Phosphorylation of adp to atp is endergonic, whereas the hydrolysis of atp to adp is exergonic. the two reactions are therefore said to be

The phosphorylation of ADP to ATP and the hydrolysis of ADP to ADP are said to be COUPLED reactions. This is because phosphorylation of ADP to ATP is endergonic, whereas the hydrolysis of ATP to ADP is exergonic. In a coupled reaction, the energy that one process requires is supplied by another process.

straight probes are used primarily for measuring flow as it is approaching the test area. its geometry allows the probe to be mounted so that it is in the direct line of airflow.