Students in a college made this hypothesis: ‘reaction time will increase as the time you have been awake increases.’ The students set up an investigation to test their hypothesis. This is the method used. 1. Find 5 volunteers willing to stay awake for 24 hours. 2. Keep the volunteers in a room where they can study, use an exercise bike or watch TV as they wish. 3. Provide food, water, coffee and tea as requested. 4. Measure the volunteers’ reaction time every 4 hours using a computer program. (b) What was the independent variable in this investigation?

1. an enzyme is considered a(n) because it speeds up a chemical reaction without being used up.2. in a catalyzed reaction, a reactant is often called a(n) . an enzyme is specific because the shape of its matches only particular reactants.4. an enzyme speeds up reactions by lowering the . the between an active site and its substrate often strains bonds and the reaction proceed.6. a( , which is often a vitamin, binds to an enzyme and plays a role in catalysis.7. high temperatures or changes in ph can an enzyme, causing it to lose its shape and biological activity.