Bioenergetics Definition and Basics

What is the role of AMP in a cell?

A molecule that inhibits metabolic pathways
An energy source
An energy sensor and regulator of metabolism (correct)
A molecule that stores energy

What is the function of hydrolytic cleavage of ATP's 'high energy' bonds?

To inhibit metabolic pathways
To couple with energy-requiring reactions (correct)
To store energy
To synthesize proteins

What is the purpose of designing ATP analogs like AMPPNP?

To study the dependence of coupled reactions on ATP hydrolysis (correct)
To store energy in cells
To inhibit ATP production
To stimulate metabolic pathways

What is the function of phosphocreatine (creatine phosphate)?

To store energy in nerve and muscle cells (A) Signup and view all the answers

What is the role of AMP-Activated Protein Kinase?

To mediate some regulatory effects of AMP (D) Signup and view all the answers

What is the structure of inorganic polyphosphate?

A chain of phosphate residues linked by phosphoanhydride bonds (C) Signup and view all the answers

What is the definition of energy in biological systems?

The ability to do work (B) Signup and view all the answers

What does the Gibbs Free Energy (∆G) represent?

The difference between the energy contained in the products and reactants of a reaction (D) Signup and view all the answers

What is the relation between the changes of free energy (∆G), enthalpy (∆H), and entropy (∆S)?

∆G = ∆H - T∆S (D) Signup and view all the answers

What is the significance of a negative ∆G value?

The reaction is spontaneous and exergonic (A) Signup and view all the answers

What is the term for the change in the randomness of a system?

Entropy (∆S) (C) Signup and view all the answers

What happens to the entropy of a system at reaction equilibrium?

It attains a maximum (B) Signup and view all the answers

What is the relationship between ∆Gº' and K'eq?

∆Gº' is equal to -RT ln K'eq (D) Signup and view all the answers

At what ∆Gº' value is a reaction at equilibrium?

∆Gº' = 0 kJ/mol (B) Signup and view all the answers

What is the purpose of energy coupling in vital processes?

To obtain energy from oxidative reactions (D) Signup and view all the answers

What is the result of summing the free energy changes of half-reactions in a coupled reaction?

The free energy of the coupled reaction (D) Signup and view all the answers

What is the role of a common intermediate in energy coupling?

To couple two separate reactions in the same cellular compartment (C) Signup and view all the answers

What is the ∆Gº' value of the coupled reaction catalyzed by Hexokinase?

-17 kJ/mol (D) Signup and view all the answers

What is the overall spontaneous reaction in the example involving PPi?

A + ATP + H2O → B + AMP + 2 Pi (C) Signup and view all the answers

What is the function of Pyrophosphatase enzyme?

To drive the reaction for which PPi is a product (D) Signup and view all the answers

What type of bonds are represented by the '~' symbol?

Phosphoanhydride bonds (C) Signup and view all the answers

What is the characteristic of 'high energy' bonds?

Large negative ∆G of hydrolysis (B) Signup and view all the answers

What is the potential of compounds with 'high energy bonds'?

To have high group transfer potential (A) Signup and view all the answers

What is the maximum number of ~P bonds that can be cleaved from ATP?

2 (C) Signup and view all the answers

What is the result of phosphodiesterase catalyzing the hydrolytic cleavage of one Pi ester?

Converting cAMP → 5'-AMP (B) Signup and view all the answers

What is the characteristic of cAMP that makes it a good transient signal?

Its lability to hydrolysis (D) Signup and view all the answers

What is the direction of electron flow in oxidation reactions?

From reductants to molecular oxygen (A) Signup and view all the answers

What is the effect of increased oxidation of a C atom?

Increased number of C-O bonds (C) Signup and view all the answers

What is the role of NAD+ in metabolic pathways?

Electron acceptor in catabolic pathways (A) Signup and view all the answers

What is the result of the evolution of photosynthesis?

Increase in oxygen levels (D) Signup and view all the answers