Because the overall free-energy change for coupled reactions equals the sum of the individual free energy changes, a thermodynamically unfavorable reaction, such as a typical biochemical processes, can be driven by a thermodynamically favorable reaction coupled to it, such as the cleavage of ATP. The activities of many protein enzymes are coupled to ATP hydrolysis. However, a few other compounds in biological systems have to capacity to carry out phosphate hydrolysis with even greater negative free energy than ATP, such as phosphoenolpyruvate, acetyl phosphate, and phosphocreatine, which means that these substances have the ability to transfer a phosphate group to ADP. ATP releases its free energy coupled to biochemical processes and recharges coupled to the hydrolysis of such molecules as phosphoenolpyruvate.












The WikiPremed MCAT Course is a comprehensive course in the undergraduate level general sciences. Undergraduate level physics, chemistry, organic chemistry and biology are presented by this course as a unified whole within a spiraling curriculum. Please read our policies on Privacy and Shipping & Returns.  Contact Us. MCAT is a registered trademark of the Association of American Medical Colleges, which does not endorse the WikiPremed Course. WikiPremed offers the customers of our publications or our teaching services no guarantees regarding eventual performance on the MCAT.


Creative Commons License
WikiPremed is a trademark of Wisebridge Learning Systems LLC. The work of WikiPremed is published under a Creative Commons Attribution NonCommercial ShareAlike License. There are elements of work here, such as a subset of the images in the archive from WikiPedia, that originated as GNU General Public License works, so take care to follow the unique stipulations of that license in printed reproductions.