bioenergetics Flashcards
What is the primary function of ATP in cells?
ATP acts as the primary energy currency in cells, storing and transferring energy to drive various cellular processes.
What is the free energy change (ΔG) for the hydrolysis of ATP?
The free energy change (ΔG) for the hydrolysis of ATP to ADP and inorganic phosphate (Pi) is approximately -31 kJ/mol.
What are two factors that contribute to the large free energy change during ATP hydrolysis?
Relief of electrostatic repulsion between the negatively charged phosphate groups.
Increased resonance stabilization of the products (ADP and Pi).
How does energy coupling work in metabolism?
Energy coupling involves using the energy released from exergonic reactions (e.g., ATP hydrolysis) to drive endergonic reactions (e.g., protein synthesis).
How many ATP/GTP molecules are theoretically required to form one peptide bond during protein synthesis?
Theoretically, 3 ATP/GTP molecules are used for each peptide bond formed.
Why is the actual ATP requirement for protein synthesis in whole animals ten times higher than theoretical values?
ATP is consumed in various other processes such as cellular maintenance, amino acid synthesis, active transport of nutrients, and protein turnover.
What is the relationship between the oxidation of foodstuffs and ATP formation?
The oxidation of foodstuffs (e.g., glucose) releases energy, which can be coupled to ATP formation to store and transfer energy for cellular processes.
What is the standard free energy change (ΔG°) for the complete oxidation of glucose to CO₂ and H₂O?
The standard free energy change (ΔG°) for the oxidation of glucose is approximately -2870 kJ/mol.
What role do redox reactions play in ATP generation?
Redox reactions transfer electrons between molecules, and the energy released from these reactions is used to generate ATP, especially in the electron transport chain.
What is the Nernst equation used for?
The Nernst equation calculates the actual redox potential (E) of a reaction based on the concentrations of oxidized and reduced species.
What is the formula for calculating free energy from the redox potential?
ΔG° = -nFΔE°
(where n = number of electrons transferred, F = Faraday constant, ΔE° = redox potential difference between two couples)
How does the electron transport chain (ETC) generate ATP?
The ETC transfers electrons from NADH and FADH₂ to oxygen, releasing energy that is used to pump protons across the mitochondrial membrane, creating a proton gradient that drives ATP synthesis.
What is the typical free energy change when NADH is oxidized in the ETC?
The free energy change when NADH is oxidized is approximately -220 kJ/mol.
Why is energy “wasted” in the electron transport chain?
Some energy is lost in the ETC to ensure the reaction proceeds in one direction, making the process irreversible, which is necessary for efficient ATP production.
What is the difference between equilibrium and non-equilibrium thermodynamics?
What is the difference between equilibrium and non-equilibrium thermodynamics?
