Internal Energy Change in Thermodynamics

A system is undergoing a thermodynamic process where a quantity of heat (Q) is added to the system, and the work (W) done by the system on the surroundings is recorded. According to the first law of thermodynamics, the change in internal energy (ΔU) of the system can be expressed as:

ΔU = Q - W

Given that 500 J of heat is added to the system and the system does 200 J of work on the surroundings, what is the change in internal energy of the system?

Which of the following concepts directly relates to this calculation in understanding the limitations of energy exchanges within biological systems?