Students conducted an experiment to check the rate of enzyme action on different types of food. the table shows the results
of an experiment in which students placed hydrogen peroxide on several food samples and recorded the relative amount of
fizz that each produced. the fizz was produced by oxygen bubbles released by the action of the enzyme catalase, which is
found in almost every living cell
the students conducted a second experiment, using the raw chicken liver from the previous experiment. they modified the
chicken liver and used: one whole piece one piece cut into two, a piece that they pulverized in a blender. all the livers were the
same mass. the liver was placed in test tubes and hydrogen peroxide was then added to
was placed in test tubes and hydrogen peroxide was then added to each. here are the results
chicken liver and enzyme action
liver condition rate of fizing
whole
two pieces 11
pulverized
14
based on the students experiments, what conclusion can be drawn?
mechanical digestion has no bearing on the chemical digestion of food.
chemical digestion in this case, enzyme activity, is aided by mechanical
di gestion
chemical digestion occurs at the same rate regardless of the condition of
the chicken liver.
the blending represents mechanical digestion and the enzyme activity
represents chemical digestion

Rease is an enzyme used by plants to break down urea (a nitrogen-containing compound) into carbon dioxide and ammonia. urease urea > > > carbon dioxide and ammonia ammonia is broken down by plants into a nitrogen source plants need to grow. thus, plants could not use urea as a nitrogen source unless it was first converted to ammonia. in soybean plants there are two different kinds of urease, one produced in the seeds and the other produced in the leaves of the plant. three types of soybean plants were used in a set of experiments: normal soybeans and two mutant strains, one lacking the urease in the seeds only (strain 1) and one lacking urease in the leaves only (strain 2). experiment 1 separate areas in a field were planted with normal, strain 1, and strain 2 soybeans. all types of soybeans appeared to grow, flower, and produce seeds equally well. there were no externally detectable differences among the strains. experiment 2 small pieces of plant leaves of equal weight were obtained from each type of soybean plant and separately placed on media in culture dishes. tissue growing in this way will become an unorganized clump of cells referred to as callus. to provide a controlled nitrogen source, half the tissue samples of each type were placed on media containing urea, and the other half of the samples were placed on media containing ammonia. after 30 days, the weight gain for each of the callus samples was determined. results are shown in the table below.