Answers  to questions 1-5 page 271 1.Manganese dioxide speeds up the decomposition of hydrogen peroxide.    Chlorine atoms speeds up decomposition of ozone gas in the atmosphere.    Amylase is an enzyme that speeds up the breakdown of starch in the foods we eat during the process of digestion.   Peroxidase is an enzyme in the liver that speeds up the decomposition of hydrogen peroxide.   2. a) Enzymes are biological catalysts - they speed up the synthesis and breakdown of chemicals in biological systems.  Enzymes are only one type of catalysts. b) Amylase is an enzyme that speeds up the breakdown of starch in food during digestion; peroxidase is an enzyme in the liver that speeds up the decomposition of hydrogen peroxide.   3. Many enzymes are heat sensitive: they break down at higher temperatures.  Therefore, as the temperature is increasing, there are fewer enzymes available to control the chemical reactions in the body.  For example, cooking pineapple "dentatures' the enzymes that digest protein, make it nonfuntional. 4. a) Chlorine catalyze in CFCs catalyze the decompositon of ozone in the stratoshpere.   b) It takes many years for these chemicals to travel from their point of release on the ground up into the stratosphere.  CFCs are still used in some countries.  Also, they persist for years in the atmosphere, and since they are a catalyst, they aren't consumed in the reaction.  Therefore, they can keep catalyzing reactions for years.   5. a) The enzymes in the laundry detergent break down stains in the clothing that are biological in origin           ex: Food stains b) Soaking the garment in cold water gives the enzymes in the detergent time to work and decompose the stain.  Hot water would likely inhibit the action of the enzymes by breaking them down before they could effectively a