Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Potential Energy00:52

Potential Energy

The energy stored by a structure and location of matter in space is called potential energy. For instance, raising a kettlebell changes its spatial location and increases its potential energy. Similarly, a stretched rubber band contains potential energy which, under certain conditions, can be converted into other forms of energy, such as kinetic energy.
Chemical bonds that form attractive forces between atoms also contain potential energy, called chemical energy. When a chemical reaction...
Free Energy01:21

Free Energy

Free energy—abbreviated as G for the scientist Gibbs who discovered it—is a measurement of useful energy that can be extracted from a reaction to do work. It is the energy in a chemical reaction that is available after entropy is accounted for. Reactions that take in energy are considered endergonic and reactions that release energy are exergonic. Plants carry out endergonic reactions by taking in sunlight and carbon dioxide to produce glucose and oxygen. Animals, in turn, break down the...
The First Law of Thermodynamics01:13

The First Law of Thermodynamics

The first law of thermodynamics deals with the total amount of energy in the universe. It states that this total amount of energy is constant. In other words, there has always been, and always will be, exactly the same amount of energy in the universe. Energy exists in many different forms. According to the first law of thermodynamics, energy may transfer from place to place or transform into different forms, but it cannot be created or destroyed. The transfers and transformations of energy...
ATP Energy Storage and Release01:31

ATP Energy Storage and Release

ATP is a highly unstable molecule. Unless quickly used to perform work, ATP spontaneously dissociates into ADP and inorganic phosphate (Pi), and the free energy released during this process is lost as heat. The energy released by ATP hydrolysis is used to perform work inside the cell and depends on a strategy called energy coupling. Cells couple the exergonic reaction of ATP hydrolysis with endergonic reactions, allowing them to proceed.
One example of energy coupling using ATP involves a...
Coupled Reactions01:17

Coupled Reactions

Cellular processes such as building and breaking down complex molecules occur through stepwise chemical reactions. Some of these chemical reactions are spontaneous and release energy, whereas others require energy to proceed. Cells often couple the energy-releasing reaction with the energy-requiring one to carry out important cell functions. 
Energy in adenosine triphosphate or ATP molecules is easily accessible to do work. ATP powers the majority of energy-requiring cellular reactions. Cells...
ATP Energy Storage and Release01:31

ATP Energy Storage and Release

ATP is a highly unstable molecule. Unless quickly used to perform work, ATP spontaneously dissociates into ADP and inorganic phosphate (Pi), and the free energy released during this process is lost as heat. The energy released by ATP hydrolysis is used to perform work inside the cell and depends on a strategy called energy coupling. Cells couple the exergonic reaction of ATP hydrolysis with endergonic reactions, allowing them to proceed.
One example of energy coupling using ATP involves a...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Uncoupled active transport mechanisms accounting for low selectivity in multidrug carriers: P-glycoprotein and SMR antiporters.

The Journal of membrane biology·1999
Same author

Limits on the tightness of coupling in active transport.

The Journal of membrane biology·1999
Same author

Force generation, work, and coupling in molecular motors.

Biophysical journal·1996
Same author

Interpreting the effects of specific protein modification on antiport coupling mechanisms: the case of the aspartate/glutamate exchanger.

Biochimica et biophysica acta·1995
Same author

Interpreting the effects of site-directed mutagenesis on active transport systems.

Biochimica et biophysica acta·1994
Same author

The application of vectorial coupling theory to the calcium pump.

Biochimica et biophysica acta·1994

Related Experiment Video

Updated: Jul 15, 2026

High-Resolution Respirometry to Assess Bioenergetics in Cells and Tissues Using Chamber- and Plate-Based Respirometers
09:53

High-Resolution Respirometry to Assess Bioenergetics in Cells and Tissues Using Chamber- and Plate-Based Respirometers

Published on: October 26, 2021

Channelling free energy into work in biological processes

R M Krupka1

  • 1Agriculture Canada, London, Ontario, Canada. krupka@sscl.uwo.ca

Experimental Physiology
|May 6, 1998
PubMed
Summary

Free energy from ATP or ion gradients powers cellular work through substrate binding energy. This binding energy dictates the efficiency of coupled reactions, limiting molecular motor force and protein conformational changes.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Biophysics

Background:

  • Cellular processes like osmotic work and mechanical work are driven by free energy from ATP or ion gradients.
  • Molecular motors and membrane pumps utilize these energy sources to perform cellular functions.
  • The mechanisms underlying energy coupling and force generation in these systems are complex and involve protein dynamics.

Purpose of the Study:

  • To explain the mechanisms of energy coupling and force generation by molecular motors and membrane pumps.
  • To derive a general expression for the switching between coupled and uncoupled reaction pathways.
  • To establish the relationship between substrate binding energy and the work/force output of biological machines.

Main Methods:

  • Analysis of reaction sequences involving coupled and uncoupled paths.

More Related Videos

Characterizing Mediated Extracellular Electron Transfer in Lactic Acid Bacteria with a Three-Electrode, Two-Chamber Bioelectrochemical System
10:23

Characterizing Mediated Extracellular Electron Transfer in Lactic Acid Bacteria with a Three-Electrode, Two-Chamber Bioelectrochemical System

Published on: August 23, 2024

Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors
10:44

Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors

Published on: January 31, 2025

Related Experiment Videos

Last Updated: Jul 15, 2026

High-Resolution Respirometry to Assess Bioenergetics in Cells and Tissues Using Chamber- and Plate-Based Respirometers
09:53

High-Resolution Respirometry to Assess Bioenergetics in Cells and Tissues Using Chamber- and Plate-Based Respirometers

Published on: October 26, 2021

Characterizing Mediated Extracellular Electron Transfer in Lactic Acid Bacteria with a Three-Electrode, Two-Chamber Bioelectrochemical System
10:23

Characterizing Mediated Extracellular Electron Transfer in Lactic Acid Bacteria with a Three-Electrode, Two-Chamber Bioelectrochemical System

Published on: August 23, 2024

Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors
10:44

Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors

Published on: January 31, 2025

  • Derivation of expressions for coupling tightness based on substrate dissociation constants.
  • Estimation of dissociation constant ratios from published data on molecular motor forces.

    • Main Results:

    • Coupling tightness is limited by the ratio of substrate dissociation constants before and after conformational changes.
    • External work performed by molecular motors is constrained by this ratio: W = Fd < RT ln(Kinitial state/Kfinal state).
    • High ratios (>10^4) were observed for myosin, kinesin, and the red cell anion exchange carrier, suggesting significant binding energy contributions.

    Conclusions:

    • Substrate binding energy is a key determinant of energy coupling and force generation in biological systems.
    • The efficiency of coupled reactions is modulated by abrupt alterations in protein mobility and specificity.
    • The force developed by ATP-driven motors is independent of the ATP reaction itself and originates from substrate binding energy.