Question

for following group of questions first study the description of the data and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. to study the actions of the enzyme catalase on hydrogen peroxide, students performed the following experiment. catalase was extracted from potatoes by blending raw potatoes in a blender with cold distilled water. the filtrate was stored on ice. the following hydrogen peroxide solutions were made: 1 percent, 5 percent, 10 percent, and 15 percent. filter paper disks were soaked in the catalase filtrate and dropped into beakers containing the various solutions. the activity of the enzyme was measured by the amount of time it took for the disks to float to the surface of the solution on the bubbles produced by the reaction. the following data were obtained: hydrogen peroxide solution, average time, in seconds, for disks to float: 1%, 30 sec; 5%, 25 sec; 10%, 20 sec; 15%, 10 sec which of the following best explains why the disks rose to the surface faster in the more concentrated hydrogen peroxide solutions? a there was more enzyme present in the more concentrated solutions. b a greater amount of heat was generated in the more concentrated solutions. c the more concentrated solutions lowered the activation energy of the reaction. d the higher substrate concentrations in the more concentrated solutions speeded the reaction. e the density of the water was lower in the more concentrated solutions.

Explanation:

Enzymes like catalase act on substrates (hydrogen peroxide here). Higher substrate concentration (more concentrated hydrogen peroxide solutions) leads to more frequent collisions between the enzyme and substrate, speeding up the reaction and causing the disks to rise faster. The amount of enzyme remains the same across all solutions, heat generation is not the main factor here, the enzyme lowers activation energy but the concentration of substrate affects reaction rate, and water density is not relevant to the reaction - rate increase.

Answer:

D. The higher substrate concentrations in the more concentrated solutions speeded the reaction.