30 Questions
What is the role of AMP in a cell?
An energy sensor and regulator of metabolism
What is the function of hydrolytic cleavage of ATP's 'high energy' bonds?
To couple with energy-requiring reactions
What is the purpose of designing ATP analogs like AMPPNP?
To study the dependence of coupled reactions on ATP hydrolysis
What is the function of phosphocreatine (creatine phosphate)?
To store energy in nerve and muscle cells
What is the role of AMP-Activated Protein Kinase?
To mediate some regulatory effects of AMP
What is the structure of inorganic polyphosphate?
A chain of phosphate residues linked by phosphoanhydride bonds
What is the definition of energy in biological systems?
The ability to do work
What does the Gibbs Free Energy (∆G) represent?
The difference between the energy contained in the products and reactants of a reaction
What is the relation between the changes of free energy (∆G), enthalpy (∆H), and entropy (∆S)?
∆G = ∆H - T∆S
What is the significance of a negative ∆G value?
The reaction is spontaneous and exergonic
What is the term for the change in the randomness of a system?
Entropy (∆S)
What happens to the entropy of a system at reaction equilibrium?
It attains a maximum
What is the relationship between ∆Gº' and K'eq?
∆Gº' is equal to -RT ln K'eq
At what ∆Gº' value is a reaction at equilibrium?
∆Gº' = 0 kJ/mol
What is the purpose of energy coupling in vital processes?
To obtain energy from oxidative reactions
What is the result of summing the free energy changes of half-reactions in a coupled reaction?
The free energy of the coupled reaction
What is the role of a common intermediate in energy coupling?
To couple two separate reactions in the same cellular compartment
What is the ∆Gº' value of the coupled reaction catalyzed by Hexokinase?
-17 kJ/mol
What is the overall spontaneous reaction in the example involving PPi?
A + ATP + H2O → B + AMP + 2 Pi
What is the function of Pyrophosphatase enzyme?
To drive the reaction for which PPi is a product
What type of bonds are represented by the '~' symbol?
Phosphoanhydride bonds
What is the characteristic of 'high energy' bonds?
Large negative ∆G of hydrolysis
What is the potential of compounds with 'high energy bonds'?
To have high group transfer potential
What is the maximum number of ~P bonds that can be cleaved from ATP?
2
What is the result of phosphodiesterase catalyzing the hydrolytic cleavage of one Pi ester?
Converting cAMP → 5'-AMP
What is the characteristic of cAMP that makes it a good transient signal?
Its lability to hydrolysis
What is the direction of electron flow in oxidation reactions?
From reductants to molecular oxygen
What is the effect of increased oxidation of a C atom?
Increased number of C-O bonds
What is the role of NAD+ in metabolic pathways?
Electron acceptor in catabolic pathways
What is the result of the evolution of photosynthesis?
Increase in oxygen levels
Learn about the definition and basics of bioenergetics, including the concept of Gibbs Free Energy and how it relates to energy transfer and utilization in biological systems.
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