This lab is adapted from the canned denatured pineapple experiment. Instead of investigating the effect of canning on enzyme activity, we look for the presence of the substrate.
This is a useful teaching lab for all the criteria and requires very few resources.
Gelatin is made from a protein called collagen which comes from the joints of animals. Gelatin may be dissolved in hot water. As the dissolved gelatin mixture cools, the collagen forms into a matrix that traps water; as a result, the mixture turns into the jiggling semi-solid mass that is jelly. Pineapple belongs to a group of plants called Bromeliads (also includes kiwi, papaya & figs). The enzyme in pineapple juice that is responsible for the breakdown of collagen is bromelin.
The formal design can be decided between the teacher and students. The aim is to investigate the action of bromelin on collagen in the two jellies. Jello has collagen and KoolAid doesn’t. The students are not told this and will hopefully postulate this as an explanation for their results. This experiment works well because the students have to decide how they will collect qualitative and quantitative data. It demonstrates the importance of replication with highly variable data. We found that 30mins was long enough to see a difference.
Pineapple (blended) = enzyme
Data Collection and Processing
If each student has an n of five for each group, the data can be pooled at the end. The data was highly variable (good for evaluation), by looking at the spread of the pooled data, students can make a decision as to the validity of statistical analysis in this case.
Conclusion and Evaluation
Students will hopefully see that the pineapple had an effect on one of jellies and not the other. If all conditions, bar the substrate were consistent, they will hopefully start to think about collagen in the substrate....
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