You’ve taken it a lot farther down the road than needed.
If, in violation of the Second Law of Thermodynamics, a collection of molecules were somehow to magically configure themselves into a cell of algae, and it further magically comes to life “somehow”, what causes it to then split in two and each of the two halves to then regrow to the size of the original cell and repeat that process indefinitely?
If it split in two; wouldn’t it then be HALF the size?