Cassidy Espeseth - Wednesday, October 12, 2016


The purpose of this experiment was to learn more about enzymes and catalysts in biochemical reactions. One person's fingers are the enzyme: toothpickase, and the toothpicks were the substrate. We used the experiment to see how substrate concentration and other factors affect the rate of reaction.


I hypothesized that toothpickase would be quicker when the concentration of toothpicks was larger. I thought that toothpickase would work faster when the 50 toothpicks were all together on the plate. I also hypothesized that the rate of reaction would be faster when there were two toothpickases.


  • 150 toothpicks
  • Small plate
  • Timer
  • Pencil

Procedure and Data


  1. If there were 2,000 toothpicks to begin with, the reaction rate would increase as you continued through the time. There are more toothpicks to break, so toothpickase could work faster. I think with 2,000 toothpicks, toothpickase would keep breaking more and more toothpicks through the 120 second time period, but if he continued to break for a longer period of time, the rate would slow again.
  2. The reaction rate increased slightly when there were two toothpickases. We didn't see a huge increase, but because there were more toothpickases, they could break toothpicks at a faster rate.
  3. The reaction rate was also quicker when the toothpicks were spread across the table because toothpickase wasn't constantly picking up ones he had already broken. In part A, this wasted a lot of time, but toothpickase had an easier time separating products from reactants when the toothpicks were spread apart.
  4. The reaction rate would be much faster if the products had been separated from reactants. Toothpickase would not have picked up any broken toothpicks, so each time he picked a toothpick up, he would have broken it.
  5. If plastic toothpicks were added, the reaction rate would have been slower. The plastic toothpicks would be harder to break and would have slowed down toothpickase. Plastic toothpicks would represent competitive inhibitors because they would bind to the enzyme in the active site where the substrate binds.


The first hypothesis I made was rejected; the toothpickase was quicker when the concentration of toothpicks was lower. The second hypothesis I made was accepted. The reaction was faster when there were two toothpickases. Sources of error may include differences between when the timer called time and when the recorder recorded data. The toothpickase may have had difficulty keeping a constant pace. It was difficult for the toothpickase to stay turned away from the toothpicks, so some error may be due to the toothpickase seeing the toothpicks. Through this activity, I now better understand enzymes and some factors that may affect reaction rate.