Cellular Respiration Lab Report

5/12/2018 Cellular Respiration Lab Report - slidepdf.com

http://slidepdf.com/reader/full/cellular-respiration-lab-report 1/6

Cell Respiration Lab Report

Abstract

The introduction is where you introduce the concept of how to do

the cellular respiration lab. The method is where you show the steps of

how to do the lab correctly. The results is how you show the reader of the data that you received, and to compare that with anyone else whowants to do the same lab. The discussion is where you discuss with the

reader how your results went, and if any problems occurred, how and

why they occurred the way that they did. The conclusion is where youconclude the lab, and allow any other specific types of evidence tofurther help with the conclusion of the lab.

Hypothesis

At a warmer temperature, more oxygen will be absorbed by the peasthan at a cooler temperature, and germinating peas will absorb more

oxygen then nongerminating peas both room temperature and 10

degree Celsius conditions.

Introduction

In this lab we will measure oxygen consumption during

respiration as the change in gas volume in respirometers containinggerminating or nongerminating peas. Respiration refers to two

different but related processes. Respiration is the active acquisition of

O2 by an organism and cellular respiration is the release of energyfrom organic compounds by metabolic chemical oxidation within eachcell. Note the equation below for the complete oxidation of glucose.Oxygen is required for this energy releasing process to occur.

C6 H12 O6 + 6 O2 -> 6 CO2 + 6 H20 + 686 kilocalories of

energy/mole of glucose oxidized.

The chemical oxidation of glucose has important implications in

relation to the measurement of respiration. You will measure the:

1. Consumption of O2 during the oxidation of glucose

2. Production of CO2 during aerobic respiration

3. Consumption of O2 and the release of CO2 during cellular

respiration

In this experiment, the relative volume of O2 consumed by

germinating and nongerminating peas at two different temperatures



will be measured. Also the CO2 produced during cellular respiration

will be removed in the presence of potassium hydroxide and will form

solid potassium carbonate by the following reaction: CO2 + 2 KOH ->K2CO3 + H2O. Therefore the change in the volume of gas in the

respirometer will be directly related to the amount of oxygen

consumed. In the experimental apparatus, if water temperature andvolume remain constant, the water will move toward the region of lower pressure due to the consumption of O2. The vial with glass

beads only will permit detection of any changes in volume due to

atmospheric pressure changes or temperature changes. The amount of O2 consumed will be measured over a time course. The experimentrequired six respirometers to be set up as follows.

Method

First, both a room temperature bath and a 10 degree C bath

should be set up immediately to allow for time to adjust thetemperature of each. Add ice to attain the 10 degree C bath. Whichthe baths are equilibrating, obtain a 100-mL graduated cylinder and fillit with 50 mL of H2O. Drop in 25 germinating peas and determine the

amount of water that was displaced. Record the volume of 25

germinating peas. Remove these peas and place them on a paper

towel. They will be used in respirometer 1.

Second, refill the graduated cylinder with 50 mL of H2O. Drop 25

dried peas into the graduated cylinder and then add enough glass

beads to attain a volume equivalent to that of the expandedgerminating peas. Remove these peas and beads and place them on a

paper towel. They will be used in respirometer 2.

Third, refill the graduated cylinder with 50 mL of H2O.Determine how many glass beads alone would be required to attain a

column equivalent to that of the expanded germinating peas. Remove



these beads and place them on a paper towel. They will be used in

respirometer 3.

Fourth, repeat the procedures above to prepare a second set of

germinating peas, dry peas + beads, and beads for use in

respirometers 4, 5, and 6, respectively.

Fifth, to assemble 6 respirometers, obtain 6 vials, each with an

attached stopper and pipette. Place a small wad of absorbent cotton in

the bottom of each vial and, using a dropper, saturate the cotton with15% KOH. Make sure that the respirometer vials are dry on the inside.DO NOT get KOH on the sides of the respirometer. Place a small wadof dry cotton on top of the KOH-soaked absorbent cotton. It is

important that the amounts of cotton and KOH be the same for each

respirometer.

Sixth, place the first set of germinating peas, dry peas + beads,

and beads in vials 1, 2, and 3, respectively. Place the second set of

germinating peas, dry peas + beads, and beads in vials 4, 5, and 6,

respectively. Insert the stopper fitted with the calibrated pipette. Placea weighted collar on each end of the vial.

Seventh, make a sling of masking tape attached to each side of

each of the water baths to hold the pipettes out of the water during anequilibration period of 7 min. Vials 1, 2, and 3 should rest in the room-

temperature water bath and vials 4, 5, and 6 should rest in the 10

degree C water bath.

Eighth, after the equilibration period of 7 min, immerse all sixrespirometers entirely in their water baths. Water will enter the

pipettes for a short distance and then stop. If the water continues to

move into the pipette, check for leaks in the respirometer. Work

swiftly and arrange the pipettes so that they can be read through thewater at the beginning of the experiment. They should not be shifted

during the experiment. Hands should be kept out of the water bath

after the experiment has started. Make sure that a constant

temperature is maintained.

Ninth, allow the respirometers to equilibrate for 3 more min and

then record, to the nearest 0.01 mL, the initial position of water in

each pipette. Check the temperature in both baths and record in Table5.1. Every 5 min for 20 min, take readings of the water¶s position in

each pipette. Record the data in Table 5.1.



Results

The main result of this lab was that all data points towards thefact that germinating peas absorb more oxygen when kept at roomtemperature than at 10 degrees Celsius.

Table 1 Data:

Temp.

(C)

Time

(Min)

Beads AloneGerminating

PeasDry Peas and Beads

Readingat Time

x

Diff.*Reading

at Time xDiff.*

Readingat Time

X

Diff.*

10

Initial 0

9.3 7 9

0-5 9.3 5.6 1.4 8.2 .8

0-10 9.3 5 .6 7.5 .7

0-15 9.3 3.6 1.4 7.3 .2

0-20 9.3 3 .6 7.3 0

25

Initial 0

9.3 8.7 9.5

0-5 9.3 7.5 1.2 9.5

0-10 9.3 6 1.5 9.50-15 9.3 4.8 1.2 9.5

0-20 9.3 3.9 .9 9.5

Although confusing, these results show that germinating peas absorb

more oxygen than the dry peas at both temperatures. This also shows

how the germinated peas absorbed more oxygen at room temperature

than at 10 degrees Celsius. Also, the dead glass beads stayed at a

constant rate of zero during the experiment.

Figure 2:



(10C Beads and 25C Beads are in the same location all the way through)

Discussion

Our results, seen in Figures 1 and 2, fully uphold our hypothesis

(At a warmer temperature, more oxygen will be absorbed with thegerminating peas than would be in cooler conditions).

The data that best upholds our hypothesis is found in Figure 1, whereyou can see that the amount of oxygen absorbed is higher with the

warmer temperature than the amount absorbed in the cooler

temperature.

Conclusion

After reviewing the results of this lab, I have learned that at a

warmer temperature more oxygen will be absorbed with thegerminating peas than would be at a cooler temperature, and that

germinating peas absorb more oxygen than dry peas in both

conditions.

References:

0

1

2

3

4

5

6

7

8

9

10

Initial 5 Minutes 10 Minutes 15 Minutes 20 Minutes

10C Beads

10C Germ.

10C Non-Germ.

25C Beads

25C Germ.

25C Non-Germ.



Cellular Respiration Lab Manual

Documents

Cellular Respiration Lab Report