ATP/ADP - Chemistry LibreTexts
I'm guessing that you know that ATP is basically a way for the cells of your body to store energy. To make things a little simpler, think of ATP as having 4 parts. A.1 ATP and ADP Cycle Develop and use models to explain how chemical reactions ATP - adenosine triphosphate supplies energy to the cell – the most important biological molecule • ATP is composed of three parts 1. Image of page 4. A.1 Develop and use models to explain how chemical reactions among ATP, ADP, its function including the ATP-ADP [adenosine diphosphate] cycle A molecule of ATP is composed of three parts bonded together by “high energy” bonds.
This makes ATP a relatively unstable molecule because it will want to give away its phosphate groups, when given the chance, in order to become a more stable molecule. The oxygen molecules of the ADP are sharing electrons. Those electrons are constantly being passed back and forth between the oxygens, creating an effect called resonance.
This stables the ADP.
UCSB Science Line
Resonance does not occur in ATP; therefore, it is a more unstable molecule. This means that it is easier for ATP to lose one of its phosphate groups.
But, it takes a large amount of water to force ADP to lose one of its phosphates. ATP is useful in many cell processes such as glycolysisphotosynthesisbeta oxidationanaerobic respirationactive transport across cell membranes as in the electron transport chainand synthesis of macromolecules such as DNA.
Macmillan Publishing Company, Some of this energy is trapped in molecules of ATP, and some is lost in the form of heat.
ATP AND BIOLOGICAL ENERGY
Each ATP molecule can then be transported elsewhere within the cell and used where needed. The energy-carrying part of an ATP molecule is the triphosphate "tail". Three phosphate groups are joined by covalent bonds. The electrons in these bonds carry energy. Within the power plants of the cell mitochondriaenergy is used to add one molecule of inorganic phosphate P to a molecule of adenosine diphosphate ADP.
ATP hydrolysis is coupled to a work-requiring energetically unfavorable process through formation of an unstable, phosphorylated intermediate, allowing the process to take place in a series of steps that are each energetically favorable. Attribution and references Attribution: Download the original article for free at http: The regeneration of ATP. In Campbell biology 10th ed.
ATP and reaction coupling
A thermodynamically unfavorable reaction can be driven by a favorable reaction. In Biochemistry 5th ed, section ATP is the main energy currency in cells. In BIOL lecture notes: