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.