7. Energy and Metabolism

Which of the following statements is TRUE regarding an enzyme's function?

a) It is generally increased if the structure or conformation of an enzyme is altered.

b) It is independent of factors such as pH and temperature.

c) It increases the rate of chemical reactions by lowering activation energy barriers.

What is a transition state? a. the shape adopted by an enzyme that has an inhibitory molecule bound at its active site b. the amount of kinetic energy required for a reaction to proceed c. the intermediate complex formed as covalent bonds in the reactants are being broken and re-formed during a reaction d. the enzyme shape after binding an allosteric regulatory molecule

If an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur? a. Additional substrate will be formed. b. The reaction will change from endergonic to exergonic. c. The free energy of the system will change. d. Nothing; the reaction will stay at equilibrium.

If you were to expose glucose to oxygen on your lab bench, why would you not expect to see it burn as described by the reaction in Figure 8.6? a. The reaction is endergonic and requires an input of energy. b.The reaction is not spontaneous unless an enzyme is added. c. The sugar must first be phosphorylated to increase its potential energy. d. Activation energy is required for the sugar and oxygen to reach their transition state.

A biologist performed two series of experiments on lactase, the enzyme that hydrolyzes lactose to glucose and galactose. First, she made up 10% lactose solutions containing different concentrations of enzyme and measured the rate at which galactose was produced (grams of galactose per minute). Results of these experiments are shown in Table A below. In the second series of experiments (Table B), she prepared 2% enzyme solutions containing different concentrations of lactose and again measured the rate of galactose production. (b) Graph and explain the relationship between the reaction rate and the substrate concentration. How and why did the results of the two experiments differ?.

A biologist performed two series of experiments on lactase, the enzyme that hydrolyzes lactose to glucose and galactose. First, she made up 10% lactose solutions containing different concentrations of enzyme and measured the rate at which galactose was produced (grams of galactose per minute). Results of these experiments are shown in Table A below. In the second series of experiments (Table B), she prepared 2% enzyme solutions containing different concentrations of lactose and again measured the rate of galactose production. (a)Graph and explain the relationship between the reaction rate and the enzyme concentration.