| MadSci Network: Biochemistry |
Hello Faeza,
This is the first I’ve heard of an experiment to test the effect of silver
nitrate on catalase activity. The first thing I want to recommend to you is
to read the MadSci FAQ on catalase:
http://www.madsci.org/FAQs/catalase.html
To see how different concentrations of silver nitrate alter the rate of
reaction of catalase on hydrogen peroxide, a simple experiment could
involve roughly measuring the amount of gas evolved over a specified short
time period (say, one minute), from a test tube in which a constant amount
of enzyme is fed with a constant amount of hydrogen peroxide, with the
amount of silver nitrate being varied. You can quantify the amount of gas
evolved by connecting your tube to an inverted beaker or burette, where the
evolved gas would displace a liquid, whose volume you could measure (see,
for example,
http://itl.chem.ufl.edu/2041_f97/lectures/lec_a.html).
That same website also shows how you can make a makeshift manometer to quantify
the gas produced by the reaction (I would use the open tube configuration
for safety). If you just want to be approximate, you could have the gas go
into a balloon and you could measure the circumference of the balloon as it
fills.
If you are going to do this experiment, I would run some control
experiments too, for example, in addition to silver nitrate, you could try
some other salts like sodium chloride, sodium nitrate, etc. I wonder if
silver nitrate would have a smaller, larger, or equal effect compared with
other salts. It’s not quite “fair” to just compare silver nitrate to no
silver nitrate, since there may be nothing “special” about that particular
salt other than its contribution to the ionic strength of the liquid, when
it is dissolved.
Finally, I would run several repeats (scientists call these “replicates”)
of each of your experimental conditions to get some confidence that your
measured results are real and not just occurring by random chance.
Scientists analyze their data, ideally full of replicates, using
statistics, which enable us to answer questions like, “Is A really
different from B?”
Good luck and have fun!
-Alex Tobias
Try the links in the MadSci Library for more information on Biochemistry.