPT

Understanding the Citric Acid Cycle

  • Presentation by Group 3 (Torres, Rhylle; Pascual, Troy; Pancho, Nicolas; Gobasco, Rexan)

Overview of the Citric Acid Cycle (CAC)

  • Also known as the Krebs cycle.

  • Crucial metabolic pathway in cellular respiration.

  • Converts carbohydrates, fats, and proteins into carbon dioxide and water.

  • Supplies energy for ATP synthesis indirectly.

  • Plays a regulatory role in metabolite transport across the mitochondrial membrane.

  • Facilitates oxidation of carbohydrates and fatty acids.

    • References: Lanoue, 2001; Williamson & Cooper, 1980.

Functioning of the Citric Acid Cycle

  • Starts with acetyl-CoA combining with oxaloacetate to form citrate.

  • Series of enzymatic reactions oxidize citrate, releasing two CO₂ molecules.

  • Regenerates oxaloacetate: key to continuing the cycle.

  • Generates high-energy electron carriers: NADH and FADH₂.

  • These carriers fuel the electron transport chain (ETC).

  • Takes place in the mitochondrial matrix of aerobic cells.

  • Forms the metabolic core of cellular respiration.

    • References: Goodsell, 2012; Lanoue, 2001.

Inputs, Outputs, and Key Molecules

  • Inputs: Acetyl-CoA, NAD⁺, FAD, GDP, water.

  • Outputs:

    • 2 CO₂

    • 3 NADH

    • 1 FADH₂

    • 1 GTP (converted to ATP later).

  • Key intermediates: citrate, α-ketoglutarate, succinate, oxaloacetate.

  • Key enzymes: citrate synthase and isocitrate dehydrogenase.

  • Essential for both energy production and biosynthesis.

Significance and Connections

  • Pivotal in catabolism and anabolism.

  • Provides high-energy electrons for ATP synthesis.

  • Supplies precursors for biosynthesis:

    • Amino acids

    • Nucleotides

    • Fatty acids.

  • Connected to gluconeogenesis, lipid synthesis, and amino acid metabolism.

  • Highlights the cycle's importance as a metabolic hub.

    • Reference: Stenesh, 1998.

Real-World Implications

  • Maintains energy homeostasis; disruption links to metabolic disorders (e.g., diabetes, cancer).

  • Focus of biomedical research linked to health issues.

  • Applications in agriculture to enhance photosynthetic efficiency and improve crop yields.

    • Reference: Williamson & Cooper, 1980.

Conclusion

  • CAC is fundamental for cellular respiration.

  • Converts nutrients into energy and precursors for biosynthesis.

  • Generates high-energy electrons that drive ATP production.

  • Functions as a crossroads for various metabolic pathways.

Citations/References

  • Stenesh, J. (1998). The Citric Acid Cycle.

  • Goodsell, D. (2012). Citric Acid Cycle. Rcsb Protein Data Bank.

  • Lanoue, K. (2001). Citric Acid Cycle.

  • Williamson, J., & Cooper, R. (1980). Regulation of the citric acid cycle in mammalian systems.