Metabolic reactions can be shown outside the body in cell free systems experimentally. Why are cells required in living organisms?
Metabolic reactions can be demonstrated outside the body in cell-free systems. When an isolated metabolic reaction(s) is performed outside the body of an organism, in a test tube it is neither living or non-living. Hence, while metabolism is a defining feature of all living organisms without exception, isolated metabolic reactions in vitro are not living things but are living reactions. Here, it can also be said that cellular organisation of the body is the defining feature of life forms.