Factors affecting enzyme action: STAGE OF LIFE- developmental years, seasonal growth periods, damage to an organism after repair of tissue, AVAILABILTY OF NUTRIENTS AND ENERGY- substances are required to build new organelles, processed in slowed when nutrients are not available, LOCATION OF CELLS- specific areas within the organism require varying rates of growth or replacement, ENVIRONMENTAL FACTORS- influenced by enzymes e.g temperatures, PH, salt, toxicity, high levels of ions denature enzymes