How does ATP drive endergonic compoubds?

Answer 1

ATP is metastable (a thermodynamically unstable compound that does not rapidly break down in absence of a catalyst) and is commonly referred to as "free energy currency." Like monetary currency, ATP is used to provide energy in a wide variety of metabolic reactions and is universal among cells. Nevertheless, the energy content of ATP is not significantly different from other nucleoside di- and tri-phosphates. For whatever reason, however, evolution has created an array of enzymes that preferentially bind ATP and use its free energy of hydrolysis to drive endergonic reactions. Hydrolysis of either phosphoanhydride bond in ATP has a of about -31 kJ/mol. Be aware, however, that utilization of that energy to drive endergonic reactions usually does NOT involve hydrolysis of ATP. Instead, ATPbreakdown is usually coupled with a thermodynamically unfavorable reaction. In glycolysis, for example, ATP energy is used to synthesize glucose-6-phosphate from glucose. In this case, the phosphate is transferred directly from ATP to glucose to form glucose-6-phosphate.

Because ATP can transfer a phosphate group, we say that ATP has a high "phosphoryl group transfer potential" rather than calling it a high energy compound. The phosphate anhydride bonds of ATP, ADP, or pyrophosphate have relatively high values. In fact, they are roughly twice as high as the phosphate ester bonds of glucose-6-phosphate or AMP (see also - Figure 3.8). There are, however, cellular compounds with even higher phosphoryl group transfer potentials thanATP. For example, the for breakdown of phosphoenolpyruvate (PEP), 1,3-bisphosphoglycerate, and creatine phosphate are -62, -49, and -43 kJ/mol, respectively. Although the breakdown of "super-high-energy" compounds, such as PEP, is not used routinely in cells to drive endergonic reactions, these compounds are still important because they can be used to drive the synthesis of ATP from ADP + Pi. In fact, this coupling, called substrate level phospohorylation, is the process by which ATP is synthesized in glycolysis.

Answer 2

yes