How iBacalao reviews an Internal Assessment draft

Synthetic smoke-test input

The same fixture used to exercise the review route

This text is invented for testing. It is not student work and contains deliberate weaknesses so the review pipeline has criterion evidence and revision issues to identify.

This internal assessment investigates how changing the concentration of hydrogen
peroxide affects the rate of the catalase enzyme reaction in potato tissue. The
research question is: how does the concentration of hydrogen peroxide affect the
volume of oxygen produced by catalase in potato discs over sixty seconds? I chose
this topic because enzymes are important in biology and I wanted to understand
how substrate concentration changes reaction rates in a measurable way.

For the method, I cut potato discs using a cork borer so that each disc had the
same diameter. I placed three discs into a conical flask containing hydrogen
peroxide at concentrations of one, two, three, four and five percent. I collected
the oxygen produced using a gas syringe and recorded the volume after sixty
seconds. I repeated each concentration three times and calculated a mean value.
The temperature of the room was not controlled, and I did not measure the pH of
the solutions. The potato came from the same potato for all trials.

My results showed that as the concentration of hydrogen peroxide increased, the
volume of oxygen collected also increased. At one percent the mean volume was
twelve millilitres and at five percent the mean volume was forty eight
millilitres. The relationship looked roughly linear across the range I tested,
although the increase between four and five percent was smaller than the earlier
increases, which might suggest the enzyme was approaching saturation.

In conclusion, higher substrate concentration increased the reaction rate. The
experiment could be improved by controlling temperature with a water bath and by
using more repeats to reduce the effect of random error.