Yeast Balls

Yeast lab results

This week we basically just focused on the yeast ball lab and how quickly the yeast was catalyzed. So here’s what happened:

Catalase which is found in both plant and animal cells has a very important function in which it prevents the accumulation of toxic levels of H2O2 (a by-product of metabolic processes). An example of this is shown in the yeast lab. Our lab group first made yeast balls by dropping in little amounts of yeast cells to sodium alginate (a non-toxic, algal-extract) to form uniform spheres. After harnessing the spheres, we dropped them in a H2O2 solution (beware! don’t get H2O2 on clothes or it will bleach it) and timed how fast they rose to the surface after touching the bottom. This time will tell us about how fast the rate of reaction is in which yeast breaks down H2O2 into H2O and O2. The yeast particles bind with the newly released oxygen, and the oxygen pulls the yeast balls upward with it.

After creating the control, our lab group experimented with increasing and decreasing the temperature of the H2O2. First, we heated it to about 55 C. And what we found was that it took about 7 less seconds for the yeast balls to rise! Pretty cool stuff. After, we cooled the H2O2 down to 10 C, which made the time increase about 6 more seconds than the control.

Both of these experiments proved that the temperature of where the catalysis takes place effects the the rate of reaction. The higher the temp, the faster the rate of reaction and vice versa. With higher temperatures, there are far more energy high collisions which allow the substrate to be catalyzed more quickly. [ 4.B.1] What would have been interesting to test is how high/cold the temperature has to be for the yeast balls to be unable to catalyze the H2O2, or in other words denature.

A few questions I have:

Is the faster rate of reaction better? Is there ever a time in which our bodies need slower rates of reaction?

If higher rates of reaction/catalysis is more useful to our bodies, why can’t out internal temperatures increase to meet that need?


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