what does it mean

"isolated metabolic reactions in vitro are not living things but surely living reactions ."

All living organisms are made up of chemicals. These chemicals can change into different biomolecules through various chemical reactions. The sum total of all chemical reactions occurring in the body of living organisms is known as metabolism. So, all the living organisms whether unicellular or multicellular exhibit metabolism. However, metabolic reactions can also be carried out outside the body in a cell free system. So, the metabolic reactions are living reactions since they are the characteristic feature of living organisms but isolated metabolic reactions carrying out in vitro represent the non-living things.