BIOENERGETICS

1. Metabolism/Bioenergetics

  • Metabolism is the set of life-sustaining chemical reactions in organisms, transforming food into energy. Bioenergetics explores energy flow through biological systems.

2. Components of the Cell

  • Cells consist of:

    • Cell membrane

    • Cytoplasm

    • Nucleus

    • Organelles (e.g., mitochondria, endoplasmic reticulum, Golgi apparatus)

3. Endergonic vs. Exergonic Reactions

  • Endergonic reactions absorb energy, while exergonic reactions release energy.

  • Oxidation is the loss of electrons, and reduction is the gain of electrons.

4. Activation Energy and Enzymes

  • Activation Energy: The minimum energy required to initiate a chemical reaction.

  • Enzymes lower activation energy, speeding up reactions (e.g., catalase speeds decomposition of hydrogen peroxide).

  • Enzyme activity can be affected by temperature, pH, and substrate concentration.

5. ATP Function in the Body

  • ATP (adenosine triphosphate) serves as the primary energy carrier in cells, fueling various biological processes.

6. Biological Work Requiring ATP

  • Muscle contraction

  • Active transport

  • Synthesis of molecules (e.g., proteins, nucleic acids)

7. ATP Generation Methods

  • 3 Main Energy Systems:

    • Phosphagen System: Quick energy (immediate);

    • Anaerobic Glycolysis: Short bursts (2 minutes);

    • Aerobic System: Long-term, efficient (generates most ATP).

  • Phosphagen system activates first, aerobic system has the largest ATP capacity.

8. Importance of Acetyl CoA

  • Acetyl CoA is crucial for energy production and metabolic pathways.

  • Universal Intermediate: It plays a pivotal role in various biochemical reactions, linking carbohydrate, fat, and protein metabolism.

9. Potential Energy from Krebs Cycle

  • Produces NADH and FADH2, which store energy for use in the electron transport chain.

10. Importance of O2

  • O2 is essential for aerobic respiration, enabling efficient ATP production via oxidative phosphorylation.

11. Electron Transport Chain (ETC)

  • The ETC creates a proton gradient across the mitochondrial membrane, facilitating ATP synthesis.

  • Produces about 2.5 ATP per NADH and 1.5 ATP per FADH2.

12. Beta Oxidation

  • A process that breaks down fatty acids, yielding Acetyl CoA and reducing equivalents (NADH and FADH2), thus producing many ATPs due to high energy content.

13. Protein Usage for Energy

  • Proteins are generally not used for energy unless carbohydrates and fats are insufficient, primarily serving structural functions.

14. Energy System for Physical Activities

  • Sprinting: Primarily utilizes the phosphagen system and anaerobic glycolysis for immediate and short-term energy.

15. Anaerobic vs. Aerobic Glycolysis

  • Anaerobic Glycolysis: Occurs without oxygen, resulting in lactic acid production.

  • Aerobic Glycolysis: Occurs with oxygen, leading to complete glucose oxidation.

16. Fat vs. Carbohydrate Efficiency

  • Fat provides more ATP per molecule than carbohydrates due to its higher carbon content and energy density.

17. Storage of Glucose and Fat

  • Glucose: Stored as glycogen in the liver and muscles.

  • Fats: Stored as triglycerides in adipose tissue.

18. Location of Anaerobic and Aerobic Metabolism

  • Anaerobic Metabolism: Occurs in the cytoplasm.

  • Aerobic Metabolism: Occurs in the mitochondria.

  • The location impacts energy efficiency and the type of ATP production.

19. Importance of NADH and FADH2

  • They are electron carriers that transfer electrons to the ETC, driving ATP production.

20. ATP Count from Energy Systems

  • Immediate System: Produces 1 ATP per reaction.

  • Anaerobic Glycolysis: Generates 2 ATP per glucose molecule.

  • Aerobic Glycolysis: Yields 30-32 ATP per glucose molecule.

21. Glycogenolysis vs. Gluconeogenesis

  • Glycogenolysis: Breakdown of glycogen into glucose.

  • Gluconeogenesis: Formation of glucose from non-carbohydrate sources.

22. Components of a Triglyceride

  • Comprised of glycerol and three fatty acid chains.

23. Key Enzymes

  • Notable enzymes in the phosphocreatine system and glycolysis include creatine kinase and phosphofructokinase respectively.