Unformatted text preview: osphate (ATP) H 2O
Adenosine diphosphate (ADP) + How ATP Performs Work • The three types of cellular work (mechanical, transport, and chemical) are powered by the hydrolysis of ATP • In the cell, the energy from the exergonic reacEon of ATP hydrolysis can be used to drive an endergonic reacEon • Overall, the coupled reacEons are exergonic • ATP drives endergonic reacEons by phosphorylaEon, transferring a phosphate group to some other molecule, such as a reactant • The recipient molecule is now phosphorylated Fig. 8-10
NH3 NH2 Glu Glu ∆G = +3.4 kcal/mol Glutamic acid Ammonia Glutamine (a) Endergonic reaction 1 ATP phosphorylates glutamic acid, making the amino acid less stable. P
Glu + ATP Glu + ADP NH2 2 Ammonia displaces the phosphate group, forming glutamine. P
Glu + NH3 Glu + Pi (b) Coupled with ATP hydrolysis, an exergonic reaction FAVORABLE REACTION b...
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