same way. I did not prepare a ?batch? of solutions as this would have given
some more time to acclimatise and more time to react and respire, changing the
conditions. When weighing out glucose and yeast on the top pan balance, I
checked that the air bubble was always centered and adjusted it accordingly, if
left uncentered, this could cause biased results. When measuring out distilled
water, I carefully checked that the bottom of the water?s meniscus sat
horizontal with the required gradient on the measuring cylinder when looked at
from 90? at the side. I also kept the same water in the water bath so as to
keep fair the distribution of heat to the test tubes, I mixed this as well.To further manipulate my results I shall record logs of my results so I
can plot this in my analysis. This will also display my results in such a way
that will allow me to easily find an optimum temperature for anaerobic
respiration in yeast. It will also allow me to calculate the Q10 mean value for
my experiment. This would go some way to see the accuracy of my results, but
mostly to see whether the reaction is in line with the Q10 theory and
regularity of the rate of reaction. I will plot log temp against log rate? to generate my log graph. This is one of
many data manipulation methods I shall use in my analysis to find out as much
as I can from my data. Here are my log tables including the results taken when
plotting out the plateau:See Attatched Document
??? 20?? 1.301?????????????? ???? 2.36???
?????? 0.373????????????? ??? 30?? 1.477?????????????? ???? 3.31???
?????? 0.198 ??? 40?? 1.602?????????????? ?? ??7.41??? ?????? 0.870 ??? 42?? 1.623?????????????? ???? 8.55???
?????? 0.932 ??? 44?? 1.643?????????????? ???? 9.80???
?????? 0.991 ??? 46?? 1.663?????????????? ???? 10.4???
?????? 1.017 ??? 48?? 1.681?????????????? ???? 11.2?????????? 1.049??? ??? 50?? 1.699?????????????? ???? 11.6?????????? 1.065? ??? 52?? 1.716?????????????? ???? 12.2?????????? 1.086 ??? 54?? 1.732?????????????? ???? 10.7?????????? 1.029 ??? 56?? 1.748?????????????? ???? 10.2?????????? 1.009
See Attatched DocumentBiology Science 1 – Strand
3: Analysis Summary????????? I found that as the
temperature increased, the rate of respiration increased with it. I also found
that the rate of respiration dropped of completely after a certain point,
highlighting the denaturisation of the yeast?s enzymes.
See Attatched Document
??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
????????? ???????????????????????????????????????????? ?????????????????????????????????????????????????? This shows that
the temperature
See Attatched Document
??????????????????????????????????????????????????????????????????????????????????????????????????????????????? a certain point
where respiration ??????????????????????????????????????? ??????????????????????????????????????????????? stops.??????????????????????????????????????????????????????????????? Temp
(?C)To calculate the Q10 gradient of my results so I can gain information
about the nature of the reaction, I shall create a graph of my logs given in my
Obtaining. From my log graph I can give the optimum temperature for yeast
respiration and calculate the Q10 reading for my experiment.I can calculate my Q10 value as shown: ? See Attatched Document See Attatched Document
See Attatched Document Conclusion ??????? I have found that as I
increased the temperature of the yeast solution, the rate of respiration of the
yeast increased to a certain point where, as the temperature rose to a certain
level, (in my case about 58?C) the rate of respiration eventually cut off. I
have also found that my Q10 value is 1.43. Seeing as the most accurate value
for a Q10 reaction is 2 (the rate of reaction doubling for every 10?C rise)
this makes my reaction look a bit inaccurate yet with positive signs of
correlation. A Q10 reading as low as 1.43 suggests there were either faults
with the method or apparatus or that the reaction was not a true Q10=2
reaction; this reaction should be a typical Q10=2 reaction, so my method or
apparatus? probably give the
inaccuracies. I will talk further about this in strand iv to suggest reasons. ??????????? My hypothesis and
prediction can be backed up with the findings; from looking at my results and
graphs you can see the rise and fall of respiration, further displayed by the
reaction?s Q10 reading which, although quite a lot less than 2, it still gives
the presence of the reaction?s ?sensitivity? (through zymase) to temperature.
Thus my hypothesis and prediction are shown to be present and displayed to a
large extent. They are explained due to the theories of enzyme-substrate with
lock and key and kinetics. Where these meet is when kinetic theory states that
an increase in temperature means more particle collisions between reactants and
so a faster rate of reaction; and in enzyme-substrate where the enzyme is
sensitive to heat, and about a certain temperature, the active site will begin
denaturing, so slowing and eventually stopping the reaction. This will give an
area where the rate of respiration drops off and goes to nothing instead of a
precise ?cut-off? point. These both apply to my experiment and were described
in my planning. ??????????? Biology Science 1 – Strand 4: Evaluation My Method??????????? The experiment went
quite well as I was able to obtain sets of recordings and calculate means,
rates and logs, and my Q10 value from them.I did not find any results to be anomalous when looking at the results
table. This could be explained by the small spread of results at each interval
and that the reaction could not be totally accurately controlled with the
apparatus used.I think that the method I used, whilst giving results, was also quite
sensitive to changes and didn?t allow to tap the full potential of the
experiment. I would suggest using equipment which would not allow any biased
results or ignore anything that is happening in the solution. I would want to
spread out the solution in something like a pert dish to give maximum surface
area to help conduct heat and to evenly spread the methyl blue. I would
consider either not using the methyl blue colour change technique at all or use
a substance which is more precise as I felt that the method did not allow
accurate use of methyl blue because of how it was used and what it acted on.
This added to the slight ?unpredictability? of the experiment.My Results ??????????? ??????????? To make sure that the
results were as reliable as I could make them, I calculated the mean of three
results at each interval when dealing with the rate and also used these to
produce my log values. ??????????? I took all precautions
to make the apparatus used to be reliable and give good values so I think the
slight unreliability was caused by the preparation of the solution and the ?unpredictability?
of how the reaction went that came with it. To obtain more reliable results I
would want complete continuity with preparations, maybe arranging ?sets? of
substances to create multiple solutions beforehand or preparing them but not
actually activating the yeast so as to prevent any getting a ?head start? over
the others. This would ensure that all the preparations are the same and would
give continuity. I would want to be more strict and thorough with preparing
solutions and mixing them up. I would want each one to be thoroughly
acclimatised to the surroundings and had the same amount of methyl blue and
same activating and mixing time. This would help give more reliable results
throughout. ??????????? If I were to further
investigate this experiment and my results, I would probably want to calculate
the point where the enzymes begin to denature for respiration in yeast. I could
also examine the change in rate between the intervals to determine validity and
continuity, also running them through maybe more intricate calculations
involving log. At this stage, I shouldn?t think there is to be much more I
could do. I wouldn?t want to investigate any other variables or reactions at
this time.