Abstract:
In this lab, we
observed cellular respiration; we measured the amount of carbon dioxide
produced from various carbohydrates when in contact with yeast. We used several
different types of carbohydrates such as potato starch, honey, glucose, and
cane sugar. We used five test tubes, one
of which was the control. Every test tube including the control contained 35
milliliters of lukewarm water, 1 gram of yeast, l gram of sugar, and 0.2 grams
of salt. In each of the four test tubes we added different carbohydrates. The
control was left untouched. We placed a rubber cork with a tube attached to a
syringe (placed at l milliliter) in order to measure the amount of carbon
dioxide produced. After shaking each tube to mix the contents thoroughly, we
placed the tubes into a Styrofoam tube holder to control the temperature and
labeled them according to their starch.
We then placed the corks on top and checked the syringe every minute for
around 20 minutes to measure the amount of carbon dioxide produced.
Question:
Will different types of
carbohydrates yield different amounts of carbon dioxide during cellular
respiration?
Background:
The chemical formula
for cellular respiration is: C6H12O6 + O2 → CO2
+ H2O
+ Energy (ATP). Cellular respiration occurs in the cytoplasm and mitochondria.
Cellular respiration is a metabolic process by which food molecules are
converted into energy. This process uses carbohydrates, fats, and proteins. But
glucose is most commonly used. Cellular respiration consists of three
processes: glycolysis, Krebs cycle, and oxidative phosphorylation. Glycolysis
occurs in the cytosol, the 6-carbon sugar breaks into 2 molecules of 3-carbon
molecules called pyruvate. This process produces 2 ATP and 2 NADH molecules. In
the Krebs cycle occurs in the mitochondrial matrix and produces chemical energy
(ATP, NADH, and FADH2) from oxidation of the pyruvates from
glycolysis. In oxidative phosphorylation, the electron transport chain produces
chemical energy stored in the NADH and FADH2. There are 3 ATP
produced per NADH and 2 ATP per FADH2.
Hypothesis:
If glucose or cane sugar is placed in a container with water, yeast,
salt, and sugar, it should release more carbon dioxide than the control . Also, we expect the potato starch to
produce some carbon dioxide but not as much as the glucose or cane sugar but
more than the control. Additionally, the honey should produce the least amount
of carbon dioxide since it contains less glucose than the plain glucose but
produce more than the control.
Materials:
·
5 test
tubes
·
5
rubber corks with tubes
·
5
syringes
·
2
Styrofoam tube holders
·
water
·
yeast
·
sugar
·
salt
·
potato
starch
·
glucose
·
cane
sugar
·
honey
·
labels
·
graduated
cylinder
Procedure:
1. Put 35 milliliters of water, 1 gram of yeast,
1 gram of sugar, and 0.2 grams of salt in each 5 test tubes
2. Add 0.2 grams of glucose, potato starch, honey,
and cane sugar in different test tubes
3. Label each tube according to the different
starch
4. Do not add any carbohydrate to the fifth test
tube so that it can be the control
5. Have your lab partner help you shake the
tubes thoroughly so that nothing sticks to the bottom
6. Then very quickly place the corks with the
tubes and syringes(placed at 1 milliliter) on each of the test tubes
7. Then place the tubes into the Styrofoam tube
holders
8. Then check the syringes every minute for 20
minutes and record your data, make sure that the corks are tightly placed on
each of the tubes, they may loosen
Results:
Milliliters of Carbon Dioxide vs. Number of
Minutes
the y-axis is in milliliters
the x-axis is in minutes
|
Add
on Starches
|
1
minute
|
2
minutes
|
3
minutes
|
|
Potato
Starch
|
1
ml
|
1ml
|
1ml
|
|
Glucose
|
1ml
|
1ml
|
1
ml
|
|
Honey
|
1ml
|
1ml
|
1ml
|
|
Cane
Sugar
|
1ml
|
1ml
|
1ml
|
|
Control
|
1ml
|
1ml
|
1ml
|
|
|
4
minutes
|
5
minutes
|
6
minutes
|
|
Potato
Starch
|
1
ml
|
1ml
|
1ml
|
|
Glucose
|
1ml
|
1ml
|
1
ml
|
|
Honey
|
1ml
|
1ml
|
1ml
|
|
Cane
Sugar
|
1ml
|
1ml
|
1ml
|
|
Control
|
1ml
|
1ml
|
1ml
|
|
|
7
minutes
|
8
minutes
|
9
minutes
|
|
Potato
Starch
|
1
ml
|
1ml
|
1ml
|
|
Glucose
|
1ml
|
1ml
|
1
ml
|
|
Honey
|
1.01ml
|
1.01ml
|
1.05ml
|
|
Cane
Sugar
|
1ml
|
1ml
|
1ml
|
|
Control
|
1ml
|
1ml
|
1ml
|
|
|
10
minutes
|
11
minutes
|
12
minutes
|
|
Potato
Starch
|
1
ml
|
1ml
|
1ml
|
|
Glucose
|
1.02
ml
|
1.02
ml
|
1.02
ml
|
|
Honey
|
1ml
|
1ml
|
1ml
|
|
Cane
Sugar
|
1.05
ml
|
1.05
ml
|
1.05
ml
|
|
Control
|
1ml
|
1ml
|
1ml
|
|
|
13
minutes
|
14
minutes
|
15
minutes
|
|
Potato
Starch
|
1
ml
|
1.20ml
|
1.90
ml
|
|
Glucose
|
1.02
ml
|
1.40
ml
|
1.80
ml
|
|
Honey
|
1ml
|
1ml
|
1ml
|
|
Cane
Sugar
|
1.05
ml
|
1.30
ml
|
2
ml
|
|
Control
|
1ml
|
1ml
|
1ml
|
|
|
16
minutes
|
17
minutes
|
|
|
Potato
Starch
|
1.60
ml
|
1.60
ml
|
|
|
Glucose
|
2
ml
|
2
ml
|
|
|
Honey
|
1ml
|
1ml
|
|
|
Cane
Sugar
|
2
ml
|
2
ml
|
|
|
Control
|
1ml
|
1ml
|
|
Conclusion:
In this lab, we found that glucose and cane sugar had generated the most
carbon dioxide which fails to reject our hypothesis and produced 1 milliliter
more carbon dioxide than the control (35 milliliters of water, 1 gram of yeast,
1 gram of sugar, and 0.2 grams of salt). Our hypothesis of the potato starch
producing less than glucose and cane sugar but more than the control is also
true. The potato starch produced 0.6 milliliters more carbon dioxide than the
control. Our hypothesis about the honey was partially rejected, it produced
less carbon dioxide than the glucose and the cane sugar as we expected, but the
honey did not produce more carbon dioxide than the control. The honey and the
control did not produce any carbon dioxide, and the glucose and cane sugar
produced the most carbon dioxide. Even though the control and honey
also contained sugar it did not produce carbon dioxide. The two constants in
this lab are temperature (from placing the tubes in the Styrofoam tube holders)
, and the 35 milliliters of water, 1 gram of yeast, 1 gram of sugar, and 0.2
grams of salt in each test tube. Another constant is also the duration of time
for cellular respiration to occur and be measured. Two potential sources of
error are not adding equal amounts of the different carbohydrates to each of
the different test tubes, and not placing the corks properly on each of the
test tubes. If the tubes are not placed properly then carbon dioxide can escape
and not be measured in the syringe. Our
data is not completely accurate, we did not properly read the syringes
throughout the lab so that may have been the cause , also there could have been
a leak in a couple of the tubes which might explain why the potato starch 's
level of carbon dioxide decreased near the end of the lab and why the honey and
control did not produce carbon dioxide.This lab proves that glucose is a major
source of energy and produces more energy faster than other carbohydrates.
Citations:
Pearson.
"Cell Respiration: Overview of Respiration." Cell Respiration:
Overview of Respiration. N.p., n.d. Web. 15 Feb. 2014.
