Note: Modifier 59 should not be appended to an E/M service. modifier 25. Service.â These modifiers are XE, XS, XP, and XU, and collectively they are referred to as -X{EPSU}. The -X{EPSU} modifiers are more selective versions of the -59 modifier. Ipsilateral On the same side; affecting the same side of the body; the opposite of contralateral. brain or spinal cord lesions producing them.
KEY ENERGY PROCESSES IN CELLS. Most of what a cell does involves endergonic reactions, requiring constant energy input; these reactions are coupled to just a few exergonic reactions which supply that energy. The key fuel source in cell reactions is Adenosine Triphosphate, or ATP. The molecule is an amino acid linked to a ribose sugar, linked to a string of three phosphate groups (there are also ADP, Adenosine Diphosphate, and AMP, Adenosine Monophosphate).
Answers. Best Answer: ATP is the primary source of free energy in all living cells. ATP provides the energy for muscles to contract, nerves to conduct impulses, and all that cells require to build protein, pump in substances they need, permit enzymes to act, and so on.