TEST TUBE RESPIRATION - DOC - DOC by hcj

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									                              TEST TUBE RESPIRATION
                                       Lab Report
        The alcohol fermentation pathway in yeast demonstrates cellular respiration
                           Name:      Date: 1/01/07    Class:

I. Define cellular respiration and explain how glucose gets broken down in a cell:
Respiration is the process by which cells break down simple food molecules to release the energy they contain.
It takes many steps for the glucose to be broken down. First, you eat food such as veggies, fruits, and grains.
Then, the glucose goes to the stomach and intestines where food is broken down into simple molecules/
compounds. Then, the compounds are absorbed into the blood stream through osmosis and diffusion. After, the
glucose travels into the cell through osmosis. Oxygen also enters the cell, but enters through diffusion. In the
cytoplasm, glucose gets broken down in to smaller molecules. Then, small molecules of glucose enter the
mitochondria with oxygen. After, a chemical reaction takes place between oxygen and glucose. Lastly, the
glucose breaks down even further and releases a large amount of energy.




II. Write a question about respiration that you can answer with an experiment:

If I increase the amount of sucrose or yeast in the water, then there will there be an increase in CO2 production?

III. Literature Review:

Becky Ann Bartlett carried out two separate experiments to demonstrate this idea of test tube respiration. In her
first experiment, she kept the amount of yeast the same in each test tube and changed the amount of sucrose. In
her second experiment she kept the sucrose constant and changed the amount of yeast in each tube. Both of her
experiments showed that an increase in sucrose or yeast resulted in an increase in CO2 production. The
resulting equation was as follows:

C12H22O11 + H2O + yeast              4CH3Ch2OH + 4CO2

sucrose + water + yeast               ethyl alcohol + carbon dioxide
IV. Statement of Purpose and Hypothesis:

The purpose of this experiment is to determine the amount of sucrose we feed yeast affects the amount of
respiration which takes place.

Hypothesis: If I increase the amount of sucrose that is being added to the yeast and warm water, then there
will be an increase in CO2 production.

V. Methodology:
1. Asked a question about a problem I wanted to investigate
2. Did some research on the topic and wrote a literature review
3. Developed a hypothesis
4. Designed an experiment to test my hypothesis
5. Gathered all necessary materials
6. Set up the materials as in the diagram
7. Drew and labeled a diagram of the experiment
8. Created a data collection table with the independent and dependent variables
9. Used the narrow masking tape and Sharpie to make a quick label for each tube putting numbers 1, 2,3,4,5 on
each tube
10. Filled each test tube with 10 ml of warm water using the large graduated cylinder, keeping the level the
same in each tube
11. Measured out the proper amount of sucrose for each tube using the wooden splint going up a level in each
tube, leaving one test tube with no sucrose
12. Placed my thumb over each tube and gently shook to dissolve the sucrose
13. Measured out 2ml of yeast using the small graduated cylinder for each tube and poured it into each tube
with a funnel
14. Gently shook each tube right after pouring yeast to stir contents with my thumb over the top of the tube
15. Began timer for fifteen minutes
16. Recorded observations every 5 minutes to include height of CO2 bubbles in cm

VI. Analysis of Data:

My data shows that the tube with 0 amount of sucrose measured 1 cm of CO2 bubbles. Tube 1 measured 5 cm.
Tube 2 measured 8.4 cm. Tube 3 measured 11 cm. Tube 4 measured 12 cm.

VII. Questions to answer:

Why did you have one tube without any sucrose?

We had no tube without any sucrose to see if there could be a production of CO2 bubbles with only yeast added
to the water.

What caused the yeast to start producing CO2 bubbles?

The sucrose was the main reason the yeast started producing CO2 bubbles. First, the sucrose entered the yeast’s
cells through osmosis. Oxygen is also entering the cell only by diffusion. In the cytoplasm, the sucrose that is
now glucose then gets broken down into smaller molecules. A small amount of energy is also released here.
Then, small molecules of glucose enter the mitochondria with oxygen. A chemical reaction then takes place
between the oxygen and the glucose. The glucose then gets broken down even further and here releases a large
amount of energy. The waste of this respiration then creates CO2 bubbles. They are released and that is what we
see in our test tubes.

Why was it important to have the same amount of water in each test tube?

It is important to have the same amount of water in each test tube because the experiment would not be accurate
if you didn’t. If the water wasn’t at the same level then it might affect how the yeast reacts to the sucrose. It
would then affect the efficiency of the data.

How is yeast like you?

Yeast is like me because we both need glucose to produce energy. When the sucrose got mixed together with
the yeast a chemical reaction took place. As the sucrose that became changed into glucose entered the cell it
produced energy. This happens exactly the same as it does with us. We eat fruits and veggies which is our form
of glucose and then the glucose enters the cell. As the glucose goes through respiration it produces energy for
us. We both need glucose to produce energy. Also, the more glucose we take into us or the yeast the more
energy is produced. This is the same for both of us.

VIII. Summary and Conclusion:

From my experiment I can conclude that the more sucrose that was added to the yeast, the more CO2 bubbles
they produced. My evidence is that the tube with 4 amount of sucrose measured 11cm greater than the tube with
0 amount of sucrose in the CO2 production.

Therefore, I accept my hypothesis because in my hypothesis I stated that if I increase the amount of sucrose that
is being added to the yeast and warm water, then there will be an increase in CO2 production. I can accept this
as my hypothesis because my data shows that the tube with 4 amount of sucrose measured 11cm greater than
the tube with 0 amount of sucrose in the CO2 production.

               My Data        Team Data
Tube 0         .5 cm          1 cm
Tube 1         2 cm           5 cm
Tube 3         9 cm           8.4 cm
Tube 4         10 cm          11 cm
Tube 5         12 cm          12 cm

IX. Identify the independent and dependent variables.

The independent variable in this experiment was the amount of sucrose. An independent variable is the one
factor that a scientist changes to test a hypothesis during an experiment. The amount of sucrose was the
independent variable in this experiment because we changed the amount of sucrose in each test tube. The
dependent variables were the amount of yeast added in each test tube, the amount of water added in each test
tube, and the temperature of the water in each test tube. These were all the dependent variables because each of
these variables did not change throughout the experiment. Each test tube contained 10ml of warm water, and 10
ml of yeast. They also contained a level of 1, 2, 3 or four of sucrose measured on the wooden splint. (Note: the
dependent variable in this experiment was the height of the CO2 bubbles. It changed as a result of the
sucrose being added)

								
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