Cellular Respiration Lab
This lab works with peas in order to experiment with and document the
results of cellular
respiration. Cellular respiration is how a cell breaks
down
glucose and
oxygen to form
carbon dioxide and
water, but more
importantly, 686 kilocalories per
mole of glucose is harnessed from the
reaction. We worked with both
germinated and non-germinated peas and
documented how much oxygen was released at different amounts of time. Since
the germinated seeds are forming new life which requires
energy, they were
using more oxygen than the non-germinated seeds which did not require energy
(the more oxygen used, the more reactions are happening). By adding water
to non-germinated seeds, the seed begins the cellular respiration process
and begins to grow because it has access to the energy that is yielded from
the reaction.
In order for us to document how much oxygen was used we first had to
eliminate the carbon dioxide from the equation because otherwise the
measurements of the gas in the
pipette would not only be oxygen but carbon
dioxide also. To keep this from happening, KOH was added to the
respirometer to form two solids when carbon dioxide reacts with the KOH:
water and K2CO3. This allowed us to collect the data for how much oxygen
was being used without the interference of carbon dioxide.
The group I was in conducted the experimented at twenty degrees and our
experiment seemed consistent with what was expected: our dry beads’
corrected rate did not change throughout the time intervals which showed
that no cellular respiration occurred in the seeds. Since non-germinated
seeds are not alive, no cellular respiration should take place. For our
warm reading at thirty degrees, we used another group’s data. There are
reasons to believe that this data resulted from problems in the experiment
because the dry peas’ rate not only changed from interval to interval but
was also negative. Because the Q10 is found by using rates from both the
thirty and twenty degree trials, our Q10 is not correct either. It was
obvious, however, that heat played a role in cellular respiration because
more oxygen was used even though both trails occurred in the same time
scale.