Question

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
5%	25 sec
10%	20 sec
15%	10 sec

which of the following best describes why the disks rose to the surface faster in the more concentrated hydrogen peroxide solutions?
the density of the water was lower in the more concentrated solutions.
there was more enzyme present in the more concentrated solutions.
a greater amount of heat was generated in the more concentrated solutions.
the higher substrate concentrations in the more concentrated solutions speeded the reaction.
clear my selection

Explanation:

Enzymes like catalase act on substrates (hydrogen - peroxide here). Higher substrate (hydrogen - peroxide) concentrations in more concentrated solutions increase the frequency of enzyme - substrate collisions, speeding up the reaction and causing more bubbles to form faster, which makes the disks rise faster. The density of water isn't the key factor, the amount of enzyme is kept constant in the experiment, and heat generation isn't the main reason for the faster rise.

Answer:

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