Calvin cycle is a biochemical process that accounts for the carbohydrate production done by the plants. It is divided in three stages fixation (enzyme RuBisCO incorporates carbon dioxide into an organic molecule), reduction, and regeneration in which Ribulose bisphosphate (RuBP), the molecule that starts the cycle, is regenerated so that the cycle can continue.
PLA is a type of condensation polymer. Hydroxyl group of one lactic acid reacts with carboxylic group of second lactic acid and a ester is formed with the elimination of water molecule. And the reaction propagates with the increase in chain. And, the product formed is PLA as shown below.