Final answer:
Living cells require constant input of free energy to maintain organization, as supported by empirical data and the laws of thermodynamics.
Step-by-step explanation:
The hypothesis based on the two laws of thermodynamics that determines if something is a living cell or not is that all living systems require constant input of free energy to maintain organization, grow, and reproduce. This hypothesis is supported by empirical data that shows that living things are highly ordered and require energy input to maintain a state of low entropy.
Living systems take in energy-storing molecules and transform them through chemical reactions, but no reaction is completely efficient, resulting in the loss of usable energy. Additionally, living systems produce waste and by-products that are not useful energy sources, increasing the entropy of the system's surroundings.
As per the second law of thermodynamics, every energy transfer or transformation increases the entropy of the universe. While living things maintain a state of low entropy, the entropy of the universe in total is constantly increasing due to the loss of usable energy with each energy transfer. Therefore, the constant need for energy input to maintain organization is a defining characteristic of a living cell.