Atoms and molecules and the structures they build depend intimately on the properties of their particulate constituents. The sun shines because of the physics and chemistry of hydrogen and helium, which depend on the properties of protons, neutrons, electrons, neutrinos, and photons. Cells do what cells do mostly because of the physics and chemistry of the molecular constituents, which again depend on the properties of the fundamental particles. If you change the masses of the fundamental particles you change how they behave, and so you change more or less everything.
