bioNRICH is the area of the stemNRICH site devoted to the
mathematics underlying the study of the biological sciences,
designed to help develop the mathematics required to get the most
from your study of biology at A-level and university.
Stage: 5 Challenge Level:
This question contains a lot of 'unused' information, so try to be
clear as to which parts enter the calculation.
You might want to think through the problem in these steps:
First consider how the molar extinction coefficient relates to the
absorbance of the initial solution in the light path cuvette using
the Beer-Lambert law.
Then work out how a change in this absorbance relates to a change
in the concentration. From this you can work out the change in the
number of moles of chemical due to the sample of extract added to
Then you can scale up to determine the number of katals present in
the original extract.
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the
NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to
embed rich mathematical tasks into everyday classroom practice. More information on many of our other activities
can be found here.