Thermodynamic Driving Force
Thermodynamic Driving Force - Related Videos
02:38
Third Law of Thermodynamics
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2020
A pure, perfectly crystalline solid possessing no kinetic energy (that is, at a temperature of absolute zero, 0 K) may be described by a single microstate, as its purity, perfect crystallinity,and complete lack of motion means there is but one possible location for each identical atom or molecule comprising the crystal (W = 1). According to the Boltzmann equation, the entropy of this system is zero. This limiting condition for a system’s entropy represents the third law of thermodynamics: the...
02:49
Second Law of Thermodynamics
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2020
In the quest to identify a property that may reliably predict the spontaneity of a process, a promising candidate has been identified: entropy. Processes that involve an increase in entropy of the system (ΔS > 0) are very often spontaneous; however, examples to the contrary are plentiful. By expanding consideration of entropy changes to include the surroundings, a significant conclusion regarding the relation between this property and spontaneity may be reached. In thermodynamic models, the...
02:16
First Law of Thermodynamics
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2020
Energy Conservation Energy can be converted from one form into another, but all of the energy present before a change occurs always exists in some form after the change is completed. This observation is expressed in the law of conservation of energy: during a chemical or physical change, energy can be neither created nor destroyed, although it can be changed in form. According to the law of conservation of matter, there is no detectable change in the total amount of matter during a chemical...
14:03
Micro-drive Array for Chronic in vivo Recording: Drive Fabrication
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Cited by 110 •
2009
In this protocol we demonstrate how to fabricate a micro-drive array for chronic electrophysiological recordings in rats.
02:36
Electromotive Force
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2020
Electricity is generated by either electrons or ions flowing through a solution or a conducting medium. This flow of electrons or specifically electrical charge is defined as an electric current. When electrons move through a wire, they generate an electric current. It can be recalled that in a redox reaction, electrons are lost and gained. In the spontaneous redox reaction of zinc with copper, when zinc is immersed in a copper ion solution, a transfer of electrons from one substance to...
FAQs
The sign of ΔG indicates thermodynamic favorability, but it does not specify how quickly a reaction occurs. A negative value means the reaction is favorable under the stated conditions, whereas concentrations, temperature, and pressure can change the driving force. This distinction helps biologists separate the direction of energy-related change from the rate observed experimentally.
Enzymes alter reaction rates rather than the overall equilibrium or thermodynamic favorability of a reaction. Consequently, an enzyme can change how rapidly a biochemical process approaches its equilibrium state without changing whether the reaction has a favorable ΔG under specified conditions. This distinction is essential when interpreting enzyme activity in cellular pathways.
Cells couple reactions with unfavorable ΔG to favorable processes such as ATP hydrolysis. The favorable process supplies a thermodynamic contribution that helps drive the otherwise unfavorable transformation. This coupling principle explains how cells sustain energy-requiring activities rather than treating each reaction as an isolated event, and it connects ATP use with broader cellular energy flow.
Thermodynamic driving force helps determine whether movement associated with membrane transport is favorable under particular cellular conditions. Concentration and other environmental conditions affect the relevant thermodynamic potential, so the predicted direction or favorability of transport can change as those conditions change. This provides a framework for relating membrane movement to cellular energy management.
Begin by considering the reaction or process under its specified conditions, then evaluate how its Gibbs free-energy change is affected by concentration, temperature, or pressure. A negative ΔG supports thermodynamic favorability, while a different set of conditions may alter that assessment. If the process is unfavorable, examine whether coupling to a favorable reaction could support it.
The concept helps organize explanations of energy flow across metabolism, protein folding, and molecular assembly, as well as membrane transport. In each case, thermodynamic analysis relates changes in potential to the direction or favorability of a process under specified conditions. It therefore provides a common framework for interpreting diverse biological phenomena rather than only chemical reactions.