38 Questions
What is the fundamental principle of thermodynamics that states the total energy of a system remains constant?
First Law of Thermodynamics
What is the relationship between ∆G° and Keq?
ΔG° = −RT lnKeq
What type of reaction is characterized by a negative ∆G°?
Exergonic reaction
What is the purpose of coupling an exergonic reaction to an endergonic reaction?
To make the endergonic reaction spontaneous
What term is used to describe the breakdown or oxidation of fuel molecules?
Catabolism
What is the term for the process of building up substances in a cell?
Anabolism
What is the overall net change in a coupled exergonic-endergonic system?
Exergonic
What is the term for the combination of catabolic and anabolic processes?
Metabolism
What is the purpose of ATP in bioenergetics?
To store energy
What is the role of the equilibrium constant in bioenergetics?
To regulate the concentration of reactants and products
What is the main purpose of coupling dehydrogenation and hydrogenation reactions by an intermediate carrier?
To transfer free energy from an exergonic to an endergonic reaction
What type of bonds are present in ATP?
High-energy anhydrate bonds and low-energy ester bonds
What is the reason for the high free-energy change on hydrolysis of ATP?
Relief of charge repulsion between negatively charged oxygen atoms
What is the main function of the ATP/ADP cycle?
To connect energy-generating processes to energy-utilizing processes
What is the structure of ATP?
A nucleotide with three phosphate groups
Why is the phosphate bond in AMP considered a low-energy bond?
Because it is a normal ester link
What is the significance of high-energy phosphate groups in energy capture and transfer?
They play a central role in energy capture and transfer
What is the difference between ATP and ADP?
ATP has three phosphate groups, while ADP has one
What is the role of the intermediate carrier in the coupling of exergonic and endergonic reactions?
To transfer free energy from the exergonic reaction to the endergonic reaction
What is the primary function of the high-energy intermediate compound in the coupling of exergonic and endergonic reactions?
To transfer free energy from the exergonic to the endergonic reaction
What type of bond is present in the high-energy phosphate groups of ATP?
Anhydrate bond
What is the result of the hydrolysis of ATP?
Release of free energy and stabilization of reaction products
What is the primary role of ATP in the cell?
To transfer free energy from exergonic to endergonic reactions
What is the purpose of the ATP/ADP cycle?
To connect energy-generating and energy-utilizing processes
What is the characteristic of the phosphate bond in AMP?
Low-energy ester bond
What is the significance of the structure of ATP?
It enables the transfer of free energy from exergonic to endergonic reactions
What is the role of charge repulsion in the high free-energy change on hydrolysis of ATP?
It increases the free energy change
What is the purpose of synthesizing a high-energy intermediate compound in the exergonic reaction?
To transfer free energy to the endergonic reaction
What is the implication of the second law of thermodynamics in biological systems?
The total entropy of a system must increase if a process is to occur spontaneously.
What is the primary function of ATP in bioenergetic systems?
To provide energy for cellular processes.
In an exergonic reaction, what happens to the energy?
It is released.
What is the result of coupling an exergonic reaction to an endergonic reaction?
The endergonic reaction becomes more spontaneous.
What is the primary difference between catabolic and anabolic reactions?
Catabolic reactions release energy, while anabolic reactions require energy.
What is the role of ATP in catabolic reactions?
To store energy released from the reaction.
What is the significance of the equilibrium constant (Keq)?
It indicates the relative concentrations of reactants and products at equilibrium.
What is the relationship between ∆G° and the spontaneity of a reaction?
A positive ∆G° indicates a non-spontaneous reaction.
What is the role of thermodynamics in bioenergetic systems?
To predict the direction and spontaneity of chemical reactions.
What is the purpose of studying bioenergetics?
To understand how cells generate and utilize energy.
Study Notes
Coupling of Dehydrogenation and Hydrogenation Reactions
- Transfer of free energy from an exergonic to an endergonic reaction occurs via a high-energy intermediate compound.
- This process allows the coupling of an exergonic to an endergonic reaction, enabling the transfer of free energy from one pathway to another.
Adenosine Triphosphate (ATP)
- ATP is a high-energy intermediate compound that plays a central role in energy capture and transfer in living cells.
- ATP is a nucleotide consisting of adenosine (adenine linked to ribose) and three phosphate groups.
- ATP contains two high-energy phosphate groups, while ADP contains one, and AMP contains a low-energy phosphate group.
- The high free-energy change on hydrolysis of ATP is due to relief of charge repulsion and stabilization of reaction products.
ATP/ADP Cycle
- The ATP/ADP cycle connects processes that generate ATP to those that utilize ATP, continuously consuming and regenerating ATP.
Biologic Systems and Thermodynamics
- Biologic systems conform to the general laws of thermodynamics, including the laws of energy conservation and entropy increase.
- The total energy of a system, including its surroundings, remains constant, and the total entropy of a system must increase if a process is to occur spontaneously.
The Equilibrium Constant
- The equilibrium constant gives the relative concentration of reactants and products at equilibrium.
- The relationship between ΔG° and Keq is: ΔG° = −RT lnKeq.
Exergonic and Endergonic Reactions
- ΔG° negative: exergonic reaction (spontaneous)
- ΔG° positive: endergonic reaction (non-spontaneous)
Catabolic and Anabolic Reactions
- Catabolic reactions are exergonic (breakdown or oxidation of fuel molecules) and anabolic reactions are endergonic (synthetic reactions that build up substances).
- The combined catabolic and anabolic processes constitute metabolism.
Coupling of Dehydrogenation and Hydrogenation Reactions
- Transfer of free energy from an exergonic to an endergonic reaction occurs via a high-energy intermediate compound.
- This process allows the coupling of an exergonic to an endergonic reaction, enabling the transfer of free energy from one pathway to another.
Adenosine Triphosphate (ATP)
- ATP is a high-energy intermediate compound that plays a central role in energy capture and transfer in living cells.
- ATP is a nucleotide consisting of adenosine (adenine linked to ribose) and three phosphate groups.
- ATP contains two high-energy phosphate groups, while ADP contains one, and AMP contains a low-energy phosphate group.
- The high free-energy change on hydrolysis of ATP is due to relief of charge repulsion and stabilization of reaction products.
ATP/ADP Cycle
- The ATP/ADP cycle connects processes that generate ATP to those that utilize ATP, continuously consuming and regenerating ATP.
Biologic Systems and Thermodynamics
- Biologic systems conform to the general laws of thermodynamics, including the laws of energy conservation and entropy increase.
- The total energy of a system, including its surroundings, remains constant, and the total entropy of a system must increase if a process is to occur spontaneously.
The Equilibrium Constant
- The equilibrium constant gives the relative concentration of reactants and products at equilibrium.
- The relationship between ΔG° and Keq is: ΔG° = −RT lnKeq.
Exergonic and Endergonic Reactions
- ΔG° negative: exergonic reaction (spontaneous)
- ΔG° positive: endergonic reaction (non-spontaneous)
Catabolic and Anabolic Reactions
- Catabolic reactions are exergonic (breakdown or oxidation of fuel molecules) and anabolic reactions are endergonic (synthetic reactions that build up substances).
- The combined catabolic and anabolic processes constitute metabolism.
This quiz covers the concept of coupling dehydrogenation and hydrogenation reactions via an intermediate carrier, transferring free energy from an exergonic to an endergonic reaction.
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