Match the following. 1 . buffer Two or more units are added together to form a new compound 2 . enzyme Accelerates a chemical reaction without being used up in the reaction 3 . catalyst When a reversible reaction is occurring in both directions at the same rate 4 . chemical equilibrium All of the chemical reactions in the organism for maintenance of the processes of life 5 . synthesis reaction A substance which will resist changes in pH within reasonable limits 6 . metabolism A protein molecule which speeds up a specific chemical reaction in biological systems