Dictionary > Chemiosmotic coupling hypothesis

Chemiosmotic coupling hypothesis

Definition
noun
A theory postulated by the biochemist Peter Mitchell in 1961 to describe ATP synthesis by way of a proton electrochemical coupling.
Accordingly, hydrogen ions (protons) are pumped from the mitochondrial matrix to the intermembrane space via the hydrogen carrier proteins while the electrons are transferred along the electron transport chain in the mitochondrial inner membrane. As the hydrogen ions accumulate in the intermembrane space, an energy-rich proton gradient is established. As the proton gradient becomes sufficiently intense the hydrogen ions tend to diffuse back to the matrix (where hydrogen ions are less) via the ATP synthase (a transport protein). As the hydrogen ions diffuse (through the ATP synthase) energy is released which is then used to drive the conversion of ADP to ATP (by phosphorylation).
Supplement
This theory was not previously well accepted until a great deal of evidence for proton pumping by the complexes of the electron transfer chain emerged. This began to favor the chemiosmotic hypothesis, and in 1978, Peter Mitchell was awarded the Nobel Prize in Chemistry.
Also called: chemiosmotic hypothesis
See also: chemiosmosis, mitochondrion


You will also like...

DNA carries genes coding for proteins
Genetic Information and Protein Synthesis

Genes are expressed through the process of protein synthesis. This elaborate tutorial provides an in-depth review of the..

Ecological Research Measuring & Analysis
Ecological Research: Measuring & Analysis

This lesson is about the methods used for ecological research, such as quadrat and transect sampling, canopy fogging, an..

Photosynthesis and respiration
Plant Metabolism

Plants are responsible for incredible feats of molecular transformation. Plant processes, such as photosynthesis, photop..

Lotic community of algal species
Lotic Communities & Algae

Lotic communities have conditions that are rather harsh for typical plants. Thus, the diversity of plant species in loti..

Energy pyramid
Freshwater Community Energy Relationships – Producers & Consumers

This tutorial looks at the relationship between organisms. It also explores how energy is passed on in the food chain an..

An artistic depiction of a human embryo
Growth and Development of a Human Baby

Upon fertilization, a zygote forms and develops into an embryo. This tutorial elaborates on the growth and development f..