Cell Respiration Bean Lab

Cellular Respiration Lab - The Bean Lab
lntroduction
In today's lab, you will be investigating cellular respiration. Cellular respiration as you
know is the process that cells use to use to obtain energy from organic molecules.
Typically, you will see the equation for cellular respiration represented in the equation
below.
CeHrzOo + 6 Oz+ 5CO2 + SHzO + EnergY
This equation represents aerobic cellular respiration. Aerobic respiration occurs in the
mitochondria of eukaryotic cells and only in the presence of oxygen. Aerobic cellular
respiration is a very efficient process which yields up to 38 molecules of ATP for each
molecule of giucose.
Aerobic cellular respiration is not the only form of cellular respiration that occurs in
living things. Cellular respiration also occurs if no oxygen is present in a process known
as anaerobic respiration. Anaerobic respiration is much less efficient at converting
glucose into ATP, yielding only 2 molecules of ATP for each molecule of glucose.
Additionally anaerobic respiration produces lactic acid or ethanol as products.
Today, you will be studying aerobic cellular respiration in soy beans. As a measure of
cellular respiration, you will be looking at the oxygen consumption ofthe beans. lf the
beans are carrying out aerobic respiration, they will be using oxygen. To measure
oxygen consumption, you will be constructing a device called a respirometer. The
respirometer will be submerged in water and as the beans use oxygen, water will enter
the respirometer. By measuring the volume of water that enters the repirometer, we
can determine the amount of oxygen being used by the beans.
You will be using three respirometers today. One will contain germinated soy beans,
one will contain ungerminated soy beans with a small amount of gravel, and the last
respirometer will contain only gravel. The soy beans that are germinated have been
soaked in water which starts their growth process. These beans should be actively using
energy to support this growth. The ungerminated beans are dormant and as a result,
they are not growing. tt is important that all of the test tubes contain an equal volume
of material. Since the germinated seeds are swollen with water, they occupy more
space than the un8erminated seeds. To make up the difference, gravel is added to the
test tube.

Name per _ Date
Cellular Respiration Lab Pre-lab
Read the introduction and the lab procedures before answering the questions below.
1. What is cellular respiration?
2. What are two types of cellular respiration?
b.
3. What are the differences between both types of cellular respiration?
4. What is the equation for cellular respiration?
5. What type of cellular respiration does the equation above represent?
6. How much ATP does the process above release?
7. What organism will be used in today's lab?
8. What isthe difference between a germinated seed and an ungerminated seed?
9. How will you measure the amount of cellular respiration that occurs in the lab today?
10. You will set up three respirometers today. Below describe what will be in each.
o.
11. lf orygen is consumed in the experiment, how will you know?

12. Describe how you will set up a respirometer.
13. Oxygen is taken up in this experiment, and carbon dioxide gas is given off in equal
amounts. In order to be able to observe how much oxygen is being used by the seeds,
the carbon dioxide must removed from the resoirometer. Describe how this will be
accomolished.
14. What is the purpose of the gravel in the test tube with the ungerminated soy beans?
15. How do you correct for atmospheric pressure or the effect of temperature changes
during the experiment?
16. Which of the three test tubes do vou think will have the most cellular respiration?
Explain why you think so.
17. Write out a predictive hypothesis for this experiment in correct form.

Nome
Dote
AEROBTC CELLULAR RESPTRATTON (BEAN LAB)
fn this experiment, you will compore the oxygen consumption of
nongerminoting soybeons ond genminoting soybeons.
Oxygengos is consumed during oerobic cellulor respirotion ond corbon
dioxide gas is given oIf. The uptoke of oxygen is the evidence thot on
orgonism is corrying on oerobic cellulor respirotion. Your doto will not be
affected by the releose of corbon dioxide becquse you will use potossium
hydroxide (KOH) to remove it. Note the following eguotions fon:
the removol of COz6Y KOH is' 6Q, + ?KOH ---------2 KzCOt + HzO
oerobic cellulor respirotion ist C5HpO5+ Oz (Q2 + ll2O + ATP
EXPERIMENTAL PROCEDURE
-_2
1 - Prepore o room temperoture woter both:
Fiff o green tub to q level of -5 centimeters of woter.
Attoch mosking tGPe ocross the woter both, moking q "sling" to hold the
respirometer pipette ends out of the water (see Figure b)'
2 - Construct three respirom elers (see Figure o):
Obtain three test tubes, eoch with o stoPPer ond calibroted pipette'
Lobel the tubes 1, 2, ond 3 with the greose pencil in your desk drawer'
3 - Follow all the remoining directions CAREFULLy!
place oneof the six smoll wods of obsorbenf cotton in the bottom of each
test tube.
Carefully dispense drops of 15%KOH (potossium hydnoxide) to saturote the
cotton in the tubes (fully wet, but not so99y). Do not get ony KOH on the
sides of the test tubes; the tube 4gg! be dry. Reploce o tube with o
clean one if you occidentolly get the sides wet.
ploce o smoll wod of dry cotton on top of eoch of the KoH-sooked cotton
wads. Use the some qmounts of cotton ond KoH for eoch respirometer.
4 - Obtoin o 100 ml groduoted cylinder ond odd 50 ml of woter'
Drop in twenty germinoted soybeons ond meosure the omount of woter
disploced (thot is, how much the woter rises qbove the 50 ml mork)'
Record this number here: ml.
Remove the woter ond germinoting beons.
Gently dry the beons on o Poper towel.
5 - Plqce the germinoting beons in tube 1.
fnsert the stoPper fitted with o colibroted pipette (seeFigure a)'

tube 1
germinatrng
bears,
no gravel
Figure a
tube 2
nongermlna ting
bears & gravel
tube 3
aqua.riu.Er
gravel
d.I-t cotton
KOH soaked
cotton
Figure b
. Respiromeiers in the !'/ater bath'
Beon lab P.2
masking
lape sllng
6 - Again, add 50 ml of woter to the 100 ml groduoted cylinder. This time,
drop in tweniy nongerminoting soybeons.
Add oguorium grovel until the some omount of woter is disploced os in step 4.
Dry the gravel ond beans on o paper towel.
7 - Place the nongerminoting beons and the grovel in tube Z.
fnsert the stopper fitted with o colibrated pipette.
8 - Once more, odd 50 ml of water to the 100 ml cylinder.
Then, drop in grovel uniil the some omount of water is disploced os in step 4.
Remove the woter qnd gravel.
Dry the grovel on o poper towel.
9 - Placethe grovel in tube 3.
fnsert the stopper fitted with o colibroted pipetle.
10 - Using the test tube tongs, loy tha three respirometers in the woter
bqth, with the pipettes resiing on the mosking tope sling (seeFigureb).
Qently set the weight opparotus ocross the three tubes to submerge them.
Woit 7 minutes so the temperature of the tubes ond the woten is the some.
11 - Remove the sling.
Using the test tube tongs, position the three respirometers ond the weight
dpporotus dtagonallyin the tub so thot they loy entirely under water ond so
the pipette colibrotions con be eosily read (keep those warm fingers out of
the woterl).
Water will enter the pipettes fon o short distonce ond then stop.
ff woten continues to move into o pipette, check for leoks in the
respiiomefer (with fingernoil, try gently pushing down the waxy parafiln
thot seols the pipette to the stopper hole. If this doesn't correct the
problem, exchange your pipette stopper for onother from the cort.)
pipetl
tip

Nome Beon lob p. 3
t? - Allow the respinometers to eguilibrote for 3 minutes.
To the nearest 0.01 ml, record in the toble the initiol position of woter in
eoch pipette.
Woit 10 minutes ond record in the toble ony chonge in woter position.
Woit 10 more minutes, ond ogain record ony chonge in woter position.
13 - Record in the toble the net change fon eoch test tube - thot is, the
initial reoding for eoch tube minusthat fube's ZO-minute reoding.
Did the water position chonge in tube 3 (grovel only)?
By how much? _ ml.
Add this number to the net chonge you obsenved in tubes l ond 2 if the
woter position moved toword the tip of the pipette.
Subtract this number from the net chonge you observed in tubes 1 ond 2 if
the woter position moved toword the tube. This is o correction for ony
chonge in volume due to otmospheric pressure chonges or temperoture
chonges.
Complete the foble.
Aerobic Cellular Resp rotion toble
Test
tube Contenis
1
3
Initio I
reodrn9
Reoding @
10 rninuies
Reading @
20 minutes
t4 - At the end of the experiment:
Place the used gravel ond beons in the dishes provided on the side counter.
Use the hooked probe to remove the cotton bolls-
Wosh the test tubes ond set them in the dish droiner.
Return oll other eguipment to the cort.
Net
cnonge Correction
CoffecIed
net change

Cellular Respiration Lab Write Up
Include the following in a Word document: Be sure to label each distinct section of the write up
1. Title
2. Background Information - Write a paragraph that answers and summarizes the following:
a. What is the purpose of cellular respiration?
b. Explain the entire process of converting glucose to ATP through aerobic respifation. Include a discussion of
each step in the process, where it occurs and what it produces.
c. Explain how the rate of cellular respiration was measured in the lab. Relate this measure to process of cellular
respiration and explain why that is an effective way to measure the rate of cellular respiration.
d. Explain why KOH was required in the lab. Relate this need for KOH to the process of cellular respiration.
3. Hypothesis - Write the specific prediction that you tested as an if...then statement.
4. Experiment
a. Summarize the procedures that you followed in this experiment
b. ldentify the independent variable
c. ldentify the dependent variable
d. Explain how the dependent variable was measured
5. Data - Make a data table. Include both class and group data if appropriate
6. Results
a. Graph your data - remember the independent variable is placed on the X axis, the dependent variable is on
the Y axis
b. Label what is graphed on each axis
7. Conclusion
a. Restate your hypothesis
b.Using data from the exp€riment, explain whether you accept or reject your hypothesis
c. ldentifi/ any possible sources of error that might have impacted your data_
d. Discuss what you learned about cellular respiration

Name per._ Date
Cellular Respiration Lab Write Up Grading Rubric
l4s
Write your name on this sheet and turn it in with your type written lab report
1. Typed: 0 not typed 2 typed
2. Title: 0 not oresent 2 oresent
3. Sections Labeled: 0 no sections labeled I some sections labeled 2 all sections labeled
4. Backgroundlnformation
Paragraph form: 0 not in paragraph form 1 partially in paragraph form Z paragraph form
a. Cellular respiration purpose:0 not present 1 present incomplete/incorrect 2 present, correct
b. Process of Cellular Respiration:
Glycolysis: 0 not present 1 present incomplete/incorrect 2 present, correct
Krebs Cycle: 0 not present 1 present incomplete/incorrect 2 present, correct
Electron Transport System: 0 not present 1 present incomplete/incorrect 2 present, correct
c. Measurement of Oxygen: 0 not present 1 present incomplete/incorrect 2 present, correct
d. Role of KOH: 0 not present 1 present incomplete/incorrect 2 present
5. Hypothesis: 0 not present 1 present,illogical 2 present, logical, wrong format 3 present, correct
6. Experiment
a. Procedure summary: 0 not present 1 present incomplete/incorrect 2 present, correct
b. Independent variable: 0 not present l present incorrect 2 present, correct
c. Dependent variable: 0 not present l present incorrect 2 present, correct
d. Dependent variable measured: 0 not present 1 present incomplete/incorrect 2 present, correct
7. Data: 0 not present 1 present incomplete/incorrect 2 present, correct
8. Results
a. Graph: 0 not present 1 present incomplete 2 present, variables on wrong axes 3 present, correct
b. Axes Labeled: 0 not present 1 present incomplete/incorrect 2 present, correct
9. Conclusions
a. Hypothesis restated: 0 not present 1 present incomplete/incorrect 2 present, correct
b. Conclusion: 0 not present 1 present illogical 2 present, no data 3 present correct
c. Sources of Error: 0 not present 1 present incomplete/incorrect 2 present, correct
d. Discussion of Cellular Respiration: 0 not present 1 present incomplete/incorrect 2 present, correct