Why do we heat the test tube in a glass beaker during a chemistry experiment and not directly over a flame?

It is not directly over a flame because it depends on the substance you might not want to heat it too much.you never know what could happen

Google it that might work

This is what i found on google “when one phosphate group is removed by breaking a phosphoanhydride bond in a process called hydrolysis, energy is released, and atp is converted to adenosine diphosphate (adp). likewise, energy is also released when a phosphate is removed from adp to form adenosine monophosphate (amp).” i hope this you .